You can try to convert the curve to mesh and then just extruding to the shape you want converting the curve to mesh shortcut is alt+C i think  but maybe there is better way how to do it is long time i use blender


You can set the start and end frames of the particles emission in particles setting tab. This can be negative frames (end must be the same or greater than start).


Problem with mesh after using Boolean Modifier

Your using smooth shading. This can be fixed by switching to flat shading or using a bevel modifier.


how can I apply 3 shader by coordinates instead of unwrap UV?

You could test the normal of the surface against (0,0,1) in Object Space.

Assuming 'Top' and 'Bottom' faces are normal to Z in object space..

.. take the absolute dot product of the shading point normal (given
in World Space, so converted to Object Space,) with (0,0,1).
Use ranges of that value as factors in the mixes between your shaders.

EDIT: This tree discriminates by the normal of the underlying geometry. If you want the interpolated (smooth) normal, use 'Normal' instead of 'True Normal' in the Geometry Node.


Your weight paints are probably off. Click on your model, switch to weight paint mode, go to Object data properties panel, and click on the bone causing the problem under vertex groups. Where the problem is occurring, there should be red dots. Change the brush type to subtract and make the color of the red spots causing the problem blue.
Here is where you click on your bone:

Click on the option that has the name of the bone causing the problem.
If you want me to elaborate, just ask.


One object isn't rendering a shadow in Cycles

you just need to select the table and check the "shadow" checkbox under "object properties"


Just by going by the description of your process for inserting keyframes it sounds like you are only creating 1 keyframe.

The process to animate a property is to:

Set the value of the property (in this case the 'Value' property of the shapekey)
Insert a keyframe by pressing I with the cursor over the Value property.
Move to a different frame in the timeline.
Set the property to a new value.
Insert a second keyframe on the property.

Keyframes have to be inserted at every point in the timeline where you want the property to change to a specific value.


Grease Pencil Fill On Surface Disappears At Distance

Grease pencil will only fill at "camera" or current "view" limits left to right and up or down. Else, the application will fill the 3d unlimited workspace forever catching it in a forever RAM eating loop.
What you present in your videos, IS expected behavior to prevent the error I described above.


How can I export a rigged and posed model from Blender to Substance painter without losing the pose?

Apply the Armature modifier in the stack before exporting. Alternatively you can tick the "Apply Modifiers" export setting.


Render pass that output center of object of each pixel

You can do this by using a Material Override and a special material to give the objects' positions.

First create a new material with an emission shader (you can add it to any object, it doesn't matter).  Add an Input > Object Info node and plug the Location into the color of the emission shader.

Now you can create a fake user for the material and remove it from whatever object you added it to.

Then add a new render layer and set the Material Override (under the Layer rollout) to the material you just created.  It would also be useful to override the samples to 1 as well to reduce rendertimes and effectively disable antialiasing.

In the resulting RAW rendered image the red, green, and blue values of each pixel will represent the location of the object rendered on that pixel.


How do I select a set of Blender elements with a common characteristic?

For a mesh in edit mode with

vertex selection see the menu Select Similar.
face selection see the menu Select Similar Area
edge selection menu Select Similar Length
Many other options

Circle Select with the Letter C Selects a circular distance in 2D in many, not all, cases.
To select a ring, first select objects by radius A, then second scroll mouse wheel to smaller radius B, then press Middle Mouse to button to remove the middle.  A minus B (A - B)

Still in mesh edit mode, if you are making a selection repeatedly, consider creating a vertex group for that selection.

Suggestion.  For Objects only.  If you are making the same selection many times. Consider Grouping those objects and thus select group.  Or more drastically create a common parent and select children.


Keep all Animations Nodes instances in one layer

The answer is pretty simple, create a loop and add a Object list for Iterator and connect your object list from the Object Transform Output or whatever list you are using to the iteration, and use the Add > Object > Layer Visibility Output node and connect your Object output to it. and use the Type of "Single" and the number of your layer in the Layer Index, and if you want to keep it on several layers use the Multiple Type and select your desired layers.
Remember that layers have the index equal to the layer number minus one, so, they go from 0 to 19.
Illustrative image:


make "z" toggle between textured mode and wireframe?

It sure is. Just go to Blender's preferences in the Input tab. Search by key-binding: "z". In the 3D View section you will find three "Context Toggle Values" shortcuts, one being assigned to the z key only (no modifier keys). Expand this and change the value of "SOLID" to "TEXTURED".

There is a small yet notable inconsistency in labeling that, in the UI it is listed as "Texture" yet its value name is "TEXTURED" with a D on the end.


How to efficiently merge geometry and get rid of internal shapes, etc?

You could try to merge vertices for a cleaner mesh by enabling the following options:

After that select a vertex RMB and move G displaced vertices over another vertex to merge them a circle appears around the target vertex confirm merge by LMB.

You could also add the reference image as a background image (only visible in orthographic mode).

Method 1
Use extrusion modeling. Extrude single edges E, rotate them R scale them S and if required move single vertices.
This is what @atomicbezierslinger describes.

Method 2
Extrude one single vertex E along the contour of the reference image and add faces later F.


Blender renders HDRI instead of background clip

Ok, turns out this automatically created node was responsible. It's not supposed to be here.

I guess I'm not gonna delete this post for now in case someone else needs it.


How to modify each current's material of a twirl

You can use a ColorRamp to create the pattern.
The Modulo and Divide nodes control the number of Color segments (5 in this example).
Note: You can only use up to 10 segments (you're limited by the Array modifier).


Snap to alignment with other vertices (implicit grid)

I'm not completely sure if I understand your question, but this is how I would go about your example.

  Example: Given a usual triangle, say you want to move the bottom right
  vertex to the top of the triangle (only z). You move that corner
  vertex upwards and once it aligns with the top vertex in the z-axis,
  it would snap to that z-value.

select the bottom right vertex of the triangle;
switch snapping mode to 'vertex, closest, move';
press g to move the vertex;
press z to lock the z axis;
hold control to enable snapping while moving;
move the cursor to the top vertex of the triangle.


Go to File -> Load Factory Settings. It will reset to default layout.

When save this layout by File -> Save Startup File


Changing the shape of a Nurbs Path that's already animated

The answer was simple and I just didn't see it -
Delete the Subdivision Surface Modifier.


export to obj - wrong material names and texture names

In Blender, a "Texture" is a slot that can contain a picture file (or something else, like a procedural, point cloud...). It is omitted when exporting, because in Obj a texture is a picture file. So your first material, mtl001, looks perfectly fine.

Are your sure your mtl002, mtl003 etc are actually assigned to some faces ? (In edit mode, select your material slot, select some faces, hit Assign under the slots list).

Try viewing your cube in Material shading instead of Texture shading, it will show you if the materials are correctly assigned.


Data path for driver: secret of 'node_tree.'

When creating a driver with the property set to material, you're implicitly using a reference to an object of type bpy.types.Material.

Your first attempts in step 2) and 3) didn't work because bpy.types.Material has no attribute called node. The idea in step 4) has the same problem as the previous attempts, because the driver tries to access these attributes in the material object of type bpy.types.Material and since there is no bpy.types.Material.bpy this fails as well.

The correct way to access the nodes is indeed through node_tree since that is an attribute in the object of type bpy.types.Material. It gives you access to all nodes in the referenced material.

Attempt 6) fails again because there is no shader_nodetree in bpy.types.Material.node_tree.

For questions like these you can always consult Blender's Python API docs.


Create a linear brush stroke with weight paint?

This isn't an answer to the question you asked, but it may be helpful in solving your situation.  You can use vertex groups, created in edit mode, named the same as your bones in your armature, to create more precise rigging.

http://www.pasteall.org/blend/36178

You can see what I mean in a quick demo I built just now.


Cycles not Showing Shadows Correctly - Works in Eevee

The answer to this is the "Ambient Occulsion" option in the world settings. If this is switched on, it is displaying the object "incorrectly" from the POV of what I would expect. Obviously, Eevee and Cycles handle AO differently. If anyone has anything else to add I would appreciate it (trying to learn here), but otherwise this was what was the cause of my issues.


how can i make child transformation property to change when its position is changed due to change in parent position

The Transform Panel shows the Local Coordinate Values. Since the Cylinder is parented to the Sphere, what you are asking for is not possible, unless you change the transform panel UI to display world space values (which would require more calculation, I presume)


I'm not 100% sure how the node works, but I think due to the nature of the rendering methods, you will need to bake all of the textures/shading. Here is a tutorial: https://youtu.be/sB09T--_ZvU


Which is the best way to generate 2D mathematical surfaces with a different color each side

The following example accomplishes two things that I believe you want to accomplish based on your question.

Eliminate the seam caused by the one sided surface.
Highlight the twisting contours of the mesh so that the viewer can more easily understand it.

Here is the result:

Here is what I did.  Once I created a mesh that closely resembles your picture, I used the Solidify modifier. The resulting mesh had a squashed seam where the geometry flipped through itself. I then had to apply the modifier so I could delete those faces and reconnect them to fix the seam.

At this point I unwrapped it using the 'Reset' option, so each face filled the texture space. This worked well for the most part, but I had to do a bunch of cleanup. Many of the face normals needed to be flipped and/or rotated 90 degrees. This wouldn't have been as much of a problem if I had used a larger offset in the Solidify modifier. The opposing faces were so close to each other that it was difficult to make selections. In hindsight, I should have unwrapped the mesh before connecting the loop to avoid this problem altogether.

The material is pretty basic. I think the key to getting a uniform texture without distortion is to use the Reset method of unwrapping. However this is only true for tileable textures. I used the Brick Texture here. Checker also works or you could create your own. It may be possible to make an organic texture work using Generated Texture Coordinates, which I tried, but I didn't know how to correct the distortion on the twisted section.

I liked how the Brick texture worked because when you use it as the 'Factor' for a Mix between Emission and Transparency, you can play with the settings so that the texture for each face becomes asymmetric, allowing the grid on the opposing face to become visible. If you really want to impress the ladies, try using a MixRGB node between two Brick Textures.

I settled on this material, because it is pretty simple and just by playing with the sliders in the Brick settings or plugging different inputs from the Geometry node into the Emission strength and color can produce a lot of variety depending on the look you want.


I just had to figure this out myself. If you're on Mac, go to Macintosh HD in the Finder, then you need to reveal hidden folders (Command+Shift+.). This will show the tmp folder. Organize by file type to see the pngs (or whatever file type you saved). Should be there!


How Split Face Normal after 'make edge' between vertex in N-gon

To split the face select 2 opposite vertices on the face and use J button instead of F button, in your case you created an edge on top of the face.


Adding driver through python doesn't work properly?

I think this is a limitation of the current dependency graph.

The way I would handle it is to add a custom property to the object, than add a driver to the array count that uses the custom value, set this other driver to also use the custom property.

As answered in the comments, you also need to overcome the chicken and the egg theory when creating drivers.

Edit

Add a new custom property to the object. in the UI you click the add button, in python there is nothing special, you just give the property a value and it gets created.

bpy.data.objects['Cube']['myControl'] = 1
Add a driver to the count value of the array modifier

Add the same driver settings for the other item that previous read modifiers['Array'].count

Now when you change the myControl value, both items will use the same value. You can create a panel wherever you like to display the custom property or add it to an existing panel.


I just post this to show some error in the weights. I downloaded your file and just reset the pose of all bones (ALT + R)

then selected bone.001:

this bone is not supposed to influence the hilighted area...

there are also many minor errors, maybe just 1 vertex here and there, quite subtle on various bones, but those also "move" your geometry in unexpected ways...


Partial see through material for clothing

What you want to use is a transparency mask! You can do this directly in Blender, or use an image editor, if it's easier. First unwrap your panties, then go to your UV/Image editor and create and save the file at the resolution you want. Remember that file name; it should have appeared automatically in the materials (check all of them if you have more than one), but if it doesn't, you can simply import it manually.

You may have to adjust the setup, anyway. Switch back to wherever you have your node editor open. Once you have your Image Texture with that file you saved (it should be black, but that's actually perfect for this), add a Texture Coordinate node (you'll find it under 'input' in the 'add' menu). Hook the UV slot to the Image Texture's vector slot. From this point onwards, you have a couple of options, as far as setup is concerned. If you're already using a principled shader node, simply plug that right into the transmission slot. (You may have to make it wider to see all the words, so you can find the right one.) If you already have a completely different setup, no worries! Add a transparent shader and a mix shader. Plug your original setup to the top slot, and the transparent shader to the bottom slot. Now hook up your Image Texture to the mix slot.

If you've done everything right, at this point, your panties should still look the same. If they've vanished, or look partly transparent, you've done something wrong (don't fret, if you did, it's easy to do; try zooming in with the mouse wheel and connecting your nodes, and then rearranging them after). Once you have that sorted, make sure you have your Image Texture selected, then go back to where you've been working on your model. Go to material view and zoom in to where you want the panties to be see-through. It's time to switch to texture paint! Make sure you use only a black-and-white brush for this. It can be gray. The idea is all the parts you paint white will be completely transparent, and the parts that stay black will be completely opaque. Gray will mix between the two. To this end, I recommend using a brush with a soft edge to get that gradual affect you're after. As you're painting, you should see it turning transparent under your brush. If you add too much, you can soften or remove it by using gray or black instead of white. Make sure to save your image in the UV/Image Editor before you close Blender. Blender won't do it for you, even if you save the .blend file! You can always pick back up where you left off, if you're not finished, yet.

I hope this helps! Happy Blending!


That is normal behavior. Blender uses a template file, and to create a new document is to reload the template file. From the manual: "New (Ctrl-N): Clears the current scene and loads startup.blend."
Blender 2.79 is not the most recent release, and more recent releases of Blender have changed the phrasing of this menu option and it now gives a choice of templates.
The latest 2.9 release is available here: https://www.blender.org/download/
And the Long Term Support release of 2.83 is here: https://www.blender.org/download/lts/


Retargeting animation with gizmos, delete gizmos in action editor or export without them

After many different approaches I found a solution myself.

To seperate the animations you want, you have to put them in NLA tracks and when exporting to .fbx you must go to animations and uncheck all actions:

It will only export the animations from the NLA tracks

To add animations to NLA tracks you have to open dope sheet -> action editor in one window and NLA Editor in the other. Then you have to select each animation which you want to keep one by one in the action editor and add it to an NLA track on the NLA editor. You have to add them to the armature not the mesh.

Here is how it has to look:


This is a list of possible keying sets: choose one of them (generally LocRot or LocRotScale) and you'll be ok: i.e., if you set LocRot, every time you will click on the keyframe icon six keyframes will be added on every selected element: three about Location (X,Y,Z values) and three about Rotation (again X,Y,Z; four values if the rotation is expressed as quaternion).


use python script as animation node, and give it inputs

Script node works the same way the other subprograms work in Animation Nodes:

Define a subprogram
Then invoke it from another part of the node tree

Let say we have:

a simple text block with some code in it. Here it calculates a string from a list of objects
a group of objects composed here by a cube, a plane, a circle (objects are grouped using CtrlG)

And we want to use the text value of the script to be the text displayed by the text object on the right:

Here in this script 'text' (a string or a text type in AN) will be the result and 'objects' (a list of objects) will be the input.

You can do the following:

Add an object group node. Set it to the objects group's name
Add a text object output node. Set it to the text object.

Add a subprogram as script.
Set its input and choose "object list" as type. Eventually rename the input variable value (here we need to rename it to 'objects').
Set its output and choose "text". Rename it if needed (here we want it to be named 'text').

Add the invoke subprogram node which corresponds to our subprogram's name ("my script" here but you can rename it) and connect input and output of this node.


Why does the mirror modifier create a new object instead of mirroring the object?

this is not a separate object , its just a physically separate mesh, which means that these 2 planes are the part of the same object , this is happening because you object origin is not at the correct place thats why you re getting weird results , you can right click on the object to set origin or in edit mode change the position of the object


Plug the Output of your Multiply Node into the Factor Input of your MixShader. You probably need to invert it before.


InPainting is provided to solve problems like "wire removal" and holes created during chroma-keying as shown in the image here. To make this example clearer, I've used a fake wire (and a fake object) but in reality you'd normally use fine, chroma-keyed wires. This isn't the only way to remove wires of course, but it's a simple one.

You can use motion tracking to do the same thing - the point is when the wire has been removed you're left with a small hole in your frame. For a single image this isn't that much of an issue and could be filled in with Photoshop (later versions have InPainting as part of the healing brush), GIMP, Krita etc.

However, if this is a video you've got 24 - 30 frames for every second of footage and that's a lot of painting. As InPainting is done in the compositor, you don't have to worry, even for long sequences.

In the left image shows the "wire" in place and after chroma-key has been applied you'll see you're left with a blank space - it's shown as a black line here but it will be alpha in your blender output.

InPainting fills in a couple of pixels using the surrounding "background" and voila, your wire is removed. Note that the wider your "hole" is, the more noticeable this effect is! If you use more than a few pixels of infill, the effect is almost as irritating as the wire and your viewers won't be impressed.

As part of this demonstration I've left a little of the chroma effect visible so you can see there's no cheating. Normally, you'd look to get a perfect key.

Inpainting can also cover up a multitude of other minor sins such as control points for motion capture: use it sparingly and it will amaze.


Change the weight of Key 1 to be
 - Full 1.0

The weight must be set to 1.0 to see the full effect.

The value is under the word Relative. It is in  the blender screen capture above.

Temporarily changing the eye icon next to a shape key name may help you to isolate the effects of a shape key and its weight.


Blender Physics constraint implementation sources

The following files contain the implementation of the rigid bodies:

properties_physics_rigidbody.py: UI panels in the physics tab for the Rigid Body
properties_physics_rigidbody_constraint.py: UI panels in the physics tab for the Rigid Body Constraint
rna_rigidbody.c: RNA properties for the rigid bodies.
rigidbody.c: Initialization, copying, validating and freeing data structures for rigid body simulation. Functions for calculating volumes, mass, convex hull. Running and managing the simulation.
rigidbody_world.c: Implements operators that can be called from Python that are related to the rigid body world.
rigidbody_constraint.c: Implements operators that can be called from Python that are related to the rigid body constraint.
rigidbody_object.c: Implements operators that can be called from Python that are related to the rigid body object.
rb_bullet_api.cpp: Wrapper for Bullet Physics functions.

For the parts of code that use the Bullet Physics, search for the WITH_BULLET macro.

Setting the properties and executing the rigid body simulation are separate operations.

Adding a rigid body simulation to an object in the UI results in call to ED_rigidbody_object_add (rigidbody_object.c) which in turn calls BKE_rigidbody_add_object (rigidbody.c). This functions creates the rigid body world by calling rigidbody_add_object_to_scene() (rigidbody.c) in case it doesn't exist and allocates the memory for RigidBodyOb through BKE_rigidbody_create_object() (rigidbody.c) and assigns default values.

For instance the mass property is displayed in the PHYSICS_PT_rigid_body_settings panel (properties_physics_rigidbody.py). It references the RNA property defined in rna_rigidbody.c which calls rna_RigidBodyOb_mass_set() when a new value is assigned through the UI. This stores the value in RigidBodyOb of the object and updates the state of the Bullet Physics through RB_body_set_mass() (rb_bullet_api.cpp).

Adding a rigid body constraint results in a call to ED_rigidbody_constraint_add() (rigidbody_constraint.c). A constraint collection is created if it doesn't already exist. The constraint is created through BKE_rigidbody_create_constraint (rigidbody.c) and added to the constraint collection through BKE_collection_object_add() (rigidbody.c).

When starting the simulation it executes the function BKE_rigidbody_eval_simulation (deg_builder_nodes.cc) which calls BKE_rigidbody_do_simulation (rigidbody.c). It uses the properties for the world, objects and constraints that were previously assigned.

The explanation of the call stack is a simplification of all the operations that happen during configuration and simulation. They are meant as an overview for where certain steps can be found in the code and not a complete explanation of the performed operations.


Blender 2.8: Grease Pencil Fill Brush Not Working

The confusion is caused by the default setting of any new draw brush material where the fill is set to 0.0 alpha which means it is transparent (it makes sense as you'll most often just want to draw a stroke without a fill). Therefore the 'color bucket' click doesn't do anything obvious besides just adding another stroke.

For proper use create a new (fill) material and change the alpha of the fill color to 1.0 or any other value greater than 0. You may want to edit the stroke settings, too, i.e. deactivate it for the dedicated fill material.


It could be linked to the removes doubles treshold. Try to increase it a little to compensate computation errors when making the spin. (Not sure the 360° spin will be a perfect 360)


One possible way to replace your exact mesh profile with cubes (with only outer ones matching the mesh surface) could be cutting the mesh shape from a 3d array of cubes using booleans. Then, you could maybe make it explode, fall, whatever.

A simplified example:

I started with a sphere, which I wish to replace ("destroy") with cubes:

Then I add another object a little cube, then add 3 array modifiers for each axis (X, Y, Z) with fixed count suitable to "contain" the target sphere (here array modifiers are disabled - eye icon)

Here is a detail of the first (enabled) array modifier on X: note that I leaved a little space between cubes using 1.05 as relative spacing.

which seen in perspective appears as

then you enable also Y and Z

Of course the sphere is now inside this big 3d array of cubes

Now if you enable a further modifier on the cube array, a boolean that intersects the target sphere, you get this resulting shape:

as you see the cubes are a little spaced as planned.

Now you can apply all modifiers: since boolean is quite slow, I suggest to first disable it temporary (eye icon), then apply all 3 array modifiers. Only then enable again the boolean and apply it.

After getting the resulting shape, identical to the image above but a real object, you need to make each cube a single object, to let it later explode, fall, etc.

So you enter edit mode, select all, and press P to get the "separate" menu, and choose "by loose parts":

beware this is very slow since geometry is quite complex here, blender will seem to freeze but it's not, let it finish (when the "separate"menu disappears, it's done)

After a few (minutes in my case - crappy old notebook) you get something like this (I've just hidden half of the "cubespheres" to let you see the inside and the outside)

Each of the cubes is an object independent that will fall, explode, move as you expect...

As an example, here is after setting all cubes as active (mesh) rigid bodies, and letting them fall onto a passive (mesh) rigid body plane:


Sort list node is missing in Animation Nodes 2.1.7?

expression sorted(x, key = lambda o: o.name) works well.


I tried Delagone's comment without success,

  Have you applied the scale to your mesh lights?

but later I could fix the problem by also applying Rotation and Location.

I don't know what the GPU thinks the lamps looked like, but without all three transformations applied, the rendered image was wrong in some way.


My blender textures are only visible when in texture paint, but disappear when in any other mode

You can add a new material and apply the texture you painted to it and then you can go to material preview or rendered view to see if it looks good.


How do I animate a smooth texture animation?

Don't animate the "Location," you want to be animating the "Rotation" of the mapping node.


It's not possible right now.

The frame server is implemented in source/blender/blenkernel/intern/writeframeserver.c .As of 2.78c, Blender will only respond with a PPM image, but it looks like other formats can be easily added.


How to automate selection and assembly of clips defined in an input file with builtin functions or (python) scripts

There is an add-on to import EDLs (Edit Decision List), it is a trunk add-on that comes with Blender. As long as your list conforms to the correct source and timecode i don't see why this couldn't work.


Found a solution, which has nothing to do with caching:

The animation displays a PNG image (texture) which will be replaced by particles that then disappear. The image seems to be dissolving.

To change the image dynamically, a Python script assigns a new PNG to the texture, with bpy.data.textures['Logo'].image = IMAGE.

What was missing was to also update the texture for the particle emitter. This can be done as follows in Python: bpy.data.particles['ParticleSettings'].active_texture.image = IMAGE

Without updating the particle emitter, the visible image would change, but the particles would still emit from where the old image was.


How to create a glowing object in a light background?

You will need to have something dark in your image to make the glow work. It needs contrast or it will look washed out. You have made your rings black and you could try to make the nucleus light up those. That could make the nucleus appear to emit light.

Maybe something like this?

Here is the material node setup for the glowy thing in the middle.
It can be applied to any object larger than the falloff radius.
It controls how mush light that should be emitted by the volume by creating a gradient from the objects center and out.


Is it possible to disable self casting shadows on a mesh but still receive and cast shadows in eevee 2.9?

for eevee use this node setup:

important: this works only with:
Blend mode: alpha blend
Shadow mode: alpha hashed (none works too)


Nothing will unwrap, even after applying seams

Choose the UV Editor, not the Image Editor, or choose Paint mode instead of View. Also, use U to unwrap, not E.


Texture problem with Makehuman model in blender

UV map is a coordinate system that helps to wrap a 2D image around your 3D object.
You can read a little about UV's here http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/UV_Map_Basics

Here is your situation.

What you see in white is your texture, exported from Make Human. The wires you see are your UV map. To look good they must match. I don't know how you ended up with sweeter when your character in Make Human had T-shirt, but I think this is your problem.

To fix it you need 1 of 2. Either edit your UV's to match the texture or edit your texture to match the UV's. You can read about the first way in the link I gave you, and you can edit the 2nd in any image editing software.


Image texture is not applied on the hairs when I reopen Blender (2.8)

If you make sure your UV map is clean enough to paint, then you can paint and then save the image to disk so it will keep the changed pixels. Using the image texture through an image texture node, you can specify the uv map to use so that it stays put in case you have multiple uv maps for other materials in your object.


One easy way is to use a displace modifier with a heightmap. Then use 'UV mapping.' If you use a field of shapes, and set the UV for the top of each cylinder to zero size, then it will be flat on top.

Example blend:


You were only displaying the first layer in your viewport. Make sure to highlight both layers when previewing.


Rigid Body stops at the upper surface of a hollow cube

Possibly your bin needs solid walls and floor (using the Solidify modifier and recalculate outside normals) rather than a cube with upper face removed.


Snap a bunch of keyframes to the cursor?

Within the Dope Sheet and the Graph Editor you can snap the selected keyframes using the snap menu - Key->snap or Shift-S and choose one of several options.

You can de-select all keyframes by pressing A then use box select B to draw a box around the desired keyframes.

The DopeSheet also has 'summary lines' for example the 'Cube' line. Selecting a keyframe in a summary line will select all related keyframes.

Also a common method to align things in blender is to apply a scale of zero.

In the Dope Sheet selecting the keyframes you want to align and pressing S then 0 will align them all to the current frame.

In the Graph Editor you will want to ensure you only affect the frame by scaling the desired points along the x axis (S-X-0). Here they will scale to a frame between the earliest and latest selected, then you probably want to move them to the frame you want (G-X)

The same scaling trick applies to aligning almost anything. Objects in object mode (you need to make sure you turn on manipulate centre points for object alignment), vertices in edit mode, curve points, armature bones, nodes...


Combining multiple textures with a white background

Here's an example with two images with a white background:

To keep the white and mix the two colors you can use a Color MixRGB node with Multiply as the transfer mode. Then plug that to only one Diffuse BSDF shader:

Using Multiply as the transfer mode (quoting from the wiki)

Returns a darker result than either pixel in most cases (except one of them >equals white=1.0). Completely white layers do not change the background at all. >Completely black layers give a black result. The "opposite" to Screen mode.

More info here


How can I connect the top loop to the down loop with faces

You should use Bridge edge loops command:

Select both loops:

2.Then click space and type bridge edge loops:

Click on it and its done:


Why texture size must be multiple of two?

Good question.

By ensuring the texture dimensions are a power of two, the graphics pipeline can take advantage of optimizations related to efficiencies in working with powers of two. For example, it can be (and absolutely was several years back before we had dedicated GPUs and extremely clever optimizing compilers) faster to divide and multiply by powers of two. Working in powers of two also simplified operations within the pipeline, such as computation and usage of mipmaps (a number that is a power of two will always divide evenly in half, which means you don't have to deal with scenarios where you must round your mipmap dimensions up or down)

This is a quote by stackexchange user "user1430", who answered the same question here.
Hope this helped :)


How can I make an object use it's animation action at a specific frame in Blender Python script?

I think Strips in the NLA are more suitable for your purpose than Actions.
Actions are containers for FCurves/keyframes.
Strips on the other hand are containers for Actions. Strips can be moved comfortably to the desired position on the timeline.
In the Action editor "Push down" you action as a new strip to the NLA editor. In the Nla editor you can drag the newly added strip anywhere on the timeline.
From here on you could toggle and move your strips on the timeline with Python.
Here's a quick sketch:
for track in bpy.context.active_object.animation_data.nla_tracks:
    for strip in track.strips:
        if strip.action == bpy.data.actions[0]:
            start_frame = 10
            strip.frame_start = start_frame
            strip.frame_end = (
                strip.action_frame_end - strip.action_frame_start + start_frame
            )

To add an action as a strip to the Nla, use:
start_frame = 10
strip = track.strips.new(bpy.data.actions[0].name, start_frame, bpy.data.actions[0])

Relevant API Docs:
https://docs.blender.org/api/current/bpy.types.NlaTrack.html?highlight=nlatrack#bpy.types.NlaTrack
https://docs.blender.org/api/current/bpy.types.NlaStrips.html#bpy.types.NlaStrips
https://docs.blender.org/api/current/bpy.types.NlaStrip.html#bpy.types.NlaStrip


If you look at the source code for the Anisotropic BSDF, you can see how the separate RoughnessU and RoughnessV parameters are computed from the input Roughness and Anisotropy settings.


calculate height, width and breadth of a object

Location and Dimension

In the image above is the Blender 3D View.  The information panel shows by pressing the letter [N] ... N.  The location and Dimension are shown.  The tooltip shows the Python expression for the dimension. Click on image to see original larger size.

This is not the whole story.  Know that object origins can be moved anywhere for your convenience or not.

Just a quick example of querying an text object. Example from another question.  Inspect and improve.  The blue objects are placed at x-axis rights side of characters.

Click on image to see larger version.

The console window of Blender.  Multiple queries.  After each Python statement I have edited text to add a character in the Blender 3D View edit mode.  Note the increasing X dimension for languages like English, French, Spanish (left to right and top to bottom) with left justified text.


How do I calibrate exposure to match a gray scale?

To create a Gray Chart is quite easy:
Give the object a diffuse shader and set the albedo to 0.18 (Meaning a reflectance of 18%)

If you render the image and left click on the UV/Image editor, you can sample where the scene referred values are, and how those are being transformed into display referred values by the color transforms set in the color management section. (For blender 2.8 right click on the image and the sampler window will appear)

The numbers that move at the bottom of the screen are (From left to right) pixel coordinates, Z depth value, then Scene Referred RGBA values, Then the RGB values that follow the CM (CM stands for color managed) are the Display Referred values, those of your final image.

Sampling will help you determine how the light is affecting your scene and how those values are being transformed on the final image.
So how are the scene referred values being transformed to display referred ones? It all depends on the settings on the color management.
For filmic blender, mid gray would be a scene referred value of 0.18, and it would get mapped to a value of 0.5 in display referred values. (sRGB tends to end up with display referred 0.5 at around 0.2 scene Referred)
If you are using Filmic Log encoding in as your view transform, you can also enable the False Colour Look. That will give you an interactive way to judge the "exposure" of your scene. Mid gray (in display referred values) will show as gray. Darker areas will be represented as blueish-purple and black, and bright areas as red, and eventually white once the values are too large.

Note that false colour should only be used with the filmic blender log encoding views. Using other view transforms will not result in an accurate representation.
For more details read the github page of blender render: https://github.com/sobotka/filmic-blender
So the same basic cube would look something like this in false colour:

Another example:
This scene (the cube is set with a reflectance of 18%):

Woulld look like this in false colour.

To understand how filmic blender works read:
Render with a wider dynamic range in cycles to produce photorealistic looking images


How to make things stay on animated character

You have to parent the glasses to the Head Bone. So then, when the animated character moves, the glasses move with the head.
So first, select the Glasses, then  Shift+RMBto select the armature. Then go into Pose mode of the armature and select only the head bone. After that, press Ctrl+P to parent the Object to Selected Bone


Use top-left corner as origin in Blender's camera

I've only one time used singular value decomposition with OpenCV

As I understand your question manipulating x0, y0 of the camera's intrinsic parameters (as interactivly possible in the 2nd page of your link) is similar to

import bpy

cam = bpy.data.cameras['Camera']
cam.shift_x += .5
cam.shift_y += .5

If this doesn't help you could try to offset the cameras position:

cam = bpy.data.objects['Camera']
cam.location.x = 0.0
cam.location.y = ...
cam.location.z = ...


Add more diffuse light, or lights from other angles, so that ripples don’t make such harsh shadows.


Smoke simulations, and – if "Disk Cache" is selected – also cloth and soft body simulations, will create a folder called blendcache_$file where $file is the name of your .blend file (fluid simulations will create cache_$file instead).

Those folders contain the results of baking the physics. Deleting them clears the bake; to bring your bake around (to another computer) it's necessary to keep those folders as sub-folders of your project.


How do I simulate "filling water" in Game Engine

Possible duplicate of this post. What you're trying to do is something not currently possible in vanilla Blender at runtime.

My advise is to fake it with different planes, particles, etc. but you have to learn Python to do this, and it will require a lot of work. Realtime simulations are demanding on your system, so even if you pull off full water simulation in Blender, 99% of everyone with a personal computer won't be able to run it.

So make a plane as your water surface, apply an animated texture to it, and animate the mesh itself. This way you'll at least have a water surface. For the inflow/outflow, make properties stating the water level. Animate this with two keyframes and let it cycle the values between 1 and 0 to make the water rise and fall. Animate some cylinders with the same process as the water surface so it looks like it's pouring out of something.

Remember, with any and every game, keep your polycount as low as you can. Running a water simulation at runtime will blow your polycount to the roof, and lag, or even crash on most systems.

Hope this helps.


Weight painting in rigging and particle systems combined

Solved it! There was one thing I forgot to try and that was adding bones for the eyes. Eventhough I did not plan to animate the eyes this probably is the only way to do it. Made 2 eye bones and 2 vertexgroups with the same name. The eyes move with the rig now and there is no hair on the eyes.


Edges not following the mesh in edit mode?

You have a subdivision surface modifier on your mesh. By default that modifier does not change the display of the original mesh while in edit mode. Its personal preference I like to see the original mesh most of the time, but coming from max I can see why you want the edges on the mesh.

Just head to the Properties window, then the Modifiers tab and look a the  Subdivision modifier (Subsurf modifier in versions prior to 2.8).  Then simply tick the button highlighted in red "Adjust edit cage to modifier result."


Why is my Subdivision Surface modifier acting up?

Tried to recreate your problem and i think you might have 1 extra loop cut there. Try to tab into edit mode, select all and then "remove doubles".


How can I achieve this texture result in Blender?

There are probably a lot of ways of doing that. You could just UV map the complex geometry. It doesn't seem like overlapping UVs would matter in this case. You could just select parts and project UVs from view how you need them. You can also use a multiple UV maps - maybe one for individual straps if they have some texture along the length, another for all of them(for the sides) based on camera views for the smooth bigger darker and lighter patterns.


How to get the directory of open blend file? (from Python)

Path Utilities module provides bpy.path.abspath("//") where the "//" prefix is a Blender specific identifier for the current blend file.

You can also do...

bpy.path.abspath("//my/file.txt")
bpy.path.abspath("//my\\file.txt") on Windows, with backslash escaped
bpy.path.abspath(r"//my\file.txt") on Windows, using python raw string
bpy.path.abspath("//../file.txt")  to go back a directory

This is used by all internal paths in blender, image, video, render, pointcache etc - paths. so blend files can reference paths relative to each file.

Worth noting that the path may be an empty string, so you may want to check bpy.data.is_saved first.


To use multiple directories on Windows, i edited the file 2.78\scripts\addon_utils.py and added my path in the function paths() beginning at line 48

def paths():
    # RELEASE SCRIPTS: official scripts distributed in Blender releases
    addon_paths = _bpy.utils.script_paths("addons")

    # CONTRIB SCRIPTS: good for testing but not official scripts yet
    # if folder addons_contrib/ exists, scripts in there will be loaded too
    addon_paths += _bpy.utils.script_paths("addons_contrib")

+   # ADDITIONAL SCRIPTS: for development
+   addon_paths += [r"C:\Users\plu\Documents\Blender\pyScripts\dev\addons"]
    return addon_paths

I also edited the file 2.78\scripts\startup\bl_ui\space_userpref.py and modified the draw method of the USERPREF_PT_addons panel beginning at line 1243, so that the addons from the folder will show up under the User Filter

def draw(self, context):
    import os
    import addon_utils

    layout = self.layout

    userpref = context.user_preferences
    used_ext = {ext.module for ext in userpref.addons}

    userpref_addons_folder = os.path.join(userpref.filepaths.script_directory, "addons")
    scripts_addons_folder = bpy.utils.user_resource('SCRIPTS', "addons")
+   scripts_dev_folder = r"C:\Users\plu\Documents\Blender\pyScripts\dev\addons"

+   scripts_user_folders = userpref_addons_folder, scripts_addons_folder, scripts_dev_folder

        # check if addon should be visible with current filters
        if ((filter == "All") or
            (filter == info["category"]) or
            (filter == "Enabled" and is_enabled) or
            (filter == "Disabled" and not is_enabled) or
-           (filter == "User" and (mod.__file__.startswith((userpref_addons_folder, scripts_addons_folder))))
+           (filter == "User" and (mod.__file__.startswith(scripts_user_folders)))
            ):

On Linux i create symbolic links in the addons folder. It is explained in this video


Yes! you can move the bones within Edit Mode. this should keep all of you weight settings as long as you've already parented the mesh to the armature.


Problems with rendering grass that is created by the strand renderer in cycles

I fixed it by myself. The problem was a setting in the 'Children' tab. It seems that the renderer in the viewport takes the number from 'Display' and  not from 'Render'.


How can I use the compositor on the result of the sequencer?

To use the rendered image sequence as input in the compositor, use the Image node. Select any file within the image sequence as input. Change the node's type from Single Image to Image Sequence, then set the sequence's length and first frame.


Save as EXR. EXR is the only linearized format available.


Laying eye shapes on a curved character head surface

1 Select your cylinder.
2 In properties select the chain link icon.
3 Select in [Add Object Constraint] the "Track to" option.
4 Target: choose the sphere. NOTE: The origin of both objects should be in their center for this to work.
5 Try different "To:" and "Up:" combinations until the flat side of the cylinder is aiming at the sphere.
6 To move the cylinder against the sphere use the translation manipulator, it normally says: "Global" next to it, change that to "Normal" and one of the manipulators arrows will align to the sphere to allow you to translate it till they connect.


What is the best tutorial or method to model a head?

You might want to check this dude Alimayo Arango out he has a lot of (Hyper-Detailed) character modeling tutorials (including other stuff!)

P.S His models/designs are Not AAA but i think they're enough to get you started.


The mug handle is not in the place I expected

This often happens when you extrude with CTRL + LMB🖱. It's better to model objects like that bevelling a curve and combining them with CTRL+J later. Bevelling a curve lets you shape the object any way you want changing the curve as long as it is in 2D mode. And the handle is not choppy then.


Does changing your Compute Device, change all computes of Blender?

Only rendering process can use GPU acceleration, specifically rendering with Cycles Render Engine alone; even switching to Blender internal ignores all benefits of GPU acceleration.

CUDA acceleration is not supported anywhere else in Blender. The only remaining parts, other than the OpenGL Viewport and UI Drawing, that use GPU acceleration (like Open Subdivide evaluation and Compositor OpenCL compute), are unaffected by the CUDA computing device settings, and use their own different settings in specific places.


Best Tile Size for Blender Internal Renderer and Cycles

I would say it depends a lot on the scene and the hardware.

BI:

Some tests rendering the default cube scene at 960x540 pixels:

Tile size:   32x32 Render time: 00:01.02

Tile size:   64x64 Render time: 00:00.89

Tile size:   128x128   Render time: 00:00.86

Tile size:   256x256   Render time: 00:00.87

Tile size:   512x512   Render time: 00:01.27

A more complex scene at the same resolution seems to go faster with larger tile sizes:

Tile size:   32x32 Render time: 01:53.57

Tile size:   64x64 Render time: 01:46.15

Tile size:   128x128   Render time: 01:45.26

Tile size:   256x256   Render time: 01:43.22

Tile size:   512x512   Render time: 01:43.09

Using the same scene at 960x540, I roughly timed the amount of time it took to render one tile. (This estimate is very rough because the time changes dramatically between different tiles, I just timed one tile):

Tile size:   120x67    Render time: 02:23.89 (approx. 12 seconds per tile)

Tile size:   64x64 Render time: 02:33.31 (approx. 6 seconds per tile)

Tile size:  300x300   Render time: 02:24.60 (approx. 30 seconds per tile)

Tile size:  200x200   Render time: 01:49.57 (approx. 10 seconds per tile)

Tile size:  100x100   Render time: 01:42.43 (approx. 14 seconds per tile) (fastest)

The fastest time here has the same settings as the slowest setup for cycles:

At 500x500:

Tile size:  128x128    Render time: 00:41.53 (fastest)

Tile size:  100x100   Render time: 00:41.92

At 512x512:

Tile size:  100x100   Render time: 00:43.67

Tile size:  128x128   Render time: 00:47.84

Cycles:

Using Mike Pan's famous BMW benchmark scene at 960x540 with 10 samples:

Tile size:  64x64 Render time: 01:51.03

Tile size:  100x100   Render time: 02:02.03

Tile size:  128x128   Render time: 01:49.64

Tile size:  200x200   Render time: 02:00.39

Some tests to see how much varying sizes and using powers of two affect render time:

At 500x500 px:

Tile size:   100x100   Render time: 00:46.86

Tile size:   128x128   Render time: 00:53.42

At 512x512 px:

Tile size:   128x128   Render time: 00:50.54

Tile size:   100x100   Render time: 00:49.46

Conclusions:

To find a general rule for deciding optimal tile sizes for any kind of scene, one needs a lot more testing data with long renders etc.
To really look at this in detail, I think some addon which would send tile settings and render times to a database would be necessary.
IMO, Setting the tile size to ~100x100 or ~200x200 and adjusting to fit evenly in the render dimensions is good enough.

However, from the tests I did above it does seem that maintaining a consistent tile size helps.
Power of two tile sizes seem to have no apparent effect.


Can i render particles from one object on 2 different render layers?

There are no settings to define which render layer a particle system is render on, the particles will all show on the same layer as the emitting object.

You could setup multiple objects, each with their own particle system and placed on a separate layer so you can render them separately. By using the same mesh, the particles can emit from the same positions and parenting the duplicate objects to the main object will let you move them all together. You can also disable selection of the duplicates so you can only select the parent object. The particle systems on each duplicate object would then have the render emitter disabled to prevent them from showing in the render, so you don't get z-fighting.


First question: it can be done in Blender in versions before 2.5, for example in now very old 2.49b. The file locations for download is here [1]. The mechanism you are looking for is called 'reactor particles'. It was unfortunately not re-implemented in 2.5+ series.

In Blender versions from 2.5 to 2.83 you can not do the effect of spawning particle with another particle easily. Particle system in Blender in it's current form is on it's end-of-life state, and there will be no updated to it, because it is planned to replace it by Particle Nodes. Example [2,3]. Some workaround for this poor situation is to introduce Animation Nodes [4] and find your way thorough them. This requires a lot of learning and is considered to be advanced stuff, so no point to explain it here. You really need a tutorial.

Second question: animation of flow can with direction can be done kind of easy using small custom object arrows and particle flow controllers like 'curve field' (curve guide) or 'keyed' particles [6]. This however requires also a tutorial, for example this (first from google): [5]

https://download.blender.org/release/Blender2.49b/
https://www.youtube.com/watch?v=A05UghlpVPs
https://www.youtube.com/watch?v=2tKpHuq9qEk
https://www.youtube.com/watch?v=8pvX2_ZH1l0
https://www.youtube.com/watch?v=PYHOV3bVIG0
https://docs.blender.org/manual/en/latest/physics/particles/emitter/physics/keyed.html


It is possible to Remesh text. You'll be converting to a Mesh anyway if you want to add particles, so what you might do is:

extrude the Text object ( in the properties panel )
Add Remesh Modifier with appropriate settings, usually you need a low threshold.

Convert to Mesh: Alt+C in Object Mode -> Mesh from Curve/Meta/Surf/Text , this will apply the Remesh Modifier too
and you'll get this:


Bridge Edge Loops is Blender's lofting tool, with a reasonable range of options.
One way to capture the curvature:

Rotate a duplicate of the top edge of your sole-rim upwards, towards the top profile of the shoe. If you have an actual front elevation of the shoe to work to, for the profile  edge, so much the better. (You could create a curve for that, convert to mesh, adjust the number of vertices to match the base edge. Loop Tools > Space is very handy for getting a fixed count of vertices evenly spread along a curved mesh-loop.)
Either use an existing top-surface, or extrude a temporary approximate one out, to give Bridge Edge Loops something to work to, and then use Bridge Edge Loops, with 'Blend surfaces' set. Adjust the number of 'Cuts', and 'Smoothness' to get as close as possible to your desired result.
Delete the temporary surface, and maybe Relax or Smooth some regions of vertices to improve the shape.

All this happens before detailing, and subdivision.


How to position an object in the middle of of two parts of another object

Select the top and bottom edge of the area you want to place the circle in the middle of. Press Shift+S and select "cursor to selected". As long as you have your Transform Pivot Point still set to "median", this will place the cursor in the center between the two selected edges.

Now when you add the circle, it will be placed at the point of the cursor (the middle).
From there, just rotate and scale the circle to your desire.


with the new particle system in blender 2.9 alpha this solves my problem


Why are UV mapped textures rendered as black color?

I found the answer!

After digging around and hitting random settings on just about any button and setting known to man, I discovered the Geometry Data under the Object Data (to the left of materials panel).

I hit Clear Custom Split Normals Data and the map showed up in the render! Now to figure out what the heck a custom split normal data is...


Add-on, how to format and use a custom path

It appears I was out of context.

Replacing:
context.scene.bbake.all_path

With:
bpy.context.scene.bbake.all_path

returned the string I was looking for.


You need light sources, or check in shadeless in the material tab, or increase the emission.


The solution is to make sure the object you want as your particle is facing straight up to the z axis. Then snap it or move it to the center of the grid in the cursor's world origin. That will draw everything in to the emitter to emit perfectly.


The diagonal line comes from the way you unwrapped the plane.

What you need to do is to push 7 to go to top view.
Then push 5 to go to orthographic view.
Lastly choose project from view bounds.

Before:

After:

EDIT: I misunderstood the question. The solution you are looking for is just to subdivide the plane. See this for why.


How can I convert the data from an image node into data for a mix node

Plug the output of the image node into the Mix Factor of the mix node:


Why don't you just use the handrail as a Start Cap model :p


Most of the information needed is already on this site.
Just to make your job a bit easier, here is how to make a cucumber slice.

Add a cylinder
Find a photo of a cucumber slice and a photo of a cucumber peel
Create and assign two materials (Add different materials to different parts of a mesh?)

Done.


You are on a Mac right?

I’m guessing it is post 2015 MacBook Pro?

Blender doesn’t support the proper display devices for MacBook Pros. You’ll need my GitHub version.

TL;DR: What you are seeing in Blender is wrong, and Preview is interpreting it as correct. I’d also encourage you to not render with the sRGB OETF as it is subject to colour skew with saturated colours.

PS: If this confuses you, I’ve recently covered this very subject over at the Hitchhiker’s Guide to Digital Colour. I’d recommend starting at the first question if this guess of an answer proved correct. https://hg2dc.com/. Feel free to ask any questions.


Spot light looks fine in the viewport, but when I render the result is different

Never mind, I forgot to delete some area lights ♂


Animation: Creating random pulses (not noise) on a F-Curve

You can add some different noise modifiers, and restrict their frame range.


How can I change a sphere's radius with a Python script?

There are many ways to do this, the least complicated approach is probably this:

import bpy

properties = [
   [[-2, 0, 0], 0.2],
   [[-1, 0, 0], 0.3],
   [[+0, 0, 0], 0.4],
   [[+1, 0, 0], 0.5],
   [[+2, 0, 0], 0.6]
]

# [co]ordinate, and [r]adius
for co, r in properties:
    bpy.ops.mesh.primitive_uv_sphere_add(segments=34, size=r, location=co)

See the documentation for UV Sphere

Depending on scene complexity other approaches will make more sense.


What is the function of "removing doubles UV"

This is a very useful function when making textures for game assets.

When modeling game assets you usually get a lot of similar faces that could use the same texture space, so you want to align them on the same spot. But to save even more space, it's a good idea to use the "pack islands" function.

If you haven't merged the UV's with the "remove doubles UV" function, they will get separated again and moved to different parts of the map.


I can only zoom to the center not to where i point

In Blender 2.9, go to Edit > Preferences > Navigation, then check "Zoom to mouse position" for the zoom, and check "Orbit Around Selection" for orbiting.


Edit mode with vertex selected, N key to toggle open the Properties panel > Item tab > Transform, Vertex


Convert Houdini Matrix To Blender Matrix?

Thanks for the replies. I also got replies on BlenderArtists as well. I finally found a solution that works for me so I thought i'd post it here for others to use.

Run this code in the Blender default scene and the camera will jump from one location to another. The new location is defined by the string that holds the Houdini matrix.

import bpy, math
from mathutils import Vector,Matrix

def applyTransform(sMatrix, passedOb):
    if passedOb != None:
        tmp = eval(sMatrix)
        mtx = Matrix(tmp)
        passedOb.location = [mtx[3][0],-mtx[3][1],mtx[3][2]]        # Flip Z and Y axis.
        mtx.transpose()                                             # From BL Stack user.
        rot_x_neg90 = Matrix.Rotation(math.pi/2.0, 4, 'X')          # From Kastoria.
        passedOb.matrix_world = rot_x_neg90 * mtx                   # From Kastoria.

# Matrix string from Houdini object.
s = "[[0.900496, 3.27826e-007, -0.434865, 0], [-0.117881, 0.962558, -0.244102, 0], [0.418583, 0.271075, 0.866779, 0], [5.32776, 2.57303, 7.33473, 1]]"
ob = bpy.data.objects.get("Camera")
applyTransform(s,ob)


Is there any way to re-render without having to rebuild the entire scene again?

You could hide the objects that are taking up unnecessary performance, to preview only the ones you want or what will give you a good preview. You can also render only a small part of the image. Here's a tutorial https://www.youtube.com/watch?v=94UsZw6mTaE


Regarding vertices.

There is a menu option ... Hide Vertices.
This Hides the current selection.

Vertex groups give a reusable name to vertices. In case you need to hide vertices repeatedly.


It's only obvious if you know how blender works. What is happening is the mesh data is copied into a bmesh structure when you go into edit mode, this bmesh data is copied back when leaving edit mode. The changes you make to the underlying mesh data while the mesh is in edit mode are overwritten by this process and won't affect the mesh that you see in edit mode.

If you move your set use_seam loop to above the set edit mode you will get the result that you expect.


Calculate Faces from Point Cloud with Python

OK my search for this answer wasn't so straight forward. I knew how to solve this with MeshLab, but I couldn't get another python functions to work so...

I ended up just writing a script that ran MeshLab. This helped: https://stackoverflow.com/questions/54143202/using-meshlab-function-with-python

The only thing to note is that it appears that calculating normals via the script wont work. Other than that follow the instructions for running a script.


It can't emit particles with animation node

Blender's particle system integrator resets the simulation every time an unexpected change in the object's transformation happen. Try moving the object mid-simulation and you will find that the particles resets. As far as I know, to work around this, you need to bake the animation into key-frames so that Blender's know about the transformation in advance.


If you've set up your object materials in the Blender Internal render engine mode, and then switch to Cycles, the materials are not compatible.

You'll have to create new Cycles materials that match your BI (Blender Internal) versions, and apply them to the object instead of the BI versions.


Delete linked node from out-/inputs index

The case in your picture can be done like
in_soc = your_principled_node.inputs['Base Color']  # example
if in_soc.links:
    from_node = in_soc.links[0].from_node
    your_material.node_tree.nodes.remove(from_node)


You can use the Project Paint settings to get around this - by default, Occlude, Cull and Normal are all on, as well as a 2 pixel bleed. You can uncheck these like I show in the picture, and then your paint will paint through the mesh all the way like a blade - and if you want to only do some of it, you can use the Face Selection masking in the header window, right next to the drawtype icon.


You can use video or image sequence exactly the same way like texture.

In Node editor:
"Shift + A" -> "Texture" -> "Image sequence" (select all images "image.000" - "image.xxx").

Or you can choose "Texture" and open video file exactly like image.

Now you can setup video texture offset and start frame.
Start frame: when video start playing (timeline frames)
Offset: set first frame where video start play (video texture frames)

Example:
You need start playing video texture on frame 1250 of your animation and you want to jump on 10th second in your video texture. (remove first 10 second from video texture)

Set Start frame to 1250
Set offset to 240 (for 24FPS: 24 x 10 second)

There are also "Frames" - you can use it for stop play video texture. Frames = video texture frames, not your animation frames on timeline.

Second option is using Material ID for creating mask and add video to object using this mask in Video Sequence Editor or in Compositor.

Personally I thing the 1st option is easiest way how to do it, just play with setup to achieve what you need. :-)


How to fix weird edges when doing knife project?

So basically. Learn something new every day, even if it's super simple. Conecting Ngon edges to some lines solved the weird bits. I used Knife tool and made every odd shape into little squares.


Can blender be used to analysis the acoustics of a 3D designed room or hall?

E.A.R seems to be pretty much what you looking for
although it hasn't been updated for quite long
https://blenderartists.org/forum/showthread.php?252708-E-A-R-Evaluation-of-Acoustics-using-Ray-tracing
http://www.explauralisation.org/


In the 'Image Editor' window, where the white render appears, you have selected to view the alpha channel of the image. Because the image has no transparency is displays as solid white. You need to switch back to 'Color' mode to view the colours of the image:


Quad faces along the curve or grease pencil

Yes. Since at least Blender version 2.65, the grease pencil has included a "convert" button, one of the options of which was to convert the grease pencil work to a bezier curve. Selecting the bezier curve, and applying the command ALT-C permits the conversion of the bezier curve to a mesh object. From there it's just a matter of applying standard modeling techniques to convert the edges to quad faces. The following image exemplifying this technique was made by adding a bezier curve to a scene in top orthographic view, selecting all vertices, witching to front orthographic view, and extruding along the z axis.

[

At some point, changes to the grease pencil made the process easier, since version 2.78 gives as one of the options of the convert button in the grease pencil tool panel, direct conversion from the grease pencil to a "polygon curve". However, I have no direct experience with trying to make that conversion.


Either you forgot to set the color space of your image texture node to non-color data, either you obtained a normal map in DirectX format instead of OpenGL format, in which case you need to invert the Y channel of your normal map:


how to animate atoms finding and binding to eachother

I think you should look at using force fields physics,
Here is a short tutorial that might get you on the right track:
https://youtu.be/ebgHGmjf5Nc


blender renders wrong portions of video strips

That's most likely a problem due to a broken Video file. The internally used ffmpeg libraries don't work too well with some video formats and are not able to always provide the frames without artifacts and in the right order one by one. I bet your Screencast software didn't do a good job in encoding your footage.

So try to repair your footage. And then instead of using RecordMyDesktop to capture your screen you should use Open Broadcaster Software recording to file, not LiveStream. It should provide you with non-problematic footage that you can use with Blender without problems.


Unfortunately your AMD R9 280 card doesn't fulfill the requirements for GPU rendering in Blender 2.8x. You would either need a

Nvidia graphics card with CUDA compute capability 3.0 or higher
AMD graphics card from GCN second generation or later

The AMD R9 280 has the GCN first generation architecture.

  CUDA

  CUDA requires graphics cards with compute capability 3.0 and higher. To make sure your GPU is supported, see the list of Nvidia graphics cards with the compute capabilities and supported graphics cards. CUDA GPU rendering is supported on Windows, macOS, and Linux.

  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.

Please note that the requirements for GPU rendering are higher than the minimum requirements for running Blender.

  These requirements are for basic Blender operation, rendering using the graphics card requires slightly different requirements.


Face masking for texture paint in UV / Image Editor

Not really at the moment.

Masks are not supported yet in the image editor though it is a feature that we will surely be implementing in the future.


Motion Tracking works in viewport, but not in Render

It is impossible to help with motion tracking without looking at the shot, and the nodes used on the compositor.
A few comments:
An error of .8 pixels is still too high, you should aim for an error of .3 or lower.
Use the graph and dopesheet to see if any trakers have a high error value.
The most common error in tracking happens if you try to use the default solver on a shot where the camera is not moving, or where the camera is stationary and just tilting and panning. Those shots can only be solves as "tripod". And will not give you any 3d information.
If you haven't already please read the detailed post on this site on motion tracking:
How can I get better results when doing camera motion tracking?


This might take considerable more work for more complex shapes but one way would be to use the Shrinkwrap modifier to snap the outline of the shape to your mesh.

Next, join both shapes and delete the parts of the sphere that your outline contains, now fill in back the rest of the shape.

As I said, this method is not perfect and would require some careful editing to make sure the mesh keeps its curved appearance but for simple outlines/shapes it should work fine.

General tips when doing this are to keep your outline clean and preferably as lines as the Shrinkwrap modifier tends to distort faces depending on the surface it is snapping to.

Another way would be to use the Boolean modifier and cut out the shape.

Add the modifier to the object you want to cut and select the object (an extruded Blender logo in this case) and set the operation to Difference with the logo as the target, delete the outside piece of the logo and you should have a nice cut out shape on the sphere.

Once Smooth Shaded this will be very blocky but running a Tris to Quads operation with AltJ and applying an Edge Split modifier should make it look better.

If you need bevelled edges, the boolean modifier leaves very sharp cuts so you should be able to select the jumbled ones and merge and dissolve vertices as needed until you get a clean edge ring without affecting the curvature of your shape much.


While resizing an object by script: 'tuple' object does not support item assignment

Works fine here, maybe that's an error from a previous state in your script. It does not come from this snippet.

import bpy

def create_cube(name, cornerPos, size):
    # Set cursor position for the current brick
    bpy.context.scene.cursor_location = cornerPos

    # Add a cube primitive
    bpy.ops.mesh.primitive_cube_add()

    # Get its reference via the active object, and rename
    theBrick = bpy.context.active_object
    theBrick.name = name

    # Set size
    bpy.ops.transform.resize(value=size)
    bpy.ops.object.transform_apply(scale=True)

    # Return the object
    return theBrick

create_cube("woop", (0,1,2), (1, 2, 1))

The error message

  TypeError: 'tuple' object does not support item assignment

is something you might get if you have the following code

>>> some_tuple = (0, 1, 2)
>>> some_tuple[2] = 4  #  <-- you can't do this in tuples
Traceback (most recent call last):
  File "<blender_console>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment

tuples are immutable, if you want to modify an individual element's value then you use a list.

>>> some_list = [0, 1, 2]
>>> some_list[2] = 4
>>> some_list
[0, 1, 4]


Brick texture - controlling the randomness

OK well as usual, an hour after you ask you find the solution...

Turns out I was misunderstanding how the brick texture works - it doesn't generate a discrete set of colors, it draws a new random color for each brick. So each color is random across the entire color spectrum, and I can classify them using a ColorRamp after all.


Manually make it look like an object is going through the floor (of a real life photograph)

Update for posterity: An archive of this answer can be found at https://bvisness.me/2017/04/25/blender-masking-layers.html.

Blender has a feature called Masking Layers, which nicely accomplish exactly what you're trying to do. Put your content cube on one layer and your masking plane on another, then set the Masking Layer for the plane's layer. I got my result to look like this:

Here's how to accomplish that effect:

1. Set up your layers

Start by turning on transparent film. This makes your Cycles render layers use transparency instead of a background color. Go to the Render panel in the Properties window, scroll down to Film, and check Transparent.

Put your cube (or other content) on one layer and your masking plane on another. I had my cube on layer  and my plane on layer

Make sure that both your cube and your plane are visible, then go over to the Render Layers tab and set the mask layer to the layer with your plane.

To overlay the render on your image, you can use a compositing setup like this:

Give it a render, and you'll get something like this:

This technically answers your question, but it looks really bad, so I'm gonna keep going.

2. Add shadows and AO

You can use your masking plane to capture shadows and AO as well. First add another render layer for just your masking plane. Go down into the "Passes" tab and make sure that Shadows and AO are checked.

Then, use a composite setup like this to mix the shadows and apply them to the original image:

This will result in a render like this:

Just one more step, if you want the lighting to be more accurate:

3. Make the floor material match the picture

You can improve the lighting accuracy if you make the floor material match the picture. This will change the color of the light bounces, even though the plane itself is not actually visible.

Create a material with a node setup like this and assign it to the floor:

This material will use the coordinates of the window to apply the picture to the floor. This means that there will be no distortion of the texture when it is rendered. This change will result in a subtly improved render:

This technique works for other objects too. Just replace the cube with whatever object you actually want in your scene.

Anyway, I hope that helps. Let me know if you want me to clarify anything.


Your graphics card has a CUDA compute capability of 2.1, however GPU rendering in Blender 2.8 requires a compute capability of 3.0. That is why your graphics card isn't listed.


How to fill element with color in texture painting?

If you have selected your element or island with L in edit mode (selecting linked mesh), or if you have selected a vertex group in edit mode prior to entering Texture Paint mode, then you can certainly choose the Fill tool and drop paint into just that area provided you have enabled Face Selection Masking in the icon  in the 3d view header. In the Tool Options panel, you can choose how much bleed area you get past that selection, and you can choose to use or not use Cavity masking there as well if you are wanting some degree of edge wear.

For painting a pattern in a brush only in that area, the best mapping method here would be '3D' so that the pattern could be connected later to another part of the painting, respecting the mesh normals.


How to make each letter a single object?

With converted Text to Mesh go to Edit Mode, Select All (A) then hit P and choose 'By loose parts'.


Transluscent leaf using principled shader

Final result:

I will show you two methods, first one (Translucent) is recommended because it's a lot faster approach and also with less geometry. For both of them you will need Mix Shader with Transparent BSDF and Alpha from Image Texture as a Factor.

Example above is rendered with only 32 samples. Beneath both meshes there is a light source to show the effect.

Translucent:

Simple mix between Principled BSDF and Translucent BSDF, both with Image Texture as a Color. Factor between them will allow you to control how much light will go trough mesh.

Subsurface:

For this method to work you will need to add some thickness to your mesh. I've added Solidify Modifier with pretty low value:

And node setup:

Choose color of Subsurface to be close to the Image Texture and set Subsurface strength.


Textured alpha not showing in the game engine?

Try switching to GLSL shading in 3D view > Properties region (N) > Shading:

Then it works as expected:


This PLY is too dark! How to improve it?

I think that there is not a Blender-related issue: the vertex colors are the ones the file provide.

Here's what they look like in Meshlab:

And in Blender:

put apart the different viewport shading by seeing the true solid colours in cycles preview or textured mode in blender render, and you'll see no difference:

You can tweak the vertex colors with nodes as liked:

Note that vertex colors are changed only in the viewport, for rendering purpose, not in the vertex color layer. If you want to store a new, brighter, vertex layer you should:

bake cycles tweaked vertex color to an image texture
convert the texture to a new vertex color layer


Drag and drop multiple files in the VSE?

Not by dragging directly form the OS (at least in Windows).

But you can import several video files simultaneously by selecting them on the file browser window.

Press ShiftA to add a video track.

On the file browser window use Shift to select more than one file manually

A to select all.

B to drag-select.

All the selected files will be imported sequencially on a single time line:


Cull Particle Simulation when not visible to the camera

I think this video is the best answer to your question Vertex Weight Proximity

By adding arrayed plane to your camera as a child you can point which part of particles (or anything that is using vertex groups) are to show up.


Attempting to layer two materials on the same parts of a mesh

You can use the following steps :

create two UV maps in the vertex panel

create a material for all faces of the hull like this :

A diffuse BSDF (for the hull details) and a Emission BSDF (for the windows ligght) are added together (using a Mix BSDF should be better). The strength of the emission BSDF is increased to 10. The diffuse BSDF is connected with the hull details image which is connected to the UV map of the hull. The Emission BSDF is connected with the windows light image which is connected to the UV map of the window.

Unwrap the hull on the hull image like this (note that windows are painted with black)

Unwrap the windows on a white part of the windows light image. Then unwrap all other faces on a black part (they are all stacked in the orange square at the bottom)

The size of the windows light can be very small (256px x 256px) because it contains only white and black surfaces.

Here is a final render :

If you add an object near the window, you will see that it will be lighted by the window light.


Animated textures are supported for Eevee as of the latest builds. The change was added during the week 11-15 February.


Is scaling to absolute zero a bad way to hide an element?

In my opinion, you are fine to use zero for a scaling factor for objects - those scaled meshes will simply be reduced down to a point, but with no actual loss of geometry; increasing the scale factor again will restore your mesh and while scaled down to a point will not be visible in your render.

However, for scaling faces, you will lose geometry by scaling down to zero in Edit mode - since all vertices will exist at the exact same point so there is nothing to 'scale back up'. Note though, that in this situation, even scaling down to a very small scale (but not zero) may introduce rounding issues with the vertices in your mesh when you scale back up again. The exception to this is if you are scaling the faces using a modifier (such as an Armature or Deform modifier) since the underlying geometry is not actually affected and so can be restored without distortion.


Blender Game Engine Python Flipper Animation

The flipper mode belongs to the action armature. This makes the actuator play the animation forward on activation and backward on deactivation.

The actuator uses the internal animation system to play the action in response the the current status (activated or deactivated) and the animation status (playing, reaching end).

The internal animation system can only act according to the animation status.

The simplest solution is to activate/deactivate the action actuator in flipper mode.

E.g.:

import bge
import math

controller = bge.logic.getCurrentController()
owner = controller.owner

keyboard = bge.logic.keyboard

xyz = owner.localOrientation.to_euler()
xyz[2] = math.radians(180)

if bge.logic.KX_INPUT_ACTIVE == keyboard.events[bge.events.RIGHTARROWKEY]:
    owner.applyMovement((0, 0.08, 0), True)
    owner.worldOrientation = (0, 0, 0)
    controller.activate("turn right")
    controller.deactivate("turn left")
    controller.deactivate("jump")

if bge.logic.KX_INPUT_ACTIVE == keyboard.events[bge.events.LEFTARROWKEY]:
    owner.applyMovement((0, 0.08, 0), True)
    owner.localOrientation = xyz.to_matrix()
    controller.activate("turn left")
    controller.deactivate("turn right")
    controller.deactivate("jump")

if bge.logic.KX_INPUT_ACTIVE == keyboard.events[bge.events.SPACEKEY]:
    owner.applyMovement = ((0, 0, 0.08), True)
    controller.activate("jump")
    controller.deactivate("turn right")
    controller.deactivate("turn left")


Built-in Tools

In the Properties window's > Camera > Display settings you can enable the visibility for limits. It will show you a line and a crosshair for the focus in the 3d viewport:

If you are using cycles you can see the depth of field in rendered view. To set focus precisely is to use an empty and have that empty be the focus object. Moving the empty will move the focus distance:

There is one point where things are in focus, objects closer or further away will be less sharp (or blurrier). Depth of field is defined roughly as the range (distance) in  which "things are acceptably in focus", before they are considered blurry.

What is acceptably in focus is determined by the size of the circles of confusion. Watch this video for decent explanation of circles of confusion: https://www.youtube.com/watch?v=Pdq65lEYFOM

The depth of field depends on 3 things:

Lens size - Shorter lenses will have more depth of field. Selective focus is easier to achieve with longer lenses.
F-stop - Smaller values for f-stop (a wider aperture) will make the circles of confusion larger before and after the focus distance, resulting in less depth of field. In blender you can set the f-stop to values that could not be achieved in real life, where it would be impossible to get a lens with an f-stop of 0.01. a larger value for the f-stop will result in larger depth of field.
Focus distance - The closer the objects are to the lens, the less depth of field a lens will have, if you look at images taken with macro lenses you will see that is focus is critical.

Another variable to consider is the sensor size. Using a small sensor requires the use of shorter lenses, making selective focus harder to achieve. Larger sensors will require longer lenses, making it easier to get a narrower depth of field.

There are no tools to visualize the depth of field in blender as far as I know (other than through the camera view). But there are plenty of depth of field charts and calculators online, and a multitude of apps for that.

Depth of Field Utilities

This Add-on allows to visualize the Depth of Field limits (near limit & far limit) directly in the viewport:

Once the Add-on is enabled, select the camera, open up the Properties region of any 3d View (N), scroll all the way down to the bottom and enable the visualization. From there you can fine tune all relevant properties of the selected camera as well as using the 3d Cursor to set the focus distance:

Notice that you can disable the instructions to hit Esc in the Add-on Preferences if needed.


How to increase render preview bounces? (Cycles in viewport)

I found a cause of the problem. Simplify is active and limiting the number of Ambient Occlusion bouces in the viewport. I just match the values to get a similar render.


Adding several deform points in one circular object (belt)

I might try attaching the buttons to a flat, heavily subdivided belt, and then selecting all the buttons, and scaling down with proportional edit turned on.


Find out if Mesh Operator (bpy.ops.mesh...) was cancelled or not via python

This looks at the TRANSFORM_OT_translate.value Vector as shown in the 'INFO' reports.  If the operator was cancelled it returns (0, 0, 0) else has a length.

import bpy

wm = bpy.context.window_manager

print("TESTing Extrude Op")
for op in wm.operators:
    if op.bl_idname == 'MESH_OT_extrude_region_move':  #name == 'Extrude Region and Move'
        print(op.name, "Found")
        v = op.macros['TRANSFORM_OT_translate'].properties.value
        if v.length:
            print("operator used")
        else:
            print("operator canceled")


There appears to be an issue with that node in conjunction with the Bump node. One solution that appears to work is using the Wireframe node in conjunction with a Normal Map node:

These nodes render a result like this:

Notice that these values can be inverted as well:

One word of warning thanks to @WChagrin:

  I would say that that's almost certainly undefined behavior. The colored pixels in the normal map are supposed to represent unit vectors in tangent space. When the wireframe node outputs a value of 0, that's coerced into the vector <0, 0, 0>, which is not only non-unit, but non-normalizable. That is, trying to normalize it would require division by zero. Relying on this behavior is probably a Bad Idea™.


How create Action strip for more objects in NLA

You only need to animate one object, then copy it to the others. To copy, select all object you want to use the same animation data, the one to copy from as the last selected. Then execute Object > Make Links... (shortcut Ctrl-L), and choose Animation Data.

Note that if Location property is keyframed in the action, all objects using the action will jump to the same location. To offset from original location, use Delta Location instead. The same goes with Rotation and Scale properties.

EDIT: If you want to merge animation data of several objects, I don't think that's possible. At most, you can manipulate all of them in the Dope Sheet, where animation data for all animated objects are displayed. I use this a lot when I have to synchronize the animation of several objects (three, in illustration below) at once:


How can I render these edges more realistic?

You can edit the edge sharpness by increasing the 'Mean Crease'


Overlapping faces while extruding corners

You should try to avoid overlapping geometry, like faces that occupy the same space creating z-fighting and other problems.

One of the many ways to go about this is to use loop cuts, and use those that define the places where the intersections should take place, and more importantly to create new vertices for such intersections.

Select one of the newly created edges, extrude to the point where the new vertex is (Enable snap to vertex for precise placement). Select the matching edge on the other wall and pres F to create a new face.

At the end of all of this do "remove doubles" to get rid of extra vertices


How to do weight paint on one side, even with mirror modifier

The vertex weights checkbox on the mirror modifier will make it mirror weights to 'mirror' groups if they exist. E.g. weights in Group.L will be mirrored to Group.R if Group.R exists, otherwise those mirrored weights will be assigned to Group.L

It always surprises me how few people seem aware of this behaviour.


Needing help creating an fluorescent glass shader

Add Emission shader to the Volume input of Material Output node:

Further you can also add in Volumetric Absorption and Scatter nodes to simulate a real medium inside, not just light originating from the volume.


The best way to do this is to make a  linked duplicate of your original object (ALT+D) and then rotate it 180 degrees on the z axis. They will technically be separate objects, unlike  a modifier, but editing one will change the other accordingly.


You've set the background image to the viewing position Left, but to show the background image you should be in Orthographic mode not Perspective. Press 5 on keypad to set Orthographic


Add a reroute beween your principled BSDF and your texture
Select both the bsdf and the reroute
Go to Add > Group > Make Group (CTRL + G )
Link the group input to your color and delete the reroute

Go back to the shader with TAB or the arrow in the top right
Now you can plug your image in the group
Create another shader, delete the principled, add your group with Add > Group > NodeGroup and plug your other card image
Example with procedural textures but it can be used with image textures :

Note the "2" on the right of the name of the node group. That means that it currently has 2 users. If you want to make a hard copy and edit it independently, click on the number and the name should change. The resulting node group will not be shared with the other ones.

If you want to tweak the roughness for example, select the node group and tap TAB to edit it.


How to control a short "animation" with a single bone?

Blend file
I took your blend, made a copy of the landing gear and rig and deleted the animation.
I then added Transformation Bone constraints to four of your bones; arm1, arm1.001, pad, and pad_backflip. Notice the different values of the Min and Max for the Source Z axis on the Transformation constraints. That is how I timed the different parts to happen at different times. Your Control_bone drives all of the Transformation constraints.


Shader turns black when connected to node group

This is because you are plugging a Shader output (green) into a color input (yellow). See What is the meaning of the color of the node sockets in the node editor?

Instead you should add a shader input (green) to the "Logo Overlay" group. Doing this is a little complicated, as you currently can't directly set the socket type without some python. However, it is possible:

Enter the node group (↹ Tab)
Plug the placeholder output of the Group Input node (hollow) into any input socket of the desired type. In this case, green for shader:

Optionally rename the new input in the properties panel (N).

Once this is done, your setup should work.

I don't recommend putting the material output node inside a node group, as this could lead to confusion down the road depending on how the group is used. Instead you might want to plug the mix shader into a Group Output node, and plug the entire group node into the material output in the main node tree.


How can I cut a circular hole into this curvy shape?

Actually it looks like the "crown" is a distinct part:

So I would create 2 different objects, and for the main part I would do it this way:

Create your basic shape from a subdivided cube:

Use the knife tool to cut (K to activate, Z to cut through)

Press V to separate, delete the useless part.

Mirror the shape, merge some vertices with alt M to keep a clean topology:

Give your object a Subdivision Surface modifier, extrude the hole, add some edge loops to sharp the edges:

Alternative topology (no triangle):

You could also use a Shrinkwrap modifier to get a different topology:


Check the "Size" option in the explode modifier. This will make the particle size affect the size of the exploded fragments.


I cannot create a mesh (the dimensions are all set to 0 whenever i do try and create one)

I'm not sure but i might try to add new Objects (Create Tab -> Cylinder)

(Actually, I would use a torus )

and join the whole thing later on. (Ctrl+j)

Problems:

the object may need three different textures, one for one engine, one for the other, and one for the rest. (i had such issues, i don't know if that happens)


The basic idea for generating outline effect comes from Cycles Wireframe Shader from agus at BlendSwap.

General Step:

Create a UV layer (which is used for generating "procedural" wires), then unwrap the mesh by the "Reset" method in U menu.
Create another UV layer (used for baking), which should contain the expected UV.
Create an Image Texture node and keep it disconnected to any socket. then bake Diffuse color onto the target image.

NOTE: Before baking, make sure the target UV layer is activated.

More guidelines about baking.

EDIT:

There should be more than one way to do so. Another way is to use Texture Paint mode to paint it manually: Select all Faces then hit I twice to Inset individual faces, then invert selection for masking in paint mode. It does work, but you can hardly get smooth result in this way.

A third way is using Export UV Layout. Though you've mentioned that "Export UV Layout" should not be an option here, I still recommend you to try Paul Gonet's solution again. Just plus one more tip —— use Dilate/Erode node to get proper outline width. Then you can use File Output node to output the outlined texture while rendering again. Finally you can reuse it back to the model.


where is the blender rock generator addon?

You can download the add-on from here: use the "Download > Direct Download" button that will create a .zip file.

You will be able to install the add-on from File > User Preferences > Add-ons, using "Install from File" and selecting the zip file. You don't have to unzip it!

I haven't extensively tested it, but the basic features seem to work on Blender 2.79b on Ubuntu (even if the file is much older).

More in this answer by Thom Blair III. I don't know who maintains the Dropbox link above.


Edit mode required first for Texture Paint to work

Try mixing the colors in the shader editor first, then from the 3D Viewport switch to Texture Paint mode (Ctrl+Tab, 9).
In Texture Paint mode from the Properties Panel (N), select the Tool tab.
Select the base material, then you can select which texture you would like to paint on from here.


How to prevent a newly create window to change its content when switching between workspaces?

The only solution I found is to create an extra camera and lock it to the view. Then you'll have to make the camera active in each workspace to be able to switch between the workspaces, preserving the angle of view. A bit annoying workflow, but it helps to solve the problem


How can you change the curve resolution of hair particles?

There are three different settings which control this:

3D view > Particle edit mode > Tool shelf > Options > Draw. This setting affects the curve resolution in the 3D view only while in particle edit mode.
Properties > Particle settings > Render > Steps This setting controls the number of steps in the final render.
Properties > Particle settings > Display > Color This setting controls the number of steps in the viewport, outside of particle edit mode.

The Segments setting at the top of the particle settings controls the number of control vertices there are, however doesn't affect the number of interpolation steps. Think of this like scaling and image up with Nearest interpolation; you end up with more pixels, but the result is not smoothed.


How important is modeling to scale for animators?

Size is extremely important to animators. The size of the model determines how the animation will look. A building-sized ant-man will have different motion than a tiny-sized ant-man.

But in 3D the scale is relative, you can pretend 1 unit is 1.5m or 0.5foot or anything if everything adheres to it in the project and you don't care about anything outside of project and you communicate what the size is to the animator. But why to complicate life, just make 1 unit = 1m and be it self-explanatory. It's similar reason as to why name everything nicely in the scene - it will work the same as with bad naming, but the other person using that file will have so much easier time having everything self-explanatory named.

Having the scale to real-world units starts being really relevant when simulations come into play. Simulation engines do take size of objects into account. You cannot no longer just make it proportional and pretend the size is anything you want. And animators can do simulation stuff too.


The render result is correct but when in the viewer node the render is going off screen

Without having your .blend and image files at hand, I can't tell for sure what is happening.

However, usually a "Scale" node (found under "Distort"), set to "Render Size" and applied just after the Image input, should guarantee that RenderLayers and external images have matching sizes. (Note: if the image is smaller than the render layers, it will be stretched, losing sharpness in the process)

I don't know, however, why they don't match already if – as you say – you already changed the resolutions in both the image and Blender. I can just suggest to check again.


How to make render toggle visible by default in 2.8?

Open a new file and set up things the way you like and then save your start up file.
It's located under the file menu.

File > Defaults > Save Start Up File