It is a matter of opinions,... most movement in animation and in real life starts from zero, then reaches a certain speed, then decelerates and stops gradually, constant linear motion can feel robotic.

In the user preferences you can set the default interpolation for New F-curves
to one that suits your needs:


How can I easily model an extruded organic shape?

You can easily do it with a curve. Press Shift+A > Curve > Circle.

In Edit Mode do something like this:

Then:

Hope that helped you!


AttributeError: 'Mesh' object has no attribute 'view_frame'

Camera object

the argument obj must be a camera

>>> bpy_extras.object_utils.world_to_camera_view(
world_to_camera_view(scene, obj, coord)
Returns the camera space coords for a 3d point.
(also known as: normalized device coordinates - NDC).
Where (0, 0) is the bottom left and (1, 1)
is the top right of the camera frame.
values outside 0-1 are also supported.
A negative 'z' value means the point is behind the camera.
Takes shift-x/y, lens angle and sensor size into account
as well as perspective/ortho projections.
:arg scene: Scene to use for frame size.
:type scene: :class:`bpy.types.Scene`
:arg obj: Camera object.
:type obj: :class:`bpy.types.Object`
:arg coord: World space location.
:type coord: :class:`mathutils.Vector`
:return: a vector where X and Y map to the view plane and
   Z is the depth on the view axis.
:rtype: :class:`mathutils.Vector`

Running your question script with a mesh object as context will produce the error shown.  Make sure obj.type == 'CAMERA'.


Changing camera background image proxy for easier viewing

Are you using Blender 2.83?
I would say you are luckier than me because when I change the proxy resolution I don't have any change at all in the 3D viewport :/
I am not sure if a manual reload of the clip is required - or a full project file reload maybe?
In any cases a pink image means the expected media is not found at the current time. This can be due to:

The current time your scene is using is out of the media range (it can be after of before, even if there is a strange behavior for before in the way that after some time jog the first frame of the media is displayed instead of the pink fill). By moving the current time you should be able to reach the media range (which should not have changed btw).
Or the proxy has not been generated, for some reason...

This is not really an answer but...
At this point I am wondering if this property is working correctly on this version...


It's not perfect to see in the screenshot, but isn't the object just circled around the world's origin (where the 3D cursor is at the moment)? So did you try going to Object Mode, right-clicking the object, then in the context menu choose Set Origin > Origin to 3D Cursor?
EDIT: Or maybe it's not circling around the world origin. What about selecting the vertices that are furthest on X and -X as well as the ones furthest on Y and -Y. When they are selected, Shift+S > Cursor to Selected, go to Object Mode and like suggested before, set origin to 3D Cursor?


select the same vertices on view port and UV editor without selection sync? - python

BMLoop.vert

When iterating through the face loops (, which in case below is f.loops), the vertex of each loop element (l), is the vert property BMLoop.vert   of the loop. (l.vert).

    for l in f.loops:
        luv = l[uv_layer]
        if l.vert.select:
            print(luv.uv)


I don't understand how to UV map my model while keep all parts separated

The seams you have created aren't enough. You need to add additional seams to make it unwrap properly, especially on the hand, the lower body (some edges aren't set to seams). Also, there's some unmerged verts in-between the breasts.


I don't exactly know what you're going to say, just type "300" on the third text field (in the photo, the one with "1")


Material Colors don't show when exporting?

Most exporters will only handle very basic Principled BSDF materials. You can make a Principled material that will look like you want by putting black in the "Base Color" socket and putting the color you want in the "Emission" socket. (You may also want to try cranking the roughness up to 1.)

I tried exporting this with .fbx/.obj/.glb and reimporting, and they all worked.


Background images not showing up at all in persp or ortho view

Background images will only be displayed in:

Camera Prespective view (Numpad 0)
Any of the preset Orthographic views:

Front/Back (Numpad 1 or Ctrl Numpad 1)

Right /Left (Numpad 3 or Ctrl Numpad 3)

Top/Bottom (Numpad 7 or Ctrl Numpad 7)

To toggle between Prespective and orthogonal view use Numpad 5


why are the hair particles showing up on the origin point?

Just had the same problem. I've joined 2 objects (one with a modifier) and separated the meshes again into two objects. This copied a Bevel modifier on the object. The modifier caused the particle origin problem.
Either remove the modifier or tick the checkbox Use Modifier Stack in Emission → Source → Emit from.
This solved the issue and the particles are emitted from faces again.


Many import/export options include a scale to use when importing/exporting.

When exporting to fbx from blender set the scale to 0.01

When importing into blender go the opposite way, set it to 100.0

Another option is to change the units scale in blender to change the sizes shown in blender. If you set this and save the startup scene, it will be set that way each time you start blender.


In pose mode, select the bones you wish to reset.  Use a "hide selected" operation (shift h for me) to hide all other bones.

Open a graph editor view.  Make sure "only show selected" is enabled, in the upper right corner of the graph editor.  Click on the "filters" button and enter "location" (no quotes) in the "f-curve name filter" field, which has a magnifying glass icon in it.

Now you only have location keyframes of your selected bones.  In graph editor, select all and delete.

In 3D window, use a "clear pose location" operation (alt g for me.)

Optionally, keyframe at the beginning and end of your animation.


Easier way to orient custom bone shapes?

I found it very useful to work with "free rotate". You select a bone in pose mode and you press  R, R. First R for rotate, second R for free rotate. You get a very natural way of rotating that way.


How to apply Corrective Smooth as Shapekey?

This is a quirk of how the Apply as Shapekey works. The mechanism is outside the specific modifier's logic.

Essentially when you click Apply as Shapekey blender takes the unmodified mesh and adds just the modifier that your are applying to the mesh, then uses the resulting shape. For corrective smooth, this means nothing happens, as corrective smooth needs other deformation in order to do anything.

There is however a workaround for this. Blender comes bundled with and addon called Corrective Shape Key which can generate a shape from the whole combined mesh as a corrective shape. To do this you need to first use the addon to create a duplicate for editing, and then disable the corrective smooth, and then add the dupe back as new shape using the addon's functionality to reverse transforms.


Multi Cams at the same time in the same Scene

In Blender 2.8 you can now select a "Local Camera" to look through per window. Use the 3D view properties panel N-Key. Select a camera that isn't the Scene camera and turn on "Use Local Camera".

This can be useful if you are rendering 2 concurrent views of the same animation.


How to snap object back to its original position

Resetting all Transform values to 0 is Alt+G for location, Alt+R for rotation and resetting scale to 1 is Alt+S. After performing these three steps Transform location will be (0, 0, 0), rotation (0, 0, 0) and scale (1, 1, 1).
To set it back to a different location/rotation/scale, these differing values should be set in the Delta Transform properties of the object. Delta or Δ stands for (among other things) "difference" in mathematics and means in this case the divergence from the "normal" Transform properties.
Looking at this cube, it has a Transform location and a Delta Transform location. They have to be added together to get the actual world location of the cube (or multiplied for scale):

In case your object has Delta Transforms, then resetting the Transform values will result in (0, 0, 0) + Δ(x, y, z). So this way your object resets to a location different from the world origin.
Now, moving an object by hitting G only changes the Transform location, not the Delta Transform. If you moved an object to a location which should be its new "original" location, then you can apply these transforms with Ctrl+A > Apply > All Transforms to Deltas. In the options you can then also choose if you want to apply all transforms or just Location, Rotation or Scale and if you want to reset the normal transforms.
After doing it you can see that now the Transform location of the cube is reset to (0, 0, 0) while the new Delta Transform location is (7, 2, 1). This is its new "original" location. When you move the cube with G, resetting the transform with Alt+G moves it back to (7, 2, 1).


Boolean modifier doesnt render correctly

edited to answer the question better
go into latest version of blender (2.91) and try using the new booleans they added (Fast, Exact) i havent used these very much so it might not work, and also make sure that the meshes arent the same height or there will be weird artefacts so try making the subtracting mesh and make taller, this is because the boolean system has problems working with meshes that are exactly the same, (like duplicating an object and leaving it at the same place, blender cannot handle the two meshes and breaks)
for the shading artifacts i recomend recalculating the outside normals go into edit mode, select all faces or vertices, then select mesh, normals, recalculate outside, hope this edit helps


Compositor - How to math same Result for any Render Size

The current compositor is not relatively aware. Hence some pixel based nodes give different on different resolutions. There is a new design for the compositor that will overcome this issue, but this still needs a lot of development time. https://developer.blender.org/T53790


Should Every Different Textured Piece Be It's Own Object

If you're just concerned about how the object looks, there might not be any reason to make them separate objects; multiple materials can be assigned to a single object:

Add a material slot and new material
Select some vertices
Assign the material to the selected vertices


I know you've already tried proportional editing, but I think you ought to be able to get what you're looking for using it.

Try selecting the bottom edges and scaling it down with proportional editing and linear falloff. You'll then need to use the mouse wheel to adjust the proportional editing size.

If any vertices are slightly off, you can grab them and snap them to the edges of the bottom mesh.


Animation positions and animate along the path - Animation nodes

For the first question:

It seems you need the Object ID Key feature to store the initial transformation info for the objects. Here is how to use the Object ID Key node:

IMHO, the whole nodetree could be optimized like this:

For the second question:

A basic example setup would be:

BTW, there is a nice template called Distribute Instances on Spline, which is a great start to learn how to make things working like this. You can find it in Templates menu on Node Editor's header.


To capture a single key, the event param of prop in UILayout needs to be set to True and the corresponding property needs to be an EnumProperty with ALL the key codes mapped.

When the user presses a key on the control, the EnumProperty item that is related to the code of the key pressed, gets selected.

Please post your answer if you have any better alternative.


Subdividing arbitrary face into smaller faces

You can use Grid Fill to fill faceless circle.

Select all vertices, press CTRL+F > Grid Fill, adjust Offset as you want, also you can check Span value.

  Note: This will only work with even number of vertices.


You could try the Decimate Modifier

This shows the reduced mesh from 27K to 2.7K faces:

You could also switch to smooth shading with an edge split modifier to flatten the triangles on the outer ring.


OK, I'm still not sure what you need exactly, how it differs from what you already got or why yours is not satisfactory, but here is what I came up with.

Just add a simple cube to your scene, and a small Metaball. Adjust the Meta Ball size as desired, but make sure you apply the scale and adjust precision correspondingly afterwards.

Now add a particle system set to Volume to the Cube object, and under Render as particle object add to it the Metaball. Adjust the number of particles as necessary. A high number is expected, and so is the corresponding slowness and unresponsiveness, just give it a little.

Make the particle system emitter invisible (make the cube draw as Wire only so you can see what you are doing too), and tick Unborn and Died, also turn off physics.

Once happy with the settings select the original metaball (not the cube or particle system) and convert it to a mesh. Manually erase the stray original metaball, then you can add a Boolean modifier to it, and intersect with the original cube mesh.

To keep distinct materials at the intersection faces just add a second material slot to the object with the Boolean modifier before applying it.


As part of the same mesh, it would be very dificult, but you can separate the leafts into individual objects, that way you can put the same texture to all of them.

In order to do so, you must select all the leafts whit A and then Press P and choose by Loose Parts. then you can asing the same material to all the individual leafts.

It should be posible to use unwrap and uv textures to return them to the same object, but i'm  not so sure, so lets keep it that way, good luck.


Cycles Material "Texture missing" in render?

Update!

Apparently it has something to do with an out of memory error (since this is just a background for  gigantic scene with hundreds of textures)

As you can see it doesn't render properly when all objects are visible

But as soon as I hide every object except for example a tree that isn't rendering properly, everything works as it's supposed to

Blender gives no CUDA errors though.. I'm really confused.
I have 10GB or RAM installed and a GTX 550 ti with 1GB btw if that helps

SOLVED

Apparently there was indeed a CUDA out of memory error. It's fixed by just switching to CPU render.

Thanks everyone for their input!!!


Why does my loop subdivide not extend around the whole shape?

You probably have duplicated vertices. Here I ripped a few vertices (and moved them away which isn't the case in your model) to interrupt the flow of the loop cut:

This can be easily fixed by Remove Doubles.


Texture shows in render preview but not in Render

I am reasonably sure, that the wooden "table" is set to not visible in the final render. In the Object outliner scroll down and  check if the camera symbol for "restrict rendering" (rightmost symbol in the outliner) is checked/unchecked on the object with the wooden texture.

check in the wiki page under "Toggling object-level restrictions"

https://en.blender.org/index.php/Doc:2.6/Manual/Data_System/The_Outliner

Also check

Why does my object not show up?

Render result is completely blank?


One Render layer with a transparent background and one with sky?

Keep the Sky option on.

Then make two render layers. One with The sky option enabled.

And one without it:

The one with the sky disabled will have a transparent background.


Blender Internal Render.  Material Texture Panel.

Size XY 8, 8.

Size XY 2, 2.

Size XY 1, 1. Mapping Extension Repeat. Default.

Adjust offset values to suit you.

The plane has a simple UV Unwrap.  UV Coordinates not further modified.


Extracting coordinates (x y z) from a BVH file

You can find a lot of helpful information by taking a look at Blender's import and export scripts for BVH located in /your/install/dir/2.80/scripts/addons/io_anim_bvh or if you have cloned the repository /your/git/repo/blender-git/blender/release/scripts/addons/io_anim_bvh or online in diffusion.

As you can see in the importer (line 173), the file contains so called channels which contain the x,y,z-coordinates. Since I'm not familiar with the format I can't tell you exactly how the matrix transformations work, but given that the importer script is rather short you may be able to figure this out on your own.


How to fix blank space on the bottom of lighting HDRs

What you are seeing is blank space not stored in the HDR. Since the lighting received from the ground in real life is actually quite minimal, this information is not included in order to save memory. Usually you will have an environment providing those reflections in your scene instead.

To get around this issue, you can do a few things:

Change the camera angle
Rotate everything away from the horizon
Add some horizon elements
Use a different HDR

Camera Angle:

Move the camera so that the black is no longer visible

Rotate Objects:

Just rotate the whole scene so it is angling towards the camera

Horizon Elements:

These could be mountains, trees, hills, etc.

Now you mention that you do not like the camera angle when moved very low, and I understand that. Really your only option is to (if you have the purchased version) add a different HDR, or add some horizon elements like trees, mountains, etc. A scene that consists of just a house on a hill can be somewhat amateurish, as beginners do not like to add nature to their architecture renders.

Do a little more research, and you will find that almost all the powerful Arch Viz images are closer, and have convincing surrounding elements. I think that maybe this issue will help push you to explore more creative angles and environment choices. Such will only result in a more powerful result.

If you still want to use your original idea, I would recommend making whatever would be on the other side of the valley, or over the hill. Having some atmospheric fading distance wise will really help sell the effect, making it more believable that it is on a hilltop.


My soldiers all march to the same spot, how do i give them seperate orders simulanelously?

To make every characters go to a certain target whenever you click the ground we create flag object and set it as a target for the selected characters,
when all the characters reaches the flag, it gets deleted

Details :

we have the function main() which is excuted when you MMBclick on the ground this function :

creates a new Flag object at cursor position
loop through all objects and find the selected ones that have Move property,
for each found object :
change the Steering actuator target to this new Flag
increment the Flag Followers property by one
set the object properties Active and Move to True
when Active and Move are set the object start seeking the flag

this is done with this part of code :

main():
.......
    flag = scene.addObject("Flag", "Tracker", 0)
            for obj in scene.objects :
                if obj.get('Select', False) and 'Move' in obj.getPropertyNames() :
                    obj.actuators["SeekTracker"].target = flag
                    obj['Move'] = True
                    obj['Active'] = True
                    flag['Followers'] +=1

The Flag has property Followers which indicate how many objects have it as a target, so if it has no followers it should be removed , for this we have a function flag_self_check() which does that, the code part for this is :

def flag_self_check():

        cont = logic.getCurrentController()
        own = cont.owner

        if own['Followers'] == 0 :
            own.endObject()

but what makes the Followers count goes down ? it is the object, the moving object has a near sensor to detect the flag when the object gets near the flag it stops Moving and decrement the flag Followers count by one

def reach_dest():

        cont = logic.getCurrentController()
        own = cont.owner
        sen = cont.sensors["Near"]

        if sen.positive :
            hit_flag = sen.hitObjectList[0]
            if hit_flag :
                if hit_flag == target :
                    hit_flag['Followers'] -= 1
                    own['Move'] = False

i have added if hit_flag == target : so moving object don't stop at the wrong flag when passing by


The reason that does not work is because of how the keyboard sensor works, it essentially is stopping and restarting the sound.

What you need to do is have a game property (A boolean set to true). The keyboard sensor is plugged into a Property actuator set to Toggle.

It is then that property that controls the sound actuator. Add a Property sensor, set its Value to "True", the Property to the game property created earlier, and leave the Evaluation type set to Equal.

In the end this is how the logic bricks should look.


Correct code for: set Snap to Pixel = True/False as Pie menu in UVEditor

You can use wm.context_set_boolean or wm.context_toggle to achieve this.

The code should look like this:

op_props = pie.operator("wm.context_set_boolean", text="Snap to pixels")
op_props.data_path = "space_data.uv_editor.use_snap_to_pixels"
op_props.value = True

#or

pie.operator("wm.context_toggle", text="Snap to Pixels").data_path = (
    "space_data.uv_editor.use_snap_to_pixels")


How can I create a "pin and catch" for my 3d print so it will fit in my printer and connect

Answering the second question first, yes, you could keep all of the component parts in a single file. But depending upon the printer driver software you intend to use to print your creation, you may have to export the various parts out individually to separate files for printing purposes.

Looking at your blend file, and your question, your proposed 3D object will not print very well on the 3D printing systems I am familiar with, if subdivided according to the illustration in your question.

The first challenge I see is your stated proposal to use a "square pin ... and square hole". Depending upon how you intend to orient the pins and holes, I see this as a potential challenge because 3D printers do not print horizontal "square holes" well. You'll need a different method--or methods-- of joinery.

The second challenge I see in the ~.blend file I downloaded is the slot in the ring opposite the two "ears". The slot is a "hole", which again, cannot be produced on a 3D printer.

The third challenge is in the shape of the ears. The 3D printers with which I have slight familiarity require a flat surface on which to form the object to be printed; they can't print an overhang.

In the absence of information on the intended size, this image
(source: core.com)   shows how I would divide the item for 3D printing. First, I'd divide the item in two along the vertical plane shown by the blue line in both sides; then I'd further divide the item along the plane shown by the yellow line, creating four sections: two of the half with the ears, and two with the half with the slot. I'd place the two sections with the ears so that the part of each section co-incident with the yellow horizontal plane is on the printer bed. With the half with the slot, I'd place the two sections with parts of the slot on the printer bed so that the outside of the piece is along the printer bed.


Weird deformation with fingers (automatic weights)

The rigging is bad: Select the armature, shift select the object, switch to Weight Paint mode, then select each bone, you’ll see what part of the mesh they affect. You can see that the first thumb phalanx affects the palm, which is not supposed to do. Some other phalanx also affect the palm.

So you need to:

Create a bone for the palm itself
Parent this bone to the last arm bone (Keep Offset mode).
Parent each first phalanx to this bone (Keep Offset mode).

In Weight Paint mode, paint the influence of the palm bone (enable the 2D Falloff option to paint through the mesh).

Also remove all the unnecessary influences.

Now it works fine (don't know why your arm has 3 bones though).


That panel was shuffled around a bit since the tutorial was made. The option you want is now called Maximum draw type:

Also make sure Optimal display is enabled on the subsurf modifier.


Bug? Voxel Data Animation Issue (Still Frame Number Keyframe not rendering)

Sorry about this, I figured it out.

It was my own mistake

I checked the option Still Frame Only.
To anyone reading this, MAKE SURE IT'S UNCHECKED

Edit: I could not find any information about this online so I made a tutorial.
https://hackmd.io/s/rketOixDG


Wrong 3D Cursor - Far away from the scene

Press Shift+C to re center the 3D cursor in your scene, if this solves your problem you will want to re-save your startup file (File> Save Startup File) so you don't have to re-center the cursor every time you restart Blender.


Shrinkwrap Modifier - Can't select Vertex Group

You are supposed to create a vertex group on the object which hosts the modifier, not the target object. You currently can't set a target vertex group with the shrinkwrap modifier.

The vertices will be projected against all of the target object's geometry.


How do I save a blend in the 2.79 format in 2.8?

This will seem crazy, but, select all of your object and CTRL+C on 2.80, open 2.79 and PASTE (ctrl+V) right on the viewport. I know right? I saw it on a blendCon


Check if bone is manipulated by constraints

All constraints on the active pose bone,

import bpy
context = bpy.context
pbone = context.active_pose_bone

for con in pbone.constraints:
    print("Constraint:", con.type)
    target = getattr(con, "target", None)
    if target:
        print("Target:", target.name, con.subtarget)
    print()

Other ways to access pose bones of an armature object

# armature object has the pose.bones collection
arm_obj = bpy.data.objects.get("Armature")
if arm_obj:
    #bone named "Bone"
    pbone = arm_obj.pose.bones.get("Bone")
    #items() gives key value pairs
    for name, pbone in arm_obj.pose.bones.items():
        print(name, pbone)


Using Python to Copy Rotation of Pose Bones

See this section of the api documentation. Setting PoseBone.matrix probably does the calculations required for PoseBone.matrix_basis but does not update the value of the underlying DNA world matrix property, which is wierd. Here is a script which uses the scene.update method:

import bpy

class BoneMatrixCopier:
    def __init__(self, obj, scene):
        self.obj = obj
        self.scene = scene
        self.pose_bones = obj.pose.bones

    def update(self):
        self.obj.update_tag({'OBJECT'})
        self.scene.update()

    def get_ik_bone_name(self, name):
        return name.replace("Bone", "BoneIK")

    def copy_matrix(self, bone):
        self.update()
        bone.matrix = self.pose_bones[
            self.get_ik_bone_name(bone.name)
            ].matrix

    def copy_matrices(self, root_bone_name):
        root_bone = self.pose_bones[root_bone_name]

        self.copy_matrix(root_bone)
        for bone in root_bone.children_recursive:
            self.copy_matrix(bone)

bmc = BoneMatrixCopier(bpy.data.objects['Armature'], bpy.context.scene)
bmc.copy_matrices('Bone')


How do I make a render with a background image in Blender Render?

The are plenty of ways to do this.

Place a texture on a plane in the 3D View. UV Mapped plane.
Render with a transparent alpha for the cube.  Place on background image by whatever image processing means including GIMP or the Blender Compositor.
There are also HDRI images free for the background


How can I prevent my posed rigs from defaulting back to the static stance? Also undo questions

Just press I to insert a keyframe or turn on auto keyframes, so that everytime you modify anything that can be keyframed, a keyframe is saved.

Auto keyframe is the red record button on the bottom right of the picture


Where to place lowpoly object compared to highpoly object?

Normaly, the lowpoly is in the exact same place as the highpoly object. But if the lowpoly is completely flat, it could be "above" the highpoly. Look at this answer where I project the normals upwards with baking.

Creating game models for android

If your lowpoly object is not flat, you can't move it if you want to bake normals.

If you are willing to bake the lowpoly piece by piece, and each piece is relatively flat you can move details from the highpoly object. Then you must fiddle with the offset parameter and this is usually a pain to get right.


On the first color ramp (with the blue in it), change the alpha for the non-blue stops to zero. Then, pipe the output color into Emission Color, and the output alpha into Emission Strength.
Edit: Like this.


How do I increase the 'View Orbit' amount?

The setting of the short cuts can be found in the user preferences, input tab.

Their names are 'view orbit'. The tricky thing is that the values needs to be in radians.

But you can use Python (transparently) to define the value you want in degrees. So to have 22.5 degrees, type "pi/8".

Now you can orbit with the wanted rotation :

Edit : you can also type "radians(22.5)". It seems all the math functions (math Python module, probably) are available.


Is it possible to make half of an object semi transparent and the other half non-transparent?

Yes, this can be done by assigning different materials to the same object as shown below.

I added a cube to the scene at origin and scaled it to be bigger
Then I added a sphere to the origin which is now located inside the cube
I added a material to the cube as shown below:

I then checked and turned on the transparency and decreased the the Alpha value as shown below:

Then I added a new material and set its color to red as shown below:

Then I switched to edit mode, switched to face mode and selected couple of faces and clicked assigned to the red material as shown below:

Then render and as shown below the grey material is transparent showing the sphere inside while the red material is not:


It's a positive symmetrical triangle-wave, amplitude Scale, period  2 * Scale, 0 at 0.

Here's the function illustrated with 'Scale' (from the bottom up) set to 1, 0.5, and 0.333.
These planes are 8 units across, and 2 up, 0 at center.
You could roll your own like this:
PingPong(Value) = Scale - abs( (abs(Value) % (2*Scale)) - Scale)

..but someone else might come up with a neater way.. :)
You could wrap up the node like this to give more intuitive inputs?


You can create something like the following. You can also adjust the IOR to your liking; this is just a sample at 1.2.

Result with Shady Puck in the background:

Mesh sideview profile:

Modeling

Start by keying Shift + A and going to Mesh > Sphere. Key R, then X, then 90. Key Numpad 3 and Numpad 5 to enter Right Orthographic view. Key Tab and Z to enter Edit Mode and Wireframe View, respectively. Key B for Box Select and drag while holding down your LMB to select the following vertices.

Key S, then Y, then .3 to scale the selected vertices down to a more lens-like shape. Key G, then Y, then .48 to slide them over. You now have half a double convex lens. You should see something like the following.

Key A once or twice to deselect all vertices. Key B for Box Select and drag while holding down your LMB to select the following vertices.

Key X and choose Vertices. Tab out of Edit Mode and key Z to exit Wireframe View. Go to the Properties panel > Object modifiers tab and add a Mirror modifier. Make sure Z is checked under Axis: and nothing else. Your settings should look like the following.

Add a Subdivision surface modifier. Set the View: value to 3 and the Render: value to 4.

Key T to toggle open/close the Toolshelf. Go to Tools tab > Edit dropdown > Shading: and select Smooth.
You are now done with modeling.

Materials

This is where the magic happens. Go to the Properties panel > Materials tab and add a Glass BSDF shader. Note that you will have to be in Cycles Render for this to work. Play with the IOR: as you wont.

Materials tab:

You now have a fully completed double convex lens.

Further Reading

Many of the techniques from this piece are gathered from tutor4u's awesome Focused Text Animation tutorial.

.blend file

The following is the .blend file with the lens and Shady Puck text from the first image.


Glass should have no color.

If you give a glass shader a color,  you will get, as you pointed out in the question, "unrealistic" relfections. The reflections should indeed be untinted.

Here's an example:

What gives glass color mainly is the light that is absorbed as it goes through the surface.

A volume absorption node will give you a more realistic result, with "white reflections".

To understand when you should have colored highlights you can watch
 Andrew Price's video on the principled shader (https://youtu.be/4H5W6C_Mbck?t=646). The important concept is that dielectric Materials (including glass) will not have colored highlights. Reflections on metallic materials will be tinted with the color of the material.

https://physics.stackexchange.com/questions/213478/why-dont-dielectric-materials-have-coloured-reflections-like-conductors


How to model an object with width and depth, based only on an image that shows the outline?

I thought it would be easily fixable but your shape is a bit more complexe than I thought. If I had to do it from scratch, I would follow the shape with some extrusions, like this:

If you want to start from your current mesh, delete the extrusion to only keep the edges, don't forget to remove doubles, give some extrusions to the remaining edges, like this:

Etc... then extrude to give it thickness and give it a Subdivision Surface modifier to smooth it.

You could also convert your edges to curves, and give it thickness, but it will also need rework.


Can someone explain how to cut a circle out of this circle?

Select the object that will be the "hole" in the 2nd object,

Shift + select the target object.

Tab to enter edit mode

Numpad 7 to go to top view (the cut will be projected so the view is important).

Enter edit mode with both selected, go to mesh, knife project.

Then just remove the resulting face.


How can I make a set of vertices part of an existing plane with an imported image?

the only thing that comes to mind is subdividing the plane in edit mode. then moving your new vertices where you want them.

this may become a little more complicated if your image skews while doing this.

let me know if you need clarification. i can post some screen shots.


Calling an addon's Operator from Python - wm_operator_invoke: invalid operator call

To use the plugin in the way intended, execute() needs to be used instead of invoke(). The execute method can still use the invoke code by calling it with an event of None:

class MyAddonOperator(bpy.types.Operator):
    bl_idname = "object.myaddonoperator"
    bl_label = "My Addon"
    bl_options = {'REGISTER'}

    @classmethod
    def poll(self, context):
        return context.mode == 'OBJECT'

    def execute(self, context):
        return self.invoke(context, None)

    def invoke(self, context, event):
        do_stuff()

        return {'FINISHED'}

Now the addon can be called with bpy.ops.object.myaddonoperator('EXEC_DEFAULT')


Macro in blender? Quick way to set 1 hotkey for "Rotate 90 degrees" in UV editor?

I don't think there's a built in way to do this, so a while ago I created an add-on called UV Rotate Shortcuts.

This adds Shift+R and Ctrl+Shift+R to rotate the selected UVs by 90 degrees or -90 degrees respectively.

The rotation amount can be customised in the add-on's user preferences.


Can I Automate Converting Groups of Triangles to Quads?

Select Similar

I think there cannot be an unique answer: there are multiple possible solutions to the problem of "grouping tris into quads". For example Blender is showing one of them, that cannot be said wrong in anyway. That's its automated way to solve the problem.

You'll have to write your own algorithm in order to specify what kind of index order should be followed while packing tris. Luckly, in the provided exmple you can take advantage of another tool: Select Similar.

As long as there is a recognizable pattern in the distribution of the triangles, as in your case, you can simply select all the vertices that are ruining your quads and dissolve them.

Pick one vertex in the middle of the "future" quad, run Select Similar command with "amount of connecting edges" option, then press X and choose Dissolve vertices


How to increase this camera viewport size?

You need to activate or deactivate the N panel > View > Camera to View option if you want your camera to follow or not your zoom in and out:


Render glow over transparent background blender 3D evee

Okay, I am not good with compositing but maybe will be able to help you a bit. It is a bit cheatish way to create a false bloom using gaussian blur.
This should work with both cycles and eevee, my example is in eevee, which does not support lighting from emission material.

First a basic scene with sphere, cube and transparent background:
What we want to do is to make the cube glow. We will do it like this:

Add a new view layer, so we have two view layers.
Sphere will be excluded from one view layer, cube will be excluded from another, each of them will have their own view layer.

Lets add view layer:

Lets add collection and put cube into that collection

Set viewlayer to our first layer (defaultly named View Layer), select Collection 2 and exclude it from the layer:

Set view layer to the one we have added in step 3:

Select first collection (one with sphere, light and camera), right click it and exclude it from currently selected view layer:

What we've done so far is set two view layers, have cube in collection 2 included in View Layer.001, and Camera, Sphere and Light included in View Layer.

Now lets add emission material to our cube:

Open Compositing window, turn on Use Nodes, Auto Render and Backdrop. Two last options make preview of the render be rendered in the background whenever you change something in compositing nodes. As of this moment it seems to be requiring you to make one render before it starts working (just press f12 to render and then close rendered image).

What we are doing now is splitting image into two Render Layers, one for View Layer (with sphere) and other for View Layer.001 for Cube. Cube is blurred to create lighting aura effect and then added to cube (so we get a solid cube with blurred cube behind it). Then we add sphere from view Layer on top of that. Connecting to Composite node causes it to be renders output, Viewer node is required for Backdrop to display.

And final render:


Your normals are flipped, you can see it if you enable Face Orientation in the Viewport Overlays options, it messes up the parentage. Go in Edit mode, select all and Mesh > Normals > Recalculate Outside, or ShiftN. Then reparent With Automatic Weight.


How to give each hair particle system in one object its own color

You need to create 3 Material Slots and 3 Materials for your emitter object (1). In  this example, Blue and Red aren't assigned to any face.
For each Particle System, under Render/Material (2), select the desired material in the list.


Try to rotate an object in 'Edit Mode' (using proportional editing). Remember to match the curve origin with the object origin.

Here is the result:


Access to object location from previous frame in cycles

See the docs about drivers, they're comprehensive.
Also see TextEditor -> Templates -> Python -> Driver Functions

Add a Driver

If your object is key-framed, you can evaluate the F-Curve using a frame number like fcurve[index].evaluate(frame-1)

Add a Driver to a custom property of your object.

Make a python expression text block with something like the code below, and Run the code so the expression is added to the driver_namespace

import bpy
from mathutils import Vector

def driver_delta_to_RED(frame):
    # triggered by a frame change, any code inside here gets run.

    p = bpy.data.objects['Plane']
    current_xyz = p.location
    fcurve = p.animation_data.action.fcurves

    x = fcurve[0].evaluate(frame-1)
    y = fcurve[1].evaluate(frame-1)
    z = fcurve[2].evaluate(frame-1)

    # may want to find the top speed first, and normalize
    # this value using that information
    delta = (current_xyz - Vector((x, y, z))).length

    nodes = bpy.data.materials[0].node_tree.nodes
    nodes[1].inputs[0].default_value = (delta, 0, 0, 1.0)

    # the return value is of no relevance and can be static.
    return 0.0

bpy.app.driver_namespace['driver_delta_to_RED'] = driver_delta_to_RED

Add the function call to the Driver

if it's a frame behind or ahead of what you want, then instead of the Driver, it might make sense to add an application_handler specifically the frame_change_pre or frame_change_post handlers.

The code for Drivers and frame_change handlers is slightly different, but the app handler docs will describe how to get the current frame from inside the handler function.


How to make "object A" keep distance from "vehicle with physics" and follow path at the same time?

I suppose it kind of depends on how you're going to animate the car.  But one way would be to use a boolean.

If you think about, you're trying to find the intersection of a sphere centered on the car and the curve.  So start by making a (non-rendering) mesh for the curve, just a strip of planes with a curve modifier, then make a (non-rendering) sphere around the car:

Parent your sphere to your car, give it a solidify modifier, then give it a boolean/intersection modifier with your curve mesh and now you have an arbitrarily small piece of mesh that represents the intersection of the curve and the sphere:

Now you can create an empty (or a bone, or anything else), parent it to the car, and use a shrinkwrap constraint targeting the non-rendering sphere:

So far, so good.  But of course our sphere actually intersects our curve at two points, so let's delete half of it.  And let's subdivide our curve-modified path and make it more narrow to reduce our error.

Look, your car doesn't even have to stay on the ground.

One potential problem here is if you have a very windy curve, there may be multiple points of intersection.  You can always adjust the size of your sphere as necessary to improve handling on windy roads.


This can also be accomplished with the checker texture.


I guess after downloading the FM build you also need to download the helper addon.

http://blenderphysics.com/fracturemodifier/

This solved my problem.


How to remove all booleans (across all layers) from being displayed?

Remove the modifiers from one object. Select all the other objects you want to remove the modifiers from, making sure you select the object with no modifiers last. Press ctrl + L and select Modifiers.

All the modfiers will be cleared from every object you selected.


How to export motioned tracked mesh and background video in mp4?

For those wondering change Blender render to cycles render go to film in the render tab and check transparent. That might create a new issue I'll edit this answer when I solve.


Adjacent faces are separated on the UV map

There's a problem in your model's topology.  Do this experiment.  In the UV editor, after you've done the cylinder projection, deselect everything and then carefully select the top row of vertices:

Since you've enabled UV Sync Selection, the same row of vertices shows up in the 3D view:

But if you zoom in to the active vertex you can see an issue:

It might be easier to see in edge select mode:

the path jumps from one edge loop to the other.  I don't know how to solve this directly, but my horrible work around is this:
select one of the vertical edge loops:

delete everything else:

add a screw modifier with the same number of steps:

and apply the screw modifier, in object mode.  The result is:

Notice that I didn't mark a seam, because I didn't know where you'd want it.
I don't honestly know what the topology issue is, but this "fixes" it.


A face normal is the angle perpendicular to the face, it is used to determine reflections and lighting on the face.

A normal map is used to visually deform the surface of an object. It does this by altering the face normal for every position on the face. This fakes extra detail by altering the rendering calculation without using extra geometry.

This is where the normal input comes in, by feeding a normal map into the node you allow blender to calculate the surface colour at a given point using the modified normals and not just the one face normal.

You may find Blender Gurus recent tutorial on photorealistic wood of interest.


With default theme, these red lines are seams (cuts for UV unwrapping).

To get rid of it, in edit mode: select all and clear seam.
A
U then "clear seams"


Blender 2.8 textures not showing up in EEVEE and LookDev

WARNING: THIS IS INCORRECT.

This is normal, as these textures are not used in EEVEE. EEVEE only uses the standard "Texture" node, which references the textures in the "Texture" tab of Properties. Unfortunately, Checker Textures cannot be generated in EEVEE.

(THIS IS CORRECT)
I'm not actually sure. (I was thinking of the wrong engine.)


What's going on with my boolean difference Modifier?

From an UV sphere, this can be done with 3 magic shortcuts:

AltP to poke the faces
AltJ to make quads from tris
AltE then individual faces to extrude faces

Additionally, it can be useful to keep these new vertices in a vertex group:

because it will allow to retrieve them easily for an eventual future modification. For instance:


Blender should run okay on old hardware for some tinkering. I would only worry about buying a new computer if you experience performance issues with more complex models and rendering (especially Cycles). If you really need a lot of horse power, go for a desktop machine, laptop performance isn't ever great.

See the general specifications:
http://www.blender.org/download/requirements/

Dedicated Nvidia cards are recommended (CUDA support!), you should avoid ATI/AMD from what I've read (buggy OpenCL support etc.).


How to fix non-manifold geometry for 3D printing

In edit mode press K and use the knife tool to cut edges across geometry and make 4 sided faces.


You can delete selected vertices/edges/faces by pressing Delete or X.
To make the selection symmetrical, use either Mirror selection or a Mirror modifier

Mirror selection across X axis


I've compiled all my tracking data but when I go to default to add the object, the video isn't in the background

Solving the scene doesn't automatically set the image as background, nor does it prepare the necessary nodes in the compositor to render the scene over the video background.

Once you solve the scene press:

Set as Background.

And Setup Tracking Scene


Are there any built-in color swatches or color palette?

I don't think there is any inbuilt add-on. But you can use this free add-on. http://www.blenderskool.cf/kaleidoscope/


Check if a mesh has a material in Python

If the mesh has no materials then

1>len(obj.data.materials)

although it is also possible that it has a material slot with nothing in it

obj.data.materials[i] is None

and the complete script is

import bpy

def no_material_on(mesh):
    if 1>len(mesh.materials):
        return True

    for i in range(len(mesh.materials)):
        if mesh.materials[i] is not None:
            return False
    return True

def my_grey():
    name = "my grey"
    rval = bpy.data.materials.get(name)
    if rval is None:
        rval = bpy.data.materials.new(name)
        g=.735
        rval.diffuse_color = (g,g,g)
    return rval

def mission1(obj):
    mesh = obj.data
    if no_material_on(mesh):
        mat = my_grey()
        if 1>len(mesh.materials):
            mesh.materials.append(mat)
        else:
            mesh.materials[0] = mat

#

mission1(bpy.context.active_object)


how do I stop blender from randomly creating multiple (often disconnected) vertexs in the same place? ver 2.82a

Go to mesh > clean up > merge by distance... figured it out but any idea why it happens?


How to do seperate render passes in blender?

Actually, your question is a little bit vague, you have everything you need to begin to understand this topic on the Blender Reference Manual

Short answer, because this is a huge topic, and your question implies that the concept itself isn't quite clear for you (the reason I advised you to first read the manual ;) ), but the concept is to :

activate the needed passes in the render layers section

use nodes to separate the different passes

This opens a lot of possibilities, because you can independently tweak every passes, export each ones to different locations, if you have just one parameter to modify, it doesn't need to re-render everything, etc...


how can i start blender 2.8 in ubuntu 18.04

The version you downloaded might not be configured for your distribution. To see if there were some error messages you can open a Terminal window in the folder you extracted blender to by right clicking in the file browser and choosing "Open in Terminal". Then run the program by typing "./blender" (or whatever the program file is called), hit enter and see if there are any error messages.

However I would advise to install Blender from another source that has been tested with your OS instead. There is a PPA for newer versions of Blender maintained by Thomas Schiex: https://launchpad.net/~thomas-schiex/+archive/ubuntu/blender
If you don't mind using the newer development version of Blender (2.81) it might be what you want. You can add a PPA to your system by following the instruction close to the bottom of the linked page or through the Synaptic package manager.


Placing text on a curved surface in 360 degrees

3 Solutions!

1. Non-destructive method

Add a curve "Circle"
Add a text object and edit it to represent the text, font and size
Set it to Vertical alignment to center, to have the text align at it's center along the circle

Select the curve and adjust the Resolution U of the curve to a reasonable high value to get a smooth text later

With the curve stil selected, go in edit mode and press Ctrl+T
You can now move the mouse to change the tilt of the curve, kinda like how the street is tilted in sharp curves in car races.

The arrows show the direction of the curve, so it may be that you need to switch the direction if your text ends up upside down. For that go in "Segments" -> "Switch Direction".
Go in object mode and select the text object
Add a solidify modifier, this will allow you to use different materials for front, rim and back faces (if you don't need this, just use the text objects "Geometry" -> "Extrude" parameter)
Add a curve modifier and select the circle as target, the axis should be set already to "X"
Now we need to add a heavy modifier to make sure the text will be smooth and not glitchy from the bending, the Remesh modifier. Once the remesh modifier is added, move it between the solidify and curve modifier!
Set the remesh modifier to "Sharp" mode, then the "Octree Depth" will need to be increased til you are happy with the result.
BE careful though, the higher the value the more your machine will have to work. A value of 9 or 10 gave me the best result, while i would go with 9.

It should look somewhat like this:

A little advice, this method is for an as clean as possible (to this point non-destructive) result and it's heavy on the machine, so saving first is highly recommended.
For boolean operation you will need to convert the text into a mesh though.

2. To generate something more like in your first picture:

Everything up to step 8, then:

In the text object set the fill mode to "None", this will make the text disappear, don't worry, soon we'll see it again
With the text object selected, go in the "Object" menu and use "Convert to"-> "Mesh from Curve/Met/Surf/Text"

Now with only the outline of the text, add a shrinkwrap modifier to the text and select the knob, activate the "On Cage" visual helper (4th right to the shrinkwrap modifier name) and it should look something like this (that knob is just a placeholder based on the first picture)

Step 11 and 12 can be left out, if the text is close enough to the surface by tilting the curve, otherwise it helps to make the text stick as close as possible to the knob geometry.

Go out of edit mode and apply the shrinkwrap modifier
Go back in edit mode and press A to make sure all the text objects elements are selected
Go in object mode and first select the text, then the knob while holding Ctrl thus having the knob as active (brighter outline)
Go in top view, then toggle back in edit mode
Go in the "Mesh" menu and use "Knifeproject"
You should now have the text/numbers cut in the geometry/mesh of the knob and can adjust your camera to a view you like again

Deactivate the text object and make sure that the knob object is selected
Back in edit mode
The result usually leaves you with the faces of the cut text
selected, i recommend to go over the result and correct eventual
problems, as it seems to never be 100% clean, after that...
Press RMB and select "Extrude Faces Along Normals" to push the text faces in the knob and get the engraved look

To get cleaner results, use a higher subdivided knob to knifeproject on.

3. And lastly (should not be forgotten, even if we like to build everything in Blender) using a texture you can safe yourself a lot of heavy geometry:

Select the faces of the ring-section on your knob make sure they are kept as a circle, marking inner and outer loops as seams for circular shaped surfaces helps.
To get the best results for the situation at hand, i created the 3 flat surfaces like mentioned and broke up the borders with one cut/seam each, resulting in a rolled out stripe and 3 circular parts like in the picture below.

Note: Donating more texture space to certain surfaces of a mesh can in this case ensure the best resolution where it's visible, as the rest is pretty much just color, but in case borders of the surface need some details, you may need to ensure that at least the affected islands (UV-map parts representing the surface) are scaled equally (for example island 1, 4 and 5 as they would otherwise become blurry towards the island 4 and 5 due to lower resolution given to them).

You can export the unwrapped UV-Map as template for the Numbers to fit on
Create the Text/Numbers arranged in a circle in a program of your choice
Numbers in black, background in 128,128,128 grey (medium value) saved as .png
Use the .png file as (non-color/raw) texture and use it for the bump/displacement (displacement best with either high subdivision on the knob, OR if you use cycles you can go experimental and activate "Adaptive" in the subdivision modifier, which gives great results without you having to increase the subdivisions too high. You may only need to adjust the "Dicing scale".

Here a Screen full with the essentials for the texture approach:

Top left: UV-Map exported

Top right: Evee render

Bottom left: Bump/Displacement texture generated with Inkscape

Bottom middle: UV-map above the texture

Bottom right: Shader for the knob, using both bump and displacement (cycles/evee output) as well as color from the one texture.

Might be better to read.

Fine tuning is fun each should have for themself ;)


Sorry but you forgot to press Use Nodes button in material setup panel:

Metal cannot have Emission
Your Shader Node has white emission value


Extrude Individual Polygons Proportional to Polygon Area

Here's a bmesh script with adjustable factor (in redo panel):

import bpy
import bmesh

def main(self, context):

    me = context.object.data

    if me.is_editmode:
        bm = bmesh.from_edit_mesh(me)
    else:
        bm = bmesh.new()
        bm.from_mesh(me)

    ret = bmesh.ops.extrude_discrete_faces(bm, faces=[f for f in bm.faces if f.select])

    for f in bm.faces:
        f.select = False

    for f in ret['faces']:
        f.select = True
        vec = f.normal * f.calc_area() * self.factor
        bmesh.ops.translate(bm, vec=vec, verts=f.verts)

    #bm.normal_update()

    if me.is_editmode:
        bmesh.update_edit_mesh(me)
    else:
        bm.to_mesh(me)

    #me.update()

class SimpleOperator(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "mesh.extrude_faces_indiv_area"
    bl_label = "Extrude Individual Faces (area-proportional)"
    bl_options = {'REGISTER', 'UNDO'}

    factor = bpy.props.FloatProperty(name="Factor", default=1, soft_min=-100, soft_max=100)

    @classmethod
    def poll(cls, context):
        return (context.object is not None and
                context.object.type == 'MESH')

    def execute(self, context):
        main(self, context)
        return {'FINISHED'}

def menu_func(self, context):
    self.layout.operator(SimpleOperator.bl_idname, text="Individual Faces (area-proportional)")

def register():
    bpy.utils.register_class(SimpleOperator)
    bpy.types.VIEW3D_MT_edit_mesh_extrude.append(menu_func)

def unregister():
    bpy.utils.unregister_class(SimpleOperator)
    bpy.types.VIEW3D_MT_edit_mesh_extrude.remove(menu_func)

if __name__ == "__main__":
    register()

Note that it's pretty slow unfortunately :(

I worry this comes from the translate op for each face (or vec calculation?), don't think this can be made much faster.


How do I remove parts from my 3d printing file?

select vertex of part you want to keep
select linked by L
invert selection Ctrl+i
delete X


I don't know if I was blind before, or if this was added with the latest update I got (2.82.7), but now on Preferences->Display there is the "Large Cursors" checkbox (and there's also the Line Thick picker). So problem solved.


Add-on UV Paste Copy/ Align Distribute and Screencast in Blender 2.72

I don't know about UV Copy/Paste addon, but Screencast have been removed indeed.
Still, there's nothing against using it, just install it manually - download source file and install from file:

Screencast wiki page

UV Copy/Paste


you could you use this addon:

https://github.com/Radivarig/UvSquares

it is made for this specific purpose. While the addon is free you can consider supporting the developer if you like and use it:

https://blendermarket.com/products/uv-squares/

for how to use it:
https://www.youtube.com/watch?v=VYZnGIql2UI


Solved it:

(prev_edges -> edges from previous cone)
c = bmesh.ops.create_cone(my_bmesh)
verts = list(c.values())[0]
curr_edges = verts[0].link_faces[0].edges
total_edges = [e for e in prev_edges] + [e for e in curr_edges]
bmesh.ops.bridge_loops(my_bmesh, edges=total_edges)
prev_edges = verts[-1].link_faces[0].edges


Cloning objects to multiple locations in Sverchok

Inspired by some examples elsewhere, here's my best attempt so far, but it doesn't (yet?) solve the problem of setting A and C to a different scale from B and D...

...but as far as it goes, it looks a bit tidier.

EDIT:

Right, so, with Kabu's help, the inclusion of a 'simple?' List Input has solved the next part of the puzzle. Very neat - although Kabu has suggested that there is room for further optimisation as consequence of redundancy!!

(https://blend-exchange.giantcowfilms.com/b/JoWGSlO7/)


solidify modifier is distorting parts of the model

The fastest way to fix this is probably just to split the blade and the hilt, and apply solidify to only the blade.

To split the blade from the hilt, go into edit mode with the sword selected, then click anywhere on the blade and press ctrl+l, which will select all linked.  If this selects the hilt too, you will need to select the faces manually.  Once you have the blade isolated, press p while still in edit mode, then choose "selected".  This will break the sword object into a hilt object and blade object.

From there, you can just apply solidify to the blade as you did before.

From a 3D printer perspective, you may want to not print the blade at all, and make it yourself with plastic sheets from Hobby-Lobby or something.  3D printers have some trouble with long and thin.  Not to mention you will save money from avoiding printing costs.


How to render only visible object without using layering or doing some cumbersome steps?

To render only some objects in viewport you can just go to the local view of the object by press /. To hide objects in render mode, just select the objects to be shown in the render or select the objects to be hidden from the render and press CtrlI to invert the selection (remember that objects to be hidden should not be selected) and then press W then select Restrict render unselected. Thus any unselected objects wont be rendered. To remove this, press W and press Clear all restrict render.


Can rigid bodies interact with fluid domain?

Fluid simulations and rigid body simulations cannot interact.

Fluid simulations can react to rigid bodies, if the rigid body is a fluid obstacle. Set your falling objects both as fluid obstacles and rigid body active objects. A key setting is to check "Export Animated Mesh" in the fluid settings of the active rigid body object. This 2.68 tutorial should work fine in the newest 2.78.

The rigid body can be simulated beforehand or during playback and will not be affected by the fluid (the fluid can't push an active rigid body around).

However, in your case I wouldn't use this, because:

The motion of falling raindrops is very simple, it can be easily done with keyframes
As Duane Dibbley commented, the whole ripple-effect could be easier with dynamic paint
Rain is not a rigid body... If you wanted maximal physical accuracy, the rain drops should be fluids as well.
Particle systems are also not rigid bodies, it can be tricky to combine the two.


How to only deform (GKEY in Edit Mode) selected faces?

You can hide (H) the vertices you don't want to move. They won't be affected by the PET.

To make them appear again, unhide them with Alt+H.


Config blender to save backup files in subfolder

I took a little time writing an addon for Blender, which will move the backup save files to a sub directory every time you save. You may change it however you want it to work.

I hope it works for you guys. :)

Simply save the code below into a file called something .py, I called mine "blender_move_backup_save_files_to_a_sub_directory.py".

Then import the file by clicking: File > User Preferences > Addons > Install From File... > Finally select the file and activate the addon.

bl_info = {
    "version": (1, 3),
    "blender": (2, 68, 0),
    "name": "Move Backup Save Files To A Sub Directory",
    "author": "Jonathan Stroem",
    "description": """Move the backup save files to a sub-directory instead of the Blender-file's current directory. A new folder called "backup.blend" will be created and all save-files will be moved there instead of the default folder.""" ,
    "category": "System",
    "location": """The backup folder will be named "backup.blend". Under 'File > User Preferences > File > Save Versions', you can change how many backups that'll be used.""",
    }

#IMPORTS
import bpy, os
import shutil
from bpy.app.handlers import persistent

import time
from stat import *

#When enabling the addon.
def register():
    bpy.app.handlers.save_post.append(move_handler)

#When disabling the addon.
def unregister():
    bpy.app.handlers.save_post.remove(move_handler)

#So that Blender recognize it as an addon.
if __name__ == "__main__":
    register()

@persistent
def move_handler(dummy):

    #fullpath = Full path to the data file.
    #directory = Directory the data file is in.
    #name = Name of file, without extension.
    #extension = Extension of files.
    #backup_amount = Max amount of backups to store.
    #backup_directory = The name of the backup directory. (Where the files should be moved.) So change this if you want to change where the backups are saved.

    file = {"fullpath":bpy.data.filepath, \
            "directory":os.path.dirname(bpy.data.filepath), \
            "name":bpy.path.display_name_from_filepath(bpy.data.filepath), \
            "extension":".blend", \
            "backup_amount":bpy.context.user_preferences.filepaths.save_version, \
            "backup_directory":"backup.blend" \
            }

    #Create backup directory if it doesn't exist.
    if file["backup_directory"] not in os.listdir(file["directory"]) :
        os.chdir(file["directory"])
        os.mkdir(file["backup_directory"])

    #Get current save files from the backup directory.
    currentFiles = []
    for f in [ f for f in os.listdir(file["directory"] + "\\" + file["backup_directory"]) for c in range(1, int(file["backup_amount"]) + 1) if f == file["name"] + file["extension"] + str(c) if os.path.isfile(os.path.join(file["directory"] + "\\" + file["backup_directory"], f)) ] :
        currentFiles.append(f)

    #All this is moving the correct file.
    if len(currentFiles) < 1 : #If no files, then no need to check.
        if os.path.isfile(file["fullpath"] + "1") :
            shutil.move(file["fullpath"] + "1", file["directory"] + "\\" + file["backup_directory"] + "\\" + file["name"] + ".blend1")
    else : #If the max backup amount has been reached, then check for the oldest file and overwrite that one.
        if file["backup_amount"] <= len(currentFiles) :
            replaceFile = {"modified_date":None, \
                           "fullname":""}
            for f in currentFiles :
                stats = os.stat(file["directory"] + "\\" + file["backup_directory"] + "\\" + f) #Get attributes from a file.
                if replaceFile["fullname"] == "" : #This will happen only the first time.
                    replaceFile["fullname"] = f
                    replaceFile["modified_date"] = time.asctime(time.localtime(stats[ST_MTIME]))
                else : # Is the previous file older or newer? If it's older, then you'd want to overwrite that one instead. Go through all backup-files.
                    temp_modified = time.asctime(time.localtime(stats[ST_MTIME]))
                    if replaceFile["modified_date"] > temp_modified :
                        replaceFile["fullname"] = f
                        replaceFile["modified_date"] = temp_modified

            #When the loop is finished, the oldest file has been found, and will be overwritten.
            shutil.move(file["fullpath"] + "1", file["directory"] + "\\" + file["backup_directory"] + "\\" + replaceFile["fullname"])
        else : #If the max backup amount hasn't been reached, and the folder isn't empty.
            #Then check for the next number, and then just move the file over with the correct number.
            replaceFile = "" #Location.
            for f in currentFiles :
                for c in range(1, int(file["backup_amount"]) + 1) :
                    if not os.path.isfile(file["directory"] + "\\" + file["backup_directory"] + "\\" + file["name"] + file["extension"] + str(c)) :
                        shutil.move(file["fullpath"] + "1", file["directory"] + "\\" + file["backup_directory"] + "\\" + file["name"] + file["extension"] + str(c))
                        replaceFile = f
                        break
                if replaceFile != "" : #File to replace has been found, break out.
                    break

#This document is licensed according to GNU Global Public License v3.


What are the new 3D cursor features introduced in 2.73?

This feature is added by the Enhanced 3D cursor addon it is best to read it's rather long usage entry to learn about it's functionality.


Nevermind.
Viewport overlays > sculpt > face sets slider / toggle.
Found it.


Method to align object local axis with global plane when rotating on local axis?

Select the cube, Shift S > Cursor to Selected, choose 3D Cursor as current pivot point, or simply press . (the period key).
Press Numpad 1, add a plane object, press F6 then toggle Align to View, in order to make it parallel to global XZ plane.
Select the cube, then View > Align View > Align View to Active > Top (or simply press Shift Numpad 7), then add another plane object, toggle Align to View in F6 panel, as well.
Keep current View unchanged, add an empty object, toggle Align to View in F6 panel, as well. G X X to move a certain distance along its local X axis.
Add a Boolean modifier to either one of the plane, set Boolean mode to Intersect, choose another plane as the target object, in order to generate the intersection line from two planes.
Enable Snap icon on 3D View header, choose Edge as snap element, and Active as snap target, first select the cube, then select the empty by holding Shift to make it active, R Z Z, move mouse over the intersection line generated in Step 3, until it is snapped, LMB or Enter to confirm. Finally, delete these extra objects.


Dyntopo: Re-symmetrize only part of mesh

Best bet is to do all your mirrored sculpting first,
then turn mirror off, and finalize asymmetrical details.

For instance:  https://www.youtube.com/watch?v=TLb_CCoWn5o

If you've already started sculpting without symmetry,
it's possible to copy your sculpture, then place a cube around the area.

Use boolean modifier set to intersect on one sculpt & cube,
Use boolean modifier set to difference on the other sculpt & cube.

Continue sculpting on the area that only has symmetrical details.

Merge the two halves with a boolean union once you're finished,
and smooth any seam with the sculpt tools.


White Image appearing grey when saved as RGBA

So after much trial an error, I was able to fix this by changing the exposure value from 0 to 1 in the color management tab.
This was the only way I could get my RGBA image to appear pure white, like the RGB image was.
Thanks guys


This is called stair-stepping, or the staircase effect.  It's the lack of anti-aliasing causing this effect.


Right click on the left side of the header where the menu entries are and select Flip to bottom


getting started: no module called bpy outside of Blender

bpy is only available when a script is being run from the Python interpreter in Blender. You can't access it from an external interpreter. The bpy module itself is located in the Python environment supplied with Blender (if you download the zip-file, rather than the installer).

To use the bpy module, open the script in Blender's Script Editor.


GG can actually extend edges beyond existing bounds.

Either: drag slightly inwards to establish the edges you're sliding along, and then hit C or hold Alt while dragging outwards along the (now displayed) extended edges,

Or Go into the 'Adjust Last Operation' panel, and uncheck 'Clamp'

It's always worth checking operator options displayed at the bottom of the 3D View when you're getting to know new tools.. I'm still picking stuff up from there, even after using Blender for quite a long time.


You can either scale the whole sword in object mode by selecting it and pressing S > X to scale along the X axis or,

If you prefer a little more detail select your sword, go into edit mode with Tab key, select only the faces corresponding to the blade part, and scale them along the X axis with S > X.

If you go with the first option of scaling in object mode don't forget to apply the scale afterwards by pressing Ctrl + A > Scale when you're done.

P.S. Scaling (and other modal operators in Blende) use the cursor distance to the center for the screen at the moment of invoking the operator for precision factor, so make sure your mouse is not too close to the center when calling the command or you may end up with an overly sensitive scaling factor that may yield weird results as in your second image.


Baking smoke is very similar to baking fluid, so I will quote brecht's answer:

  It's a bit more complicated than it could be because fluid simulating baking is only exposed as an operator. That means it expects an active object in the context, which is usually provided by the user interface that is not available in background mode.

However, it is possible to override context manually, see the api docs.

So for a smoke simulation:

import bpy

for scene in bpy.data.scenes:
    for object in scene.objects:
        for modifier in object.modifiers:
            if modifier.type == 'SMOKE':
                if modifier.smoke_type == 'DOMAIN':
                    override = {'scene': scene, 'active_object': object, 'point_cache': modifier.domain_settings.point_cache}
                    bpy.ops.ptcache.bake(override, bake=True)
                    break

This will bake the selected cache for all domain objects in the file.

You can then run this python script in blender with

blender --background /path/to/file.blend --python /path/to/script.py

Or the short way:

blender -b /path/to/file.blend -P /path/to/script.py


How can I solve problems with Remesh modifier?

I guess it's not bug, as the Remesh Modifier page on Blender 2.79 Manual explain this problem and how to solve it :

Just add a Solidify Modifier, set the Thickness to 0.5, and make sure the Solidify Modifier is processed before the Remesh Modifier but after the Ocean Modifier. The order of the modifiers should be, from top to bottom : Ocean / Solidify / Remesh.


Enable this button ("Limit selection to visible")

Also, you must setup more usefull limits here:

The result of "End"/"Start" mast be as low as it possible. Now you have 299621/0.000001=296210000000 - it is very big! Increase the first value and reduce the second, so that the result of the division becomes less than million.


Seams are correctly marked, UV's are messed up

Those lines stretching from an island to another could be caused by a single missing edge mark, or that after doing the UV Map you picked up a couple of tris and turned them into quads and those triangles where from different sets of islands.


Installing sculpting brushes permanently

You'll need to set fake user for all appended brushes and then "Save Startup File".


How to control the strength and intensity of IES lights?

Select the IES lamp in the 3D Viewport and press N to get the properties panel and scroll right to the bottom where it says Lamp Properties and there you will see a strength and color regulator.


I think what you want to do is mix whatever shader you are using for the earth's surface with a bluish shader towards the edges.

To do this just plug both shaders into a mix shader (like you already have), with the bluish atmosphere in the bottom socket.  Then control the mix factor with a Fresnel node.

]


Python Function to Discover Triangle Slope

Okay, here's a start:

import bpy
from mathutils import Vector

a = Vector((..., ..., ...))
b = Vector((..., ..., ...))
c = Vector((..., ..., ...))

ab = b - a
ac = c - a

normal = ab.cross(ac)
normal.normalize()

# assuming Z is up
slope_dir = normal.xy

# Heres 3 methods you could use to measure slope amount...

# measure xy length (0-1) where 1 is flat.
slope_amount = slope_dir.length
# so you can tell if the slope points up or down...
slope_amount = slope_dir.length * (1.0 if normal.z > 0.0 else -1.0)

# use normal z axis, 1.0 will be up, -1.0 down.
slope_amount = normal.z

# measure slope angle (0 - pi) where 0 is flat.
slope_amount = Vector((0.0, 0.0, 1.0)).angle(normal)


How do I make my transform values match up to the ones on the Object Properties window?

The pop up shows the transform relative to starting position. The object properties shows absolute position, relative to grid. If you want to change absolute position, just use the object properties panel and type in the values you are after.


Making a curved tube thinner or thicker without scaling its overall size

Yes, in edit mode you can use Alt+S to scale along vertex normals instead of from the median point.

So you can scale this...

To this...

To this...

This also works for bezier curves as well, even without converting to mesh.


How do I create texture that resembles texture of human body?

Since it seems you found it useful, I am re-posting my comment as an answer:

For the dimpling use a combination of a Displace Modifier and some bump in your material. For the skin material add an SSS Shader to your glossy+diffuse mix. A skin texture image into the Diffuse color input would help too. For the ripple you can use a Cloth sim like in this tutorial. or a Soft Body sim like in this tutorial. Finally here is a Soft Body tutorial specifically for belly ripple, lol - although it is in Spanish. Good luck!


What is causing pinching artifacts in this mesh?

That is caused from the triangle fan at the bottom of your cup, and the subdivision surface modifier.

To fix it delete the vertices at the center of the bottom of the cup.
Select the edge loop along the bottom, press E to extrude then S to scale it smaller. Repeat that three times, and for the last time scale to 0. Then remove doubles.

This is how it will look after extruding and scaling three times. This will give  acceptable results when using a subdivision surface modifier.


Add object constraint to a number of selected objects

With the objects selected, add the desired constraint to the active object.
From the 3D View header menu choose Object > Constraints > Copy Constraints to Selected Objects.

All the objects will now have the same constraint.

This method doesn't require an add-on to work.


I have a problem with my lighting and shadow

The second screenshot shows a correct preview, since Scene Lights and Scene World are enabled. If Scene World is disabled, an HDRI is used to light the scene preview. With Scene Lights off, your point light is ignored, hence the wrong shadow. The options are explained in the manual.

  Scene Lights

  Use the lights in the scene when rendering the scene.

  Scene World

  Use the world of the scene when rendering the scene. When turned off a world will be constructed with the next options.

  HDRI Environment

  The environment map used to light the scene.
  Rotation

  The rotation of the environment on the Z axis.
  Strength

  Light intensity of the environment.
  Background

  The opacity level of a very blurred version of > the HDRI will be rendered as background in the 3D View.


You can use the Set Alpha node found in : Add➝Converter➝Set Alpha use the mask node  output as an Alpha input for the Set Alpha node :


Change of the color of the hair in a render video

You can get a MixRGB node, plug it into the color of your shader, slap a color ramp on the factor of the MixRGB and put a gradient texture on the factor of the color ramp. Slide the colors around in the color ramp and you get a nice transition. :D


Sounds like you have some kind of snap setting on. Look at the snap (magnet) icon in the top,center of your 3D view. Make sure it is off.


Apart from smoothing the mesh with Subsurf,
you could also try adding a Bezier Curve Modifier to the Geometry of the Line Style:

Before:

and after:

You can also tweak the result by adjusting the chain angles:


With the texture displayed in the UV/image editor, press AltR or Header > Image > Reload image:

There is also a refresh button on the source selector for any image datablock. In the node editor, the full datablock settings are in the Properties region. To reveal this region, place your mouse over the node editor view and press N:


Please explain logic of this transparency material nodes

This seems to be some form of crude "Wipe" effect.
By using the object's local Z coordinate as input and running through the Less Than math function it basically makes an horizontal line mask.
In the vector node the X and Y axis Scale value to zero is turned down, which makes it basically output the pure Z axis, as opposed to all axis at once which would give a 45º tilted angle. This has basically the same effect as using a Separate XYZ node.
By linking it to transparency it basically makes the object opaque or transparent above/below a certain Z value defined in the Less Than node.


Since you are using a single object, you have to enable Self Collision to allow parts of itself to collide with itself.

However, you will need a lot of accuracy and samples. The situation of many rigid pieces would be better suited with a Rigid Body Simulation.


Like many (most?) things in Blender there are multiple solutions to any problem, and this challenge is no different. The decision on which method to use will largely depend upon underlying geometry, you need, what you plan to use the project for, what future use you might want to make of the geometry later, and at what stage you are at in the development of the project.

I've actually modeled bits of terrain where I was modeling actual parts of the US. The technique I like best so far is to start with a "circle" with four vertices, subdivide the edges, so that there is one vertex at each point where a contour line crosses the edge. I then extrude from vertices (or sometimes pairs of vertices, looking elevation to the vertices on the opposite edge. Then I fill the faces. In this method, the retaining wall poses no particular issue; the land above is at one elevation, the land below is at another. Depending upon the nature and construction of the retaining wall, I would either construct it as part of the terrain, or model it later with another object. Whether or not I would merge the retaining wall with the terrain would depend upon a number of factors. I can easily imagine instances where I might combine the retaining wall into the same object as the terrain, but generally would keep it separate.

Ive uploaded a simplified explanation of my general workflow here, along with a ~.blend file that illustrates the various steps. The first step is illustrated in layer 2, the second in layer 3, &c.

In my workflow, I would be unlikely to use a boolean modifier on the terrain, because the workflow I use would simply bypass any places where I would a boolean modifier.


cycle units measurement through hotkey is it possible?

The path to use for the context Attribute is

scene.unit_settings.system

Where you find a class name of UnitSettings is shown with it's name in CamelCase, you will often find a corresponding property that represents it will use the form unit_settings with all lowercase and underscore separating words.


Where can I change the settings for UV unwrap?

When you unwrap, at the bottom of the Tool Shelf accessed by pressing T or press F6 to bring up the popup.


The easiest way is to select your Meta-Rig and go into Edit Mode - select all the bones and scale to your Mesh size. You could also do the same thing in Object mode, with one additional step - applying the scale with CTRLA

This answers your question - below is just extra stuff that may be helpful...

The scale should by default go towards the Median point - which is that little orange dot which identifies the root of your object. At the moment your Mesh object and Meta-Rig object have different positions for the Median point. Best practice is to get them aligned. You can do this by selecting your Meta-Rig in Object mode and ShiftS Cursor to Selected. With the position established now select your Mesh in Object mode and move the Median point to the same location...

Now you can return to your Meta-Rig in Edit mode and start positioning the bones...


Im New to blender and I found an easy way: (first time ever in blender)

-Open blend file

-open uw window

-in the icon with a photo , search for the textures

-once selectes just click on the file button

-export it


This happens because many vertices in your mesh are not assigned to any bone so they don't deform.

These steps will solve your problem:

select your mesh
while selecting the mesh hit shift + RightClick to select the armature as well
hit Ctrl+P then choose automatic weighting

This will solve the problem as shown below:


How do I mix two bump nodes and fade from one to the other?

Your chosen route is to mix two shaders, each shader with its own normals, generated from heights, using Bump nodes.
Mixing Shaders is, as far as I know, gathering contributions from each shader, biasing samples made by the renderer, in Cycles. In EEVEE, I'm not sure.  In particular, I don't know how normals are combined. Maybe someone who knows can help with that. Mixing normals is tricky: they represent directions; just mixing the colors that encode the directions won't do.
Why the ramble? Because, however that's done, mixing heights is easy by comparision. It's just an addition.
Personally, using the 'Node Wrangler' shipped-add-on's convenience, CtrlShift-clicking nodes to preview their output as I went along, I would ..

Preview the Wave and Noise textures, and try them out through Bump on their own, on a neutral material. I would put whatever was needed around them (perhaps Color Ramp / Multiply) to adjust the heights, before they get to  the Bump node.
Preview the Gradient, on its own, to make sure it was oriented correctly, and roughly right.

So the resulting chunk of tree would be something like this:

What's in those 'Adjusted' groups will depend on how you want your waves and noise to look. The Multiply Add  is just my choice for changing the width and location of the gradient.
The only suggestion is that it's easier to mix heights, here, than shaders, or normals.


How can I get a shape with a emission node to be brighter in the center?

Create your text "Bar"
Duplicate it
Extrude both text meshes
Make one skinny and one fat
Change the offset of the "skinny" one to a negative number and place it inside the "fat" one.
Add a emission shader to the "skinny" text. Set it to 3 or so.
On the "Fat" text add a translucent shader.
(optional add another material to the extruded part like the picture.)


can I render some elements the way they look in material preview and how to do it?

First, you can do it in the 3D Viewport only. Find a View menu, and click the Viewport Render Animation. It will render the animation right from the viewport, using EEVEE if in solid or material preview mode. If you disable screen overlays, you can easily get nice renders in EEVEE this way, however, this is limited and inaccurate (not enough screen samples will be used, and softshadows can be blurry and flickering, among other limitations).

Here is the place where you can find View menu:

And then, find this menu command:


ReMeshing two vertex groups to different resolutions

you could always seperate the mesh (select the ear in edit mode, hit P and seperate based on selection) then remesh each object individually, apply the modifier, and then join (and manually stitch or use bridge if possible)


Why does my blender 2.8 not recognize the gpu?

The Radeon R5 M430 has the GCN first generation micro-architecture and is therefore not fulfilling the minimum requirements for GPU rendering.

  Modell: Radeon R5 M430[158](Exo Pro)

  Launch: 15 May 2016

  Architecture: GCN 1st gen (28 nm)

Requirements for GPU rendering from the manual:

  AMD

  OpenCL is supported for GPU rendering with AMD graphics cards. Blender supports graphics cards with GCN generation 2 and above. To make sure your GPU is supported, see the list of GCN generations with the GCN generation and supported graphics cards.

  AMD OpenCL GPU rendering is supported on Windows and Linux, but not on
  macOS.


How to apply a png texture over my material?

I suspect you are looking a way to use "MIX SHADER".
check this settings:

add a MIX shader node and as inputs 2 principled BSDF (one for the plastic look, one with the texture)
as factor as MIX shader use the Alpha channel of your image
fix the UV map if needed..

Suzanne is now happy:


In 2.80 all things that displays on top of the renderable objects calls overlays. You can edit what do you want to display in viewport in this Overlays popover:


Bone.008 does not respect naming conventions for mirroring:

Names on right part should finish with ".R" or ".Right" (for instance) to be recognized when parenting to bones.
In more details, the documentation:

Examples of valid separators:
(nothing): handLeft –> handRight

“_” (underscore): hand_L –> hand_R

“.” (dot): hand.l –> hand.r

“-” (dash): hand-l –> hand-r

” ” (space): hand LEFT –> hand RIGHT


video quality loss after exporting blender vse

I have noticed that sometimes youtube get finicky about its actual resolutions it uploads and can be inconsistant if you dont fit to their resolution standards (sometimes it works, sometimes it doesnt).

As in, resize to 2560 x 1440 and try uploading then... List of supported resolutions is here -- https://support.google.com/youtube/answer/6375112


How can I scale a subsection of a mesh created with the screw modifier?

If you are trying to adjust the Curve path in this case, you can follow this way:

Tab into the Edit Mode, select one or more points on the curve;
Then press AltS to loosen or narrow it as you want (or click Scale Feather button in the Toolshelf).


Particle origin when particle is a group

Alternative 01. If you want a whole group to behave as one leaf.   duplicate the leaves ... then [Join] the new meshes into one single mesh.  You can change the origin of a single mesh in edit mode.

Alternative 02. Deselect [Whole Group] if you want your leaves separate.

When this is done increase the number of particles and bring image in 3D View up to date and inspect.  Increase or Decrease the number to suit your needs.


Based on your script you appear to be using Blender 2.80. The following may help to address some issues. Blender 2.80 allows for multiple objects to be in edit mode at the same time which is not strictly addressed in the below but the script only acts on the active object in the event multiple objects are selected in edit mode. previously your script could break if run in object mode causing obj = bpy.context.edit_object to be None type and me = obj.data to fail check was added prior to function call.

import bpy
import bmesh

def delete_faces():
    obj = bpy.context.active_object
    me = obj.data
    bm = bmesh.from_edit_mesh(me)
    sel_faces = [s for s in bm.faces if s.select]

    sel_mode = bpy.context.tool_settings.mesh_select_mode[:] # define active selection modes

    if sel_mode[2] == True:  # if polygon selection mode is on
#        bmesh.ops.delete(bm, geom=sel_faces, context=5)  # bl 2.79
        bmesh.ops.delete(bm, geom=sel_faces, context='FACES')  # bl 2.80
        # deselecting edges is not needed use FACES_ONLY if that is the desired effect
        # ('VERTS', 'EDGES', 'FACES_ONLY', 'EDGES_FACES', 'FACES', 'FACES_KEEP_BOUNDARY', 'TAGGED_ONLY')
        bmesh.update_edit_mesh(me, True, True)

if bpy.context.mode == 'EDIT_MESH':  # ensures both edit mode and mesh type before call
    delete_faces()


There is a check box in the material settings tab of the properties window, called "Backface Culling".  Simply uncheck that box and your object will render both sides of the faces in the game engine.


Is it possible to see Vertex Weights in Edit Mode in the 3D View?

It looks like you have the exact same thing in 2.8, but to see the weight for the selected vertex you first need to assign it some weight, either in Weight Paint mode or with the Assign button under the Properties panel > Object Data > Vertex Groups list. As Robin says: The panel is displayed only when you have a vertex which has been assigned to a vertex group selected, even with a 0 weight value.

To see both the wireframe and the weight you can enable Vertex Group Weights in the Viewport Overlays.


Modeling a terrain accurately from a contour map

Assuming your landscape is a mesh, you may try the following:

add a plane a little bigger than your landscape, and at the base (or lower than) of landscape
with plane selected, and under "modifier tab", you add an "array" modifier. You set to constant offset, X and Y to 0, Z to a distance that suits your needs, and you should increase the count to get as much planes as you need to cover the top (or pass a bit) of your landscape). If your landscape is in "real" scale, you can set the Z to 10m, to get the 10m isocontours.
with plane selected, under "boolean" you set to "intersect" with the landscape
apply your modifiers to the plane (you will have horizontal planes by choosen iso Z value)
press "space", write "convert to" and select "curve from mesh/text" (you will convert the planes to lines, to get their perimeter - if you need, you can then increase thickness of lines, etc)
optional step if you want to control the material (colours, etc) of your contours: you  again "convert to" "mesh from curve/text"

Following the exact steps mentioned above you get the following result:


How will Blender work on the Microsoft Surface Book?

I'm using Blender on my Surface Book since several weeks, it runs without any problems and it's very fast. By Preferences -> System -> DPI you can increase the Interface Size. I prefer 140 DPI and everything looks great on the Surface Screen.


How to execute multiple animation node trees over time in a single scene?

Node Trees

Actually when you have mutliple node-trees they both work at the same time, but the most-recently created one overrides the oldest.

This is a completely useless example, but it demonstrates the last created node tree (here 2) will override the z value written by the first (1).

Maybe they are some cool way to make a use of multiple node trees. For example by using booleans:

Cameras

If you are able to check with a script node which is the active camera (if you are using multiple ones), return true if it is one and false if it is the other, you will be able to switch node tree using the animation nodes.

If you are using only one camera, I would suggest you to switch if the Time Info node returns a frame count >= than your angle change:

Here you can see how to use multiple cameras in one scene


Fluid Flow always starts from Domain Boundary Issue

This appears to be a long outstanding issue:

https://developer.blender.org/T28756

and has been added to the "TODO" list at:

https://wiki.blender.org/index.php/Dev:Source/Development/Todo/Tools#Fluid_Simulation

The problem appears to occur when you have a relatively small fluid object compared
to the domain size.

Generally speaking, using an UVSphere as an inflow object isn't a good idea due to the
smaller triangular faces at its "North and South poles".
A less problematic option would be to either use a cube or a level 1 or 2 subsurfed
cube (apply the modifier), if you want to keep the inflow object the same size.

Also, it's good practice to keep all of the fluid simulation elements at a scale of 1
(Your inflow object had a scale of .025, Apply Scale, Ctrl + a > Scale).
(Dimension of 0.05).

Here's your blend file modified using a Subsurfed level 2 cube (subsurf modifier applied)
at the same dimensions (0.05) as the UVSphere inflow object:

Using an inflow or obstacle object that contains faces with even/equal surface area
doesn't guarantee a successfull fluid simulation result when the voxel size approaches
the size of your fluid object(s). In this case, the only option would be to scale
everything up; which can necessitate tweaking any animation you may have on your fluid
objects.


How to save Child Of relative transform to absolute

In the list of keying sets you will find several "Visual" options, these options keyframe values of the visual location/rotation/scale, which is after constraints have been applied.

The only explanation for visual keying I can find is in the keyframing preferences, where you can make this the default behaviour.

  When an object is using constraints, the object property value does not actually change. Visual Keying will add keyframes to the object property, with a value based on the visual transformation from the constraint.


How Do I Make A Perfect Uv Sphere For Water (Not For Equirectangular)

While in Edit mode, select one meridian at your choice. Press "Space" and write down "mark seam". Select one "rectangle" near the equator and connected to the seam you marked, and press "a" to select all, press "u" to bring the unwrap menu and select "follow active quads". You can leave on "length average" and press "Ok". You will get a new UV map with equirectangular projection, with this UV map selected, in the UV Image Editor, adjust the size to match the image, or leave it if the image is tileable.
An easier method (assuming that you are using cycles, and without the need of unwraping) is with a node setup like this:
You can even try to build a seamless procedural sea image your self, and if you really need, bake the procedural image onto a a new image (it will get seamless on your sphere). You can try the following node setup:


On Monday there is this blender live stream on YouTube and I asked in the chat if it is possible to use shape keys as attributes. I got the answer (short version): not yet.
So I guess it will come with the next updates(comment written during 2.92)
Greetings Tobi


Linking object position to another object

If I got it, you can parent the head to some top vertices of the scaled object, like this

first, set the origin of the scaled object to its base face

then select just the top face of the same object

 - then in object mode select the head and after also select the body

then parent and set parent to "vertex"

now, when you scale the body on Z, it will be based on its base, so the top face will move, and the head will follow, as shown above.

here is a test (simplified) file to test


Animate the Fluid's Enabled property:

By right-clicking on it and Inserting Keyframes:


Where to download older Blender versions? Namely Blender 2.80

Here you have all Blender versions
https://download.blender.org/release/


Cancelling extrude still leaves extra geometry

Pressing E is really calling extrude_region_move(), which is a two part operation. It extrudes the selection and then moves it as if you had pressed G.
Pressing RMB or Esc will cancel the move part of the operation, but not the extrusion.

This is actually useful behavior, as it allows you to easily keep the extruded geometry (or loop cut) in place (maybe you want to scale it or something). If you don't want the extruded geometry, you can of course undo it with CtrlZ.

This goes for all two part operations, such as CtrlR loop cut and slide (loopcut_slide).

Note that there are actually one part equivalents for these, but there aren't shortcuts for them (to my knowledge).
If you press Space in edit mode and search for e.g. Loop cut:

Pressing Loop Cut will put you in modal operator for cutting loops, just like pressing CtrlR, but it won't slide them like CtrlR does once the cuts are confirmed (and if they are not confirmed, e.g. by pressing Esc there will be no cuts made at all).


You cannot do this with blender/cycles particles itself but you can use BTrace addon to create animated curves from traced particles:

The addon is still under development but it works very nicely.


Animated tentacle collision / Rigid body not working

Since you're animating them, they don't respond to physics, as earlier mentioned by Mutant Bob.

If you're looking for live animations, separate the tentacles so they can collide with each other. But if you use predetermined animations, this can glitch out on you.

To prevent each tentacle to collide with itself, you have to tweak the settings a bit to increase stiffness and apply self colliding.