Concept

I first want to talk a little bit about the Armature/Animation concept as far as I understand it.

Bone

A bone is an element of the armature. You can see it as a structural element. You can view and modify the bones when you switch the armature to edit mode tab (in Blender).

You can't and you do not want to modify a bone within the game.

Channel

You are talking about a channel. A channel is a set of transformations of a single bone. Bone transformations can be translation, rotation and scale in any combination (material channels have different transformations). These transformations can change over time. I guess that is why it is called "channel" it is a flow. The transformation at a specific time is a "pose" of a bone. The pose of an armature contains the poses of all channels. You can see the channels when switching the armature to pose mode ctrl+tab (in Blender).

In Blender channels will be applied to bones of the same name. This is a loose coupling between these different entities. The great benefit is that you can apply an armature pose to a different armature. Only bones with the same name will receive the according bone pose from the channel.

Action

You can fix a bone pose by setting up a keyframe I. This keyframe will belong to an action. The action can contain several channels with multiple keyframes. The poses without keyframe will be calculated on the fly (within Blender and within the BGE).

The loose coupling between channels and bones allows to easily apply an action to another armature as long as the bones names match.

As you want to change the channel via custom code we do not need to look at actions any further.

Modifying Channels via custom code

Within the BGE you can access the current channels of an armature.

import bge

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

channel = armature.channels[0] # first channel

The channel has several attributes that can be changed. You are looking for a rotation.

Be aware there several different types of rotations. You set up the type in Blender or via BGE custom code.

I strongly suggest you always check the rotation mode rather than assuming it is a certain one. Mostlikely there will be no error when the mode is not what you expect but the resulting behavior will not be correct. So it is important to ensure it is what you need.

if channel.rotation_mode == bge.logic.ROT_MODE_XYZ:
    xyz_rotation = channel.rotation_euler

A rotation consists of several components dependent on the rotation mode. Directly modifying a component channel.rotation_euler.z = 10.0 will not result in a change of the rotation. You need to assign the rotation to make it effective:

    xyz_rotation.z = 10.0
    channel.rotation_euler = xyz_rotation

Btw. this belongs to nearly all operations that deal with Vectors. I'm not really sure but I guess the BGE does not notify when you change a single component. But it notifies when you exchange the container (by assigning a value to the attribute).

Remarks

I haven't used custom code to modify channels in the BGE only for investigation to your questions.

I noticed that changing the channel alone does not have immediate effect. Activating an armature actuator applied the changes from code. There might be other ways.


Is there a python binding for Undo/Redo?

Yes, absolutely.

bpy.ops.ed.undo()
bpy.ops.ed.redo()

More operators of that kind here: https://docs.blender.org/api/2.79/bpy.ops.ed.html?highlight=undo#bpy.ops.ed.undo_redo


Rotate the camera while driving along the path

You can make it follow a path with a Follow Path constraint, and the camera itself can have its own keyframes in the Dopesheet, in your case along its Z axis.


How do you return a hidden panel in the properties

Start by creating (splitting) a new area, then set its type to outliner.

Click and drag the hashed corner overlapping the area you want to shrink in order to make way for the new area.
Click the drop down on the far left of the Header of the newly created area
Select Outliner
(optional)  RMB anywhere on the header and select Header > Flip to Top.

You can read more about the interface system in the manual.


How can I keep hard edges with this shape?

The easiest way would be to delete top faces, extrude rim and close the cup in different way, but if you want to keep quads, use bevel edge, by selecting outer edge and pressing CTRL+B and moving mouse to set bevel size.Her are both ways:


Creating an Unwrapping Animation (NOT texturing)

I'm not quite sure what you are trying to achieve, but I created this blend file that turns a 2D fan into a 3D cone... https://www.dropbox.com/s/zjddbv90rfj48n8/Cone2Dto3D.blend?dl=0 . Just press Alt+A to run the animation.

OK, since it was requested, here's the instructions....

0) To get started, Num Pad 7 for top view and Shift+C to centre cursor at origin.

1) Add a mesh circle with 72 sides, triangle fan fill, 1.1536m radius. [Any strange dimensions given here are due to the maths required to make a cone that ends up as 1m tall. I did do the maths but deleted it].

2) R, Z, 2.5, Enter, to rotate circle about Z by 2.5 degrees.

3) Tab into edit mode and delete 71 of the faces, leaving just the one at the 12 o'clock position.

4) Add an Empty ('Empty1') at the origin (i.e. the sharp point of the triangle).

5) Select just the triangle and add an array modifier, Count=36. Turn off Relative Offset and choose just Object Offset, specifying Empty1 as the Object Offset.

6) Rotate Empty1 5 degrees about Z to cause a fanned array of triangles in a semi-circle.

7) Add another Empty ('Empty2') at the point of the triangle (I used the Single Arrow style to make things clearer). You should get an arrow pointing up the +ve Z axis.

8) Select Empty2, then shift-select the triangle, hit Tab to edit triangle, shift select the vertex at the point.

9) Press Ctrl+H, Hook to Selected Object. (Moving Empty2 can now drag the triangles up and down into a point... but leave it where it is for now at Z=0).

10) With the triangle still in edit mode, select the other two vertices only (Ctrl+I), Shift+S, Cursor To Selected. The cursor should now be between the two vertices at the outside of the triangle.

11) Tab out of edit mode and then A to deselect the triangles.

12) Add another Empty ('Empty3'), single arrow style, then press R, X, 90, Enter, so it points back towards the point of the triangle (along the Y axis).

13) With Empty3 selected, shift-select the triangle, Tab, Ctrl+H, Hook To Selected Object. [Moving Empty3 can now squash the triangle towards the centre... but leave it where it is for now at Y = 1.1536m.]

14) Tab out of edit mode and A to deselect all.

++ Now the animation ++

15) Set start frame to 1, end frame to anything you like.

16) At Frame 1, select Empty2 (the arrow pointing upwards) and set a key frame for Loc Z (i.e. Z=0).

17) Go to last frame (Shift+Right arrow). Move Empty2 up to Z=1 and set a keyframe.

18) IMPORTANT! Go into the graph editor and set interpolation (T) to Linear.

19) Go back to Frame 1 (Shift+Left arrow), select Empty1 and set a keyframe for Rot Z (i.e. Rot Z = 5 degrees).

20) Go to last frame. Rotate Empty2 another 5 degrees about Z and set a keyframe (i.e. Rot Z = 10 degrees). [You should have a droopy propellor / palm leaf thing now].

21) IMPORTANT! Go into the graph editor and set interpolation (T) to Linear.

22) Go back to Frame 1, select Empty3 and set a keyframe for Loc Y (i.e. Y = 1.1536)

23) Go to last frame. In top view, select Empty3 and set its Y location to Y = 0.57625. The triangles should join exactly to make a cone. If not, move Empty3 manually along Y until they do.

24) When the triangles meet exactly, set a keyframe for Empty3's Y location.

25) IMPORTANT! Go into the graph editor, select Empty3's graph and open the Properties panel (P). Set Interpolation to Sinusoidal, and set Easing to Ease Out.

26) Alt+A to run animation.


Looks like the problem was that I had 'UV local' view selected, in the UV view options. Not sure what that means yet, but fixed the issue for me.


Blender 2.8 scene collection not update when adding new objects

Tldr : Press TAB to toggle between edit mode and object mode.

Blender has two separate modes for editing objects (object mode) and editing geometry (edit mode).

Right now you are adding more geometry to the same object, in edit mode. In edit mode, you can add the same default primitives (cylinder, sphere, cube...) as in object mode, but this will not create a new object, only add to the existing object's geometry.

If you want to create new actual objects, you need to toggle the mode into object mode with TAB or click the foldout menu in the top left of your 3D view.

Incidentally, if you select two or more objects in object mode, then go into edit mode with TAB, you will be able to edit all of the objects' geometry at once (Since Blender 2.80).


glass shader not working with normal map in cycles

I SOLVED IT !!! I did another object and again I ran into the same problem. But this time the mesh looked fine from above but completely black from below. I switched from object space to tangent space and after a few hours I decided to play around with the normal map strength and it seems that glass shader doesn´t like normal map values greater than 0.4 and After 0.46 the mesh starts looking completely black.

this values are for my particular project.


Limit on MixRGB nodes per material? Or How to render out an image sequence

Okay, so the original challenge was to create a material that would change every frame, so that I would end up with 33 images that would have a different art piece on the wall.
First, I tried using a mixRGB shader animated to switch between images. But, I got stymied by a memory problem. Blender would only see the first 8 images before it seemed to lose its mind.
Then, on a recommendation from @no-can-do , I switched the image texture node from single to image sequence.
This seemed to work until I rendered, then it would lose the images again.
I upgraded from 2.82a to 2.83, and rendered again. And, it worked!
Image sequence is set up with the number of frames (number of images in the directory I was linking to), start frame of 1 with 0 offset. I also clicked the Auto Refresh on.
Here's my set up:


Change the Piovt point to "Median Point"


Keyframe not animating bone from initial position?

You need to set an initial keyframe for any animated data, including armature bones, in the first frame. The pelvis left bone is set to that position at frame 40, but because there's no keyframe before it, its position is interpolated all the way to the starting frame.


How do I get rid of artifacts on boolean text?

You have shaded smooth your object but the topology is bad (ngons and stretched triangles), therefore these artefacts. But it depends on what you want to do at the end, if you don't care about having a perfect topology and you want a quick fix in order to have a correct appearance, use the Auto Smooth option in the Properties panel > Object Data > Normals. It will smooth all the angles below the angle you'll set and keep the other ones sharp, therefore it will remove all these artefacts:


After selecting your armature, go into edit mode and select the bone you want to join to your master bone (in your case, the lowest is your master bone). While in edit mode, go to:

Properties >> Bone >> Relations

and under "Parent", select the master bone and tick the "Connected" box. If you haven't named your bones, you might have to try all of them but luckily you've only got 3.


Complete black in material preview shading tab

It seems, that the material has no shader input. Blender used the default "no shader" and this is simply black.


how to extrude neighboring vertices without creating a face in between?

use CtrlV to get to vertices menu, then extrude vertices will extrude only the vertices.


Viewing my objects in the default 3d (iso) view

This is the default view Blender starts at. There is nothing special about it, so there naturally is not hotkey. However, you can restore this view by assuming its position by rotating the interface.
I am unsure from your question whether or not you are actually able to rotate the viewport. If you cannot, simply hold down the middle mouse button on your mouse and move around. If you do not have a middle mouse button/ are using a touchpad, then you can go to user preferences, and enable "Emulate three button mouse". This allows you to rotate the viewport by holding the left mouse button, and pressing the Alt key on your keyboard.
If you, however, can rotate the interface and I am mistaken, you can, immediately after opening Blender, press Ctrl+Alt+0 on your keyboard to align the camera to that default view. Make sure you have not already moved the interface around.
As I said previously, there is no "default" key to this view, so you must align your camera to the view if you want to get it again. If you don't want to do this, you can try to achieve the same view by rotating your viewport.
I hope this helps.


Problem using Voronoi texture as Cycles displacement (2.8)

Displacement is usually done along faces normals. This is the role of the 'displacement vector' to help to do that.

If you use any vector like a color as displacement in the output node, the displacement will operate directly in the directions given by this vector and this will not consider faces orientations. This is the case in the image in your question.

So simply insert a 'displacement vector' (which can be found in the 'vector' category) between your displacement calculation and the output.

Here is a view with on left an exaggerated offset when 'displacement' is not used. And on the right, the same with a displacement vector.

(Note that the 'screen' node is not useful here I think).

Blender file for 2.8, Cycles experimental using adaptive subdivision:


Bake to a prop, find the ramge.  map to [0, 1]

In the code in

https://blender.stackexchange.com/a/39241/15543

I show how to get the minimum and maximum value of an fcurve.  The range of the fcurve. (It is generally always  the case that the minimum is 0 for baked fcurves). The range is  A = max - min .   This can also be done pretty much by eye, picking the maximum and minimum points and noting the values in graph editor..

For sound drivers, (which is very much on back-burner, there is an aubio version for 2.8 coming which bakes up to 10x quicker in my preliminary tests) I used these for control points on an fcurve envelope modifier to map the range to [0, 1]  With the unit range, the curve can be amplified with a generator modifier, or a via a variable with A * fcurve.evaluate()  the inverse is A * (1 - fcurve.evaluate(frame))

The last image of https://blender.stackexchange.com/a/39241/15543 shows a baked sound and its inverse as the amplitude is changed.

Here is a section of that image showing the envelope modifier.

action frame range 1 to 44, fcurve has max 0.3 something, mapped to [0, 1] with envelope

Here is some code from sound drivers to add an envelope modifier. The min and max of the fcurve is the default min and max of the modifer. The envelope control points are added at each end of fcurve and map range to range [0, 1].

        action # the action
        fcurve # an fcurve from that action
        _min # calculated min of fcurve
        _max # calculated max of fcurve

        mods = [m for m in fcurve.modifiers if m.type == 'ENVELOPE']
        # remove mods (shouldn't be any)
        for m in mods:
            fcurve.modifiers.remove(m)
        # add a new one
        m = fcurve.modifiers.new(type='ENVELOPE')
        m.default_min = _min
        m.default_max = _max
        # add a control point at start end
        for f in action.frame_range:
            cp = m.control_points.add(f)
            cp.min = 0
            cp.max = 1

Recommend baking to some custom property to avoid having to bake sound for each animated property. Bake once drive with that.

How to bake multiple audio sounds to f curve?

Unbaked

If you have unbaked the fcurve you can simply select all the kfps of fcurve in graph editor and S Y-1 to invert using scale.

PS This is my little part of blender as a patch needed to be written to expose envelope modifier control points to the python API.


Object appears bright even when there is no light

This is because the dragon's texture is influencing the Emit property of the material. If you disable it in Properties > Textures > Influence (with the dragon selected), it works as expected:


Compositing with Shadow Pass Mask

It seems compositing and shadow pass mask is the way to go with this in Cycles.

Once everything is set the render output would be the result of compositing so there is nothing complex to repeat at all. It is possible to hide the extra texture inside the shader with very low emission values that would not add to the 'exposed' visible range of the colors so no extra render layer would be needed and the extra emission shader does't influence the render times in any meaningful way. We could use emission strength of 0.0001 and in compositing just multiply the emission pass by 10000 and since the values are 32 bit floats, there would be no loss in color detail.

You would need to add an Emission shader to all of your materials that would contain the shadow texture for them(even if you wanted the same texture it would need to be there so it does not render black). You also need to have all the passes needed to reconstruct the image enabled. If you needed an emission pass for regular use, some extra masking may be required to separate the actual values from the ones 10000 times weaker, but it could be something like this:

Just to clarify - the emission pass in compositing is multiplied with a simple Color Mix node in Multiply mode entering 10000 as R,G and B values:


Blender 2.81 adds support for the Voxel Remesh operator, which can efficiently get rid of intersecting geometry such as meshes generated by tightly turning or self-intersecting beveled curves, for example this one:

The step by step process goes like this:

Ensure that the endpoints are capped - you can manually add faces later but since you are using a profile curve anyway, it's easy to add caps right here:

Convert the curve to mesh: Object -> Convert to -> Mesh From Curve/Surf/Meta/Text.

Press F3 (operator search) -> type "Voxel Remesh"

The result should now be something like this. Note that there are visible "welds" because the voxel resolution is not too big.

To adjust the parameters for the voxels, select the mesh, enter sculpt mode,

Then on the properties window adjust the settings for the remesh operation.


In the Shader editor create a new blank image in the low poly anvil's material and set its panel active (select it and its white outline must be appear). Select the high poly anvil then the low poly (so the hp must be orange, the lp must be yellow) and click on bake in the render properties panel. You have to increase the ray distance a little before the baking (probably mine wasn't the optimal).


How do you stop Blender from looking for an image texture?

if the textuures are really not used, you can find them in the outliner > orphan data

they are "orphan" because they have no object or anything that uses them (quite an amazing naming scheme hahaha)
Then you will find a "purge" button,
this will "purge" or remove all the orphans (sounds wrong I know)

Then, all of the unused materials will be removed from the blend.file
or you can do this to, go to file > clean up > and remove all unused data blocks


To join meshes ideally they should have the same scale (set to 1:1:1 with Ctrl+A -> Apply Scale) and there should be no modifiers active (under the Wrench symbol on the right). Maybe one of these is causing issues?


Extrude faces of an icosphere from a python script

bmesh.ops.extrude_discrete_faces takes a list of faces and extrudes them, leaving them in the original place with new joining geometry. If we take the ['faces'] part of the data returned by extrude_discrete_faces we have a list of faces that have been extruded, these are the 'original' faces only, not the extra joining faces.

For each of these extruded faces we take the face normal and multiply it by the distance you wish to move the face and use that in bmesh.ops.translate to position them where you want.

import bpy
import bmesh

# sample set for cube
extrude_values = [0.1,0.2,0.3,0.4,0.5,0.6]

obj = bpy.context.active_object
bm = bmesh.new()
bm.from_mesh(obj.data,face_normals=True)

extrude_faces = bmesh.ops.extrude_discrete_faces(bm, faces=bm.faces)['faces']

for f_idx in range(len(extrude_faces)):
    dr = extrude_faces[f_idx].normal * extrude_values[f_idx]
    bmesh.ops.translate(bm, verts=extrude_faces[f_idx].verts, vec=dr)

bm.to_mesh(obj.data)
bm.free()
obj.data.update()


Animate the Viewport Visibility of an Object within the Timeline?

Make your Object visible at frame 30:

You can keyframe the Viewport Visibility of an Object from within the Outliner:

In the Timeline select Frame 1
Then open the Outliner
Set your Object to Hidden
While the mouse hovers over the eye icon in the outliner, press I to keyframe the visibility.
Move on to frame 30
Click on the Eye icon again to make the object visible
Then press I again to keyframe the visibility change.

Note: If you want to achieve the same for your render, then please check the answer in here: How can I animate the Restrict Visibility property of an object?


Yeah, the stretch-to constraint doesn't let you pick.

There are two solutions here.  The easier is to change your mesh so that its local Y axis is what you want to change.  Select the object and snap the cursor to its location.  Open it up in edit mode and change the pivot point to the cursor.  Select all and 'r' 'x' '-90' to rotate it.  Now what was your local Z axis is your local Y axis.

The other way to do this is to use a driver to control the scale, and constraints only to "clean up" afterwards.  Drive the scale of the object using the distance between self and target object.  Then you can add a damped track constraint in any axis you want, and possibly a preserve volume constraint to alter the scale in other axes.


You need to add the Volume Scatter node to be able to colour tint the smoke.


lost a background image after an animation render

Did you save your hand-painted image texture externally? When you first paint a texture in Blender, it's only saved in cache. If you change frames, close/reopen the project, or move stuff around, you risk losing that work.


Is there any Property in the bpy.props which can take multiple lines of text?

Blender doesn't have a multi-line text/string property at the moment that could be edited in UI panels like other bpy.props.
There are some workarounds to render multiline texts from text objects in panels, but I think you want to render a string as a multiline text into a Text object.
You could still use the StringProperty to let the user enter text in a single line and let him mark new lines with \n. The captured string could then be placed in a Text object like so:
some_text = 'line one\nline two\nline three'
bpy.data.texts[0].from_string(some_text)

Also see related questions:

UI: Text box with multiple lines
Change size of StringProperty Text Input
Is there a way to display a multi-lines message in panel / popup?

Btw there's a more or less corresponding feature request on Right-Click Select: https://blender.community/c/rightclickselect/S6fbbc/
I'd appreciate the addition of such a multiline text property among the bpy.props.


Is there a way to restart a modified addon?

You can go to the Main menu > Blender > System > Reload Scripts. As the name suggests, the operator reloads all addons and scripts, running addons, unregister and register functions.

Another way is hitting F3 and typing "Reload Scripts" in the Operator Search menu and execute the operator. In versions pre Blender 2.8x you can just hit F8 in order to reload.


How to make a edge of an object curved (I don't think I'm saying that right but please help!)

You could need both subsurf and/or bevel, depending on what you need.

Here's an example, starting from a box extruded and shaped to a similar starting object:

the edge trick is shown on the right wireframe: adding edges near subsurfed rounded corners, you get somewhat sharp edges if you need them, but leaving subsurf for the rest of the mesh...

Hth


How can i model a propeller like the one in the image?

Apparently there are many different shaped airplane propellers. After some Google searching I found this Creative Commons CC0 1.0 Universal Public Domain Dedication reference image of a simple two blade propeller.

   Add the reference image as a background image in Front View.
   Add a default UV Sphere Shift + A > UV Sphere. Tab into Edit Mode, then press Z to go into      wireframe display.
   Press S and scale the Sphere to fit the propellers cone.
   Then delete the bottom half of the Sphere.
Tab into Object Mode, and rotate the Sphere 90’ around the x axis by pressing A to select all then press R + X+ 90.

Tab back into Edit Mode and select the middle vertex.
Press 7 to go into Top View.
Press O and Enable Proportional Editing > Connected and choose a Falloff type. I choose Linear.
Press Press G + Press Y to grab it on only the y axis. Control the number of vertices affected using       the mouse wheel.
Disable Proportional Editing by pressing O.

Delete one half of the Sphere.
Add a Mirror Modifier and check the box next to Clipping.
Add a Subsurf Modifier and set the view to 2.
Tab into Object Mode and set the shading to Smooth. *The Smooth Shading option is only          available in Object Mode. (Pressing  T toggles the Tools panel on/off).

Tab back into Edit Mode. Press 3 to go into Side View.
Press Z to enter wireframe view and also click the “Eye” icon in the Subsurf Modifier to disable it temporarily.

Select the following four faces.
Press 1 to go into Front View.
Press E +  X to Extrude along the x axis only. Left Mouse Click to confirm extrusion.
Press  S +  X to flatten the end vertices on the x axis.

Ctrl +  R to add several Loop Cuts. I added 10. (Change the number of Loop Cuts with the mouse wheel) Left Click to confirm then Right Click to set in place.
Align the vertices on the outer edge of the mesh with the edges in the reference image. I used  Shift +  Y to avoid moving them in them on the y axis.
Add one more Edge Loop close to the cone and then move the bottom vertices up.

Tab into Object Mode.
Apply the Mirror Modifier.
Tab into Edit Mode.
Press  Z” to go back into Solid View and click the “Eye” icon in the Subsurf Modifier to turn it     back on.
Enable Proportional Editing.
Select the vertices at the end of the right propeller blade.
Press  R +  X to limit the rotation to the x axis. Type in the number of degrees you want it to rotate. I used 60’.
Repeat for the other blade in the opposite direction.


Viewport only shows part of the scaled cube

In the Viewport hit "N" to show the Properties panel.

Then, under "View", change the clipping "End" value to fit your cube.

(Note: 1km is the default value.)


All you have to do is animate the camera too. You're already animating the helicopter to displace the camera. Now animate the camera to give it the desired details, as if the person inside was moving its head.

There might be a script or something to do it automatically, but seems to me like it would be actually more complicated.


Shading for my hands geometry is different to rest of model

Okay the normals for my geometry were flipped, you can flip them again by selecting all the faces, then press W, then select Flip Normals.


How to use all the audio and video strips in the VSE as a video texture?

No the VSE is simply a post production tool at the end of the 3D chain. You'll have to render the sequence out then import that as a video texture. You cannot define a scene output for use in other 3D elements. However you can use Compositor or VSE in another scene's compositors or VSE editors.


Select the edge loop in center and add an edge crease with
Ctrl + E and set the crease to 1
Bevel the edge with  Ctrl + B
Inset the new faces with I followed by
Ctrl to use depth (intrude)
Add Subdivision Surface Modifier and shade smooth


What is the best export format from AutoCAD -> Blender?

I have always found FBX to be the most reliable way to export from Autodesk products for use in Blender. It tends to keep the correct dimensions, UVs, and Blender can estimate the materials quite well (albeit with some junk nodes thrown in for maximum compatibility).

That being said, it seems Autodesk has been removing FBX exporting from AutoCAD, so I don't know if that will be the best option for you if are using or plan to use AutoCAD 2019. I have heard from an interview with Ton Roosendaal that Autodesk has been removing FBX because it has become too accessible to 3rd parties, and so they can't make as much money leaving it available in their software. A shame, if true, but there could be many other reasons we aren't privy to.


Use a curve for each segment between timestamped camera points

For the follow path constraint, with fixed position, offset, 0 is start point and offset 1 is the other end point of curve.  If instead of using an n point bezier curve,  we use n - 1  "segment"  beziers, we can use this feature simply.

The curve of points [p0, p1, p2] becomes two curves [p0, p1] and [p1, p2].  At the frame specified for camera to be at p1 can either be offset 1 of first segment, 0 of next  Note segments don't have to be 2 point beziers, just require last point to match first point of next.

A follow path constraint is added for each segment.
To make the object use the particular segment we set the influence  to 1 to use this constraint 0 otherwise. (or set hide inversely). We want the influence of the constraint to be 1 when the current frame is between the end point frames (from your data), Otherwise it is set to 0 and has no effect.

The offset can be calculated using (current_frame - p0.frame) / (p1.frame - p0.frame)

A test case setup using drivers

To each bezier curve segment we add two  custom propeties, "frame_start" and "frame_end" ( curve_object["frame_start"] = 44 ) indicating the frames at which to be at end points. (I've used integers here, floats would be much better in hindsight)

via UI, adjust the min / max to suit

Now we set up a couple of drivers.  The use_self option of the driver is handy here. The constraint itself is self, the path is self.target, from which we can get the frame range for this curve.

setup in UI, make sure use_self is checked. Might have to click "Update Dependencies".

The driver expressions used are in_segment(self, frame) for influence, (could also drive is_expanded and hide)  and segment_offset(self, frame) for offset. The argument frame is known to the driver name space and is context.scene.frame_current.  Run script below to define methods and register to the driver namespace

import bpy

def in_segment(self, frame):
    segment = self.target
    if not segment:
        print("No target")
        return False
    frame_start = segment.get("frame_start", 0)
    frame_end = segment.get("frame_end", 0)
    return frame_start <= frame < frame_end

def segment_offset(self, frame):
    segment = self.target
    if not segment:
        print("No target")
        return 0
    frame_start = segment.get("frame_start", 0)
    frame_end = segment.get("frame_end", 0)
    duration = frame_end - frame_start
    if not duration:
        return 0
    return (frame - frame_start) / duration

bpy.app.driver_namespace["in_segment"] = in_segment
bpy.app.driver_namespace["segment_offset"] = segment_offset

Now with this setup can add a bezier curve, set the custom properties, then add a follow path constraint, set as curve target,  and the constrained object will follow that curve for the defined frame duration.

_Cube switching between four bezier circles. The constraints expand is also driven by the influence. Each circle has a 10 frame duration, hence on the smaller circle cube apppears slower. _


How to achieve animated handwriting with variable thickness?

You can control the thickness of a curve's bevel by changing the radius of a particular segment:

To get something like this:

Examlple file:

Be aware that the tools to create and manipulate curves in blender are not as responsive and sofisticated as other programs out there, so to create complex curves like this, it might be easier to work in Inkscape, Illustrator or other vector graphics program and export the file in SGV format and import it into blender.


Just move the vertices back where you want them in Edit mode. Looks like they’ve been moved only in the X direction so should be simple enough to G (grab), X (in X axis only), drag them back. There aren’t many so shouldn’t take long to put them back.
It’s difficult to give more precise instructions without knowing about what it is you did to mess them up.


How to generate an animated tie dye-like gradient as a texture?

You could try to use the Wave Texture node, then play with its Distortion value and with parameters of the Mapping node:


3D Manipulator only selects a handful of times

After looking through the 3d-manipulator questions this helped me find the solution.

It turns out I somehow locked my objects to another object. I don't know how I did it but after clearing all the objects from having an object they were locked to it fixed the problem.

My view field looks like this now:


The issue is most likely that you removed the composite node accidentally in the composite node tree.

Select the composite node tree button (highlighted left).
At this point, we should take a step back, and make sure that what I think is happening, is happening.
There are two signs that I'm wrong:

Use Nodes isn't enabled
There is a composite node

If both of those aren't true, then continue.
Now there are two ways you could solve this.
#1
You could disable Use Nodes. When this is disabled, anything in the compositing node tree is ignored.
#2
Or you could add in a composite node, and attach it to the Render Layers node.
ShiftA output -> composite.

And then attaching the render layers node to it.


Excluding part of the mesh from mirror modifier

ok, I found a good workflow to do it, I applied the mirror modifier then I activate/deactivate the X Mirror checkbox in the mesh options tab whenever I want to work on the symmetric/non symmetric vertices respectively.

note: this only works for the meshes symmetric along x axis (but still useful :))


How to create color bleeding for material?

Data Transfer a vertex color

A procedural approch would be to use vertex colors. Paint the icing black, duplicate the sprinkles and join them and paint them white. Duplicate the icing and join it with the joined sprinkles. In edit mode of this merged geometry, shrink the icing ⎇ AltS. Then (to the actual icing) add a subdivision modifier, add a Data Transfer modifier and finally another subdivision modifier using cycles experimental adaptive subdivision. Transfer the vertex colors from the icing_sprinkles_helper object to the icing. Use the vertex colors in the material to apply it to the color.

This procedural approach is complex, computing intense (many polygons) and produces mediocre results, so let's go with the destructive easy method.

Bake bleed to a texture

Temporarily change the lighting:

make springles emissive
make the icing diffuse
remove all other light source (by moving them to other layers or disabling them)

Unwrap the icing and create a new image. Add this image as an image texture node in the icing's material and select it (it should be active). We are going to bake on it.
Bake the direct diffuse component of the icing.

We will now have an emissive map, this is not accurately bleeding, due to the random rotation of the sprinkles.Duh, whatever.

Connect this texture to the fac of a color mix node, mixing icing color with sprinkle_bleed color.

You can also bake multicolored sprinkles, just separate the Value (used for the factor) and the Hue and Saturation (used for the color).

Examples are highly exaggerated. Use a more moderate falloff with the RGBCurves node.


Is the Principled shader a combo of all shaders?

No. The Principled BSDF shader is a combination of several other shaders, but it is not a replacement for them. From the Blender Manual:

  It is based on the Disney principled model also known as the “PBR” shader, making it compatible with other software such as Pixar’s Renderman® and Unreal Engine®. Image textures painted or baked from software like Substance Painter® may be directly linked to the corresponding parameters in this shader

None of the current nodes are obsolete or deprecated. There are, however, two main advantages to this shader:

First, as you pointed out, it is a combination of the other shaders, using physically based formulae. This means that we can plug is colors and values without having to worry whether or not what we are creating looks realistic. (This means that it has built-in Fresnel).

This second advantage is that it uses Disney's standardized shading model, making it so that results with Cycles should match up with results in Renderman, Unreal and Substance Painter. This can save a lot of time, especially for someone who switches between software.

It isn't a replacement for any nodes, though, since it might be faster or simpler to just use more basic nodes.

Of the 16 other shading nodes (not including Add, Mix, and Principled), these 5 can be replicated with Principled BSDF:

Anisotropic BSDF
Diffuse BSDF
Glass BSDF (called Transmission)
Glossy BSDF (called Specular)
Subsurface Scattering1

Principled BSDF does not cover any Volumetric shaders, transparencies other than Glass, or more specialized effects like Velvet2, Toon, Ambient Occlusion, or Hair.

1 While this does simulate Subsurface Scattering, it does not use the same algorithms as the Cycles Subsurface Scattering node, see this answer.

2 The sheen property is meant to simulate cloth, and so is similar to the Velvet shader. The Velvet shader has more options though (and I assume slightly different equations), so I wouldn't consider it an exact duplicate.


The curve contains too many unnecessary points. Additional curvatures will bend the object where you don't want.

For better control in this case, I suggest to separate planks from poles, making them as two individual objects. Then use one simplified curve (or two curves) to control each of them.


Here's a variation on Jens Clar's answer.  You can connect the output of the Emission shader node to the Volume input of the Material Output node.  Here's an example using the Translucent BSDF node connected to the Surface input of the Material Output node:

Here's the node setup:


Rigging mesh with vertex weights: different weights have the same influence

Even with a weight of 0.001, the vertice will be part of the group and the bone will displace it 100%. I think 0.001 must be the lowest value you can enter. But if you create a second bone, parent it, then give a weight of 0.002 to some of the vertices (vs 0.001 for the same vertices in the previous vertex group), the influence of this second bone on these vertices will be twice the influence of the first bone.


Solidify Modifier: how can I remove the inner mesh in a complex artifacts?

Not sure if I understand correctly but I think you may be misunderstanding what the Solidify modifier does.

It creates thickness on an object by duplication it's faces and offsetting the  by a specified distance along its normals. This makes it two sided, and creates a new set of faces virtually "duplicating" your object.

That being said you may use it for what you want by activating the options Fill Rim and Only Rim, that way only the distorted "cage" will be created, and no duplicates will be found.

Edit

See an example of an open area bellow where additional faces are created.

Have you tried the Smooth modifier instead? It wont create additional faces, and will have a similar offset effect, though it may cause some distortion in tighter corners.

Edit 2

Apparently the user's problem was with selecting linked geometry in edit mode.
You could apply the Solidify modifier with the Fill Rim option unchecked, and then enter edit mode and either hover one of the unwanted vertex and press L or select one of the unwanted vertex and press Ctrl + L to Select Linked


Curve modifier does not work when you merge another curve to the original curve

The Curve Modifier only reads the first spline segment of the curve object.

Either join all segments into one continuous spline, or use separate objects for each stretch of track.

There are also a myriad of issues with your scene, one of each is unnapplied scale on the mesh. See my answer for common issues with the Curve Modifier

Besides that, the root of the problem seems to be extraneous geometry in your curves. Both of them seem to have loose vertex that unexpectedly make them multi spline curves causing unexpected behavior.

Erasing loose geometry and applying scales should solve your issues. TO easily erase all loose geometry, select one vertex of your main spline, then press Ctrl + L to select all linked vertex.

Afterwards press Ctrl + I to invert selection, effectively selecting all vertex that don't belong to the main spline, then you can erase them.


I don't know why your hand controller is rotated, because your metarig doesn't produce that. You might have done something we don't know to get that. Fixing it manually might take some time.

However, since you're using Rigify and that your metarig seem to be correct, it will be quite simple: regenerate your rig from your metarig and it will be fixed.

For that, select your metarig object. Then in the object data tab, head over to the Rigify Buttons panel, usually located at the very bottom. You will just need to change the target object in your meshes's Armature Deform modifiers for them to be deformed by your new rig. The skinning should remain intact.
If you want to generate a new rig, simply hit the Generate Rig button.
If you want to override your already existing rig, hit the Advanced Options button first, set it up like the following and then hit the Generate Rig button:

No need for modifiers retargeting this time.


Changing the resolution of the image merely renders it bigger. In the image below, I've change it to 500%, and that would blow up both the X and Y dimensions five fold, i.e. making it 6400x3600 pixels rather than the 1280x720 entered in the X and Y boxes.

From your screenshot, I'm guessing that you're using Cycles, and grain/noise in Cycles usually means too few samples. Try increasing the Render value under samples. What you need exactly depends highly on your lighting and materials among other things, so I can't say specificly what you'll need.

Changing the Clamp values usually reduces noise as well, by clamping out very high intensities.

You can read more about it here.


Sorting wrong when sorting Vertices and Faces

partly solved!!  (see comments below)

OK then....

Just updated Blender from 2.71 to 2.72.... everything works as it should now, weird!!  The vertices and faces are sorted properly.

Had 2.71 on PC and laptop, still got 2.71 on PC and it doesn't sort the vertices properly, now that I've updated laptop to 2.72 that works fine!!

Some weird bug that they've fixed?  Either way, I'm good now.

Thank you stacker and G.Rassovsky for your responses.


As you are performing the parenting, look at the top of your window, towards the middle. I am willing to bet that you will see an error message of some kind when you do so. The proper solution to your problem almost definitely depends upon what that message says. If it happens to be the trusty Bone Weight error, good luck... I have been trying to solve that particular issue through DAYS of research, but perhaps you will have better luck.


[Blender 2.80]  I made an object similar to yours and discovered that applying a bevel to the edges "did" distort the walls of the cylinder when "all" surrounding edges were selected at once.  So I tried to apply the bevel to the edges in stages.

First I beveled the 2 bottom edges (.05 amount), then just the sides and lastly the top edges and it worked... with just one division bevel.  I tried it again with a second window (same staged process).  This time I applied 2 bevel divisions and found that the corners were not well done.  But, with some manual refacing it worked.  It wasn't elegant, but it worked.

This may or may not work for your needs.  And, I hope this is what you were referring to?


Blender Particle system within another particle system

By your description, i imagine that the particles or leaves on the tree won't be moving so you can convert that particle system into a mesh and then apply that mesh as a particle object onto the landscape.


Why does pressing 'Numpad .' not center my view correctly on the selected object?

In your Layout or Modeling viewport, drag out the 'Item, Tool, View' menu from the top right hand of the viewport (has a tiny little arrow pointing toward the viewport, usually to the right of the x y z orientation gizmo). In that drag-out menu, select the 'View' tab and check the 'Lock to Object' text box. If there's something listed there, hit 'X' to the right of it. Now it shouldn't orbit around another point. At least, that was the genesis of my numpad - . issue.


Noise Texture Stretching on Side of Cube

You need to connect your UV map.

Image textures use generated coordinates by default - this makes your texture stretched.
Noise texture works fine with generated coordinates, so it looks okay in your case.

Solution:
1) Add a Texture coordinate node and a Mapping node.
2) Connect your UV map output.
3) Done

Comparison between different variants
Left - properly connected UV map
Center - texture without UV map connected (clearly distorted)
Right - Procedural textures work just fine


How to do texture colors looking the same as in the jpg

You may be getting unexpected results because of the Color Management (in Render settings) - change the View Transform from Filmic to Standard if you want your render to match the input texture

Emission shader is OK, you can also get the same result without adding any explicit shader, just connect the texture node to Surface of your Material Output.


Is blender more superior with the node editor then without it?

For Cycles materials most of the node editor's functionality can be achieved in the material tab. What is missing is the creation and editing functionality of node groups. Also, working in the node editor is much less confusing than using the visualization in the material tab.

For Blender Internal's node-materials, node textures and the compositor there is no equivalent in another part of Blender. If you removed the node editor, you could not use these features at all.


If you are referring to selecting a vert, edge, or face (by way of the 1, 2, or 3 keys respectively), the key you would use for selecting the entire mesh is l (short for "linked"). This will select the entire mesh that is connected to whatever your mouse is hovering over.


why do changes to the armature made in edit mode vanish when I change modes?

Unlike plain objects armature bones have two defined positions. The first position is known as the rest position (or rest pose) and is the position while in edit mode. While in pose or object mode the pose position is used. This pose position is the one that you keyframe to get animations.

While in pose mode any movements are retained as locations relative to the rest position, You can rotate a bone in pose mode then go into edit mode and move it sideways, it will also move sideways in pose mode but will also retain the rotation that was applied before the edit was made.

While in pose mode you can select bones as desired and clear any rotation or location changes to get the armature back to a rest pose with AltG for location and AltR for rotation.

In the armature properties you can also switch between rest and pose position to see any pose alterations.


Scale model so distance between highest and lowest vertices are equal

I would recommend using a script, see this answer https://blender.stackexchange.com/a/156501/15543

import bpy
for ob in bpy.context.selected_objects:
    if ob.dimensions.z:
        ob.dimensions *= 1 / ob.dimensions.z

will set all selected  with z dimension, to z dimension 1.

Note this is making the vertical (z direction) distance between top and bottom verts equal, and doesn't take into account x or y location at all.

  is there a way to do this without scripting?

Equiv of this per individual object in the UI


Hope this helps:

import bpy

# initialize the variables to work with, in this case two selected objects, in yours c1mesh and c2mesh
first_object = bpy.context.selected_objects[0]
second_object = bpy.context.selected_objects[1]

# add the modifier and change settings
first_object.modifiers.new(name = "Boolean", type = 'BOOLEAN')
first_object.modifiers.get("Boolean").operation = "DIFFERENCE"
first_object.modifiers.get("Boolean").object = second_object

# just cosmetic hiding of second object so you can instantly see the result
second_object.hide_viewport = True


How do I join two models together without messing up the texture?

Your are using two UV Maps with different names.

When you join the meshes, the UV Maps will be mantained:

If you want to merge the UV Maps, just assign them the same name before merging.


workflow for creating sculpted tileable Tiles in blender?

I checked also on blender forum. There is currently no simple workflow. Some workflows require offseting the mesh to sculpt over seams.

Seems there's a patch for the issue submitted in 2015, but seems it was not officially accepted yet.

https://blenderartists.org/forum/showthread.php?373956-Wrap-mode-for-Sculpt

If anyone has any idea on how to do that he is wellcome anyway^^.

Seriously thinking to try to write my own plugin, unluckily I'm totally new to Blender python API


Master Z-Depth with multiple render layers

You can use Z combine node to compose Z channels into one.


How to save viewport image when running Blender as Python module

Yes, you can save images rendered from the viewport.
# Set save path
sce = bpy.context.scene.name
bpy.data.scenes[sce].render.filepath = "./image.png"

# Go into camera-view (optional)
for area in bpy.context.screen.areas:
    if area.type == 'VIEW_3D':
        area.spaces[0].region_3d.view_perspective = 'CAMERA'
        break

# Render image through viewport
bpy.ops.render.opengl(write_still=True)

Here are all the different python rendering commands.
A tip for finding out python commands: go into Blender, then Edit > Preferences > Interface tab > check Python Tooltips box. Then you can hover your cursor over any button and the python code command will display as well.
By the way: I am not sure what you mean by 'real-time updated'?


Smoke is not appearing in cycles, neither is the CPU option

The CPU/GPU dropdown selection menu is not visible because you don't have an Nvidia GPU card enabled for usage (either your card isn't Nvidia or it's not enabled for rendering) in the user settings. CPU mode is the default render mode in this case.

If you DO have an Nvidia card installed, you may have to update to the newest drivers for it to show up in your CUDA user preferences selection.


Looking at your image, it looks like your seams aren't marked correctly. You should have an unbroken seem (red line in edit mode) running up the whole of the side of the mesh. This line should connect to a ring seam (a full red ring around the mesh) on each end, that separates the ends from the sides.

As lemon mentioned in the comments, you may also need to follow the instructions in How to make a square grid for UV maps to get even quads in the unwrap.

It may be worth looking at some basic uv unwrapping tutorials.


Edit mode when use Subdivision only show wireframe 2.8

I Suggest You To Use Blender 2.79.Because 2.80 still got many bugs and 2.79 is a stable one . So I suggest You To Use The Stable One. HAPPY BLENDING


Never ever render directly to video... (and avoid AVI as a container  much as you can). There is no way to break down the composited image into its original parts any more, and on top of that a video encoded and image will likely yield errors due to compression.

Use a low resolution/low quality video format just to evaluate the pacing of the animation, but do the final render as an image sequence. That will allow you to avoid situations like the one you are facing where you will have to re-render to make any changes.

If you want to do compositing later, save as image sequences to a format like OpenEXR, in which you can save not only the final rendered image but proper Alpha channel, Z depth information, object and material IDs and whatever other render layer information you want.

Then you can composite as you like and do a final video encoding later.

(read Save all render passes to a single EXR image)


bpy.ops.mesh.primitive_*() operators need to be run in a proper context (3D View) in order to use align_view.

Either run an operator via Spacebar menu, or use an override:

import bpy

for area in bpy.context.screen.areas:
    if area.type == 'VIEW_3D':
        for region in area.regions:
            if region.type == 'WINDOW':
                ctx = bpy.context.copy()
                ctx['area'] = area
                ctx['region'] = region
                bpy.ops.mesh.primitive_plane_add(ctx, view_align=True)
                break

Note that there seems to be a bug, the plane appears to be in Edit mode, but the UI reports Object Mode, and the face may be missing.


How can I bend a mesh so that it curves around other object?

As you correctly guessed, you can use the simple deform modifier, with the bend option. However, you have to change the direction and origin of the bend You can control this by creating an empty and positioning it close to the button, if you select the empty in the origin property of the modifier. Here, I created two deform modifiers, controlled by two empties:

The two empties were made the children of the button, and rotated so that the bending happened in the right direction (to find the right direction, I had to play with the rotation a bit - there is no easy way to understand the correct orientation):

The modifiers look like this (again, I had to try different angles to find a good value):

Here is the .blend file:


How to export a 2D stabilized movie clip?

After setting up and tracking a video in the movie clip editor, you will want to use the tracking data to export an altered video. The adjusted video you see in the clip editor is only an in-memory adjusted version for feedback purposes.

To get a final adjusted video output you will need to setup some compositing nodes to adjust the "rendered" output. The minimum setup you will want is a movie clip input node, a 2D stabilization node and a composite node, a viewer node will let you preview the result behind the nodes if you enable the backdrop option.

Of course you can also add any other nodes to this for colour correction or adding 3D objects etc.

Now when you press render the result will match what is connected to the composite node.


I think the problem is that the objects have a different scale. Select both the curve and the path and hit Ctrl+A and apply the scale. As the Apply Scale will change the curve vertices radius, bring them back to 1 in the 3D View N panel.


Where are the Laplacian Lightning settings once the addon has been installed?

From the addon author's website:

  UI will be in >View3D>Tool Shelf>Laplacian Lightning (object mode)

Make it appear by pressing T (View>Tool shelf) while in 3d view and scroll down to the menu in the Tools tab. It is visible only in Object mode.

If this doesn't work, make sure you downloaded the proper version that match the current Blender version. See the website fore more details.


Open a Command Prompt window and navigate to the Blender application folder (e.g.  CD "C:\Program Files\Blender Foundation\Blender")

Start Blender with the command blender.exe --debug.

You can now see memory usage by pressing Spacebar and searching for Memory Statistics.  This will produce a detailed list of memory usage in the command window used to open Blender:

total memory len: 46.457 MB
peak memory len: 55.115 MB
slop memory len: 5.271 MB
 ITEMS TOTAL-MiB AVERAGE-KiB TYPE
   223 (  13.936    63.992) subsurf arena
  1498 (   8.520     5.824) BLI_Mempool Chunk
     4 (   5.881  1505.508) CDNormal
    14 (   4.996   365.455) imb_addrectImBuf
     1 (   3.000  3072.000) OCIO GPU 3D LUT
    39 (   0.923    24.242) Chunk buffer
  3779 (   0.914     0.248) PropertyRNA
     1 (   0.874   895.125) CDMloopCol
     2 (   0.750   384.016) eh buckets
...


How to create this doted material in cycles

It looks like the Musgrave texture is pretty close to what you want:


Intersecting transparent object causing artifacts in cycles

This is a limitation of many render engines. In OpenGL/DirectX applications it is typically known as z-fighting. The simple answer is to not do this - don't put two surfaces in the exact same place. This is a scenario that's impossible in real life (no two solid objects can share the same location) and therefore typically not taken into account when designing render engines.


How do I prevent the body mesh from protruding through the clothes mesh?

If you don't want any geometry under your model's clothing at all, the simplest thing to do is to export it using the option to hide faces under clothes in MakeHuman.

This way, all faces under clothes will be hidden for you.


Animating with Action Sets and Action Constraints

Here are some finished constraints.
Below Bone.Left has an action constraint.

Below Bone.Right has an action constraint.

In both cases above

[Bone.Control] of the armature is the target bone.
X location is used.
The action name [Armature.C006Action]
All settings are the same because we used one armature and this is intended to be a simple example.

In pose mode keyframes were inserted on Bone.left and Bone.Right on frames 1 and 20.  Inserting keyframes created actions with a name we can use in the action constraint panel.  When Bone control is moved in the X direction here is the result.

The action name came from the DopeSheet/Action Editor Window

In the image above the action name was created. Saved to the Abstract Vault by clicking the letter F next to the name.  The action name is remembered for the constraints.  The action is removed from the armature. Repeat. The action is removed from the armature. If you leave it by mistake the action will dominate the [action constraint] and the flexibility you want will not function.


How to align object well enough to integrate into array modifier?

Joining your objects changed the plane's bounds, using the corridor's bounds. Array modifier is using the object's bounds as a reference (1) for the relative offset. The bounding box can be visible, it's a box containing your complete object.

Your plane is smaller than the bounding box, so it's repeated inside it. You need to fix it's topology to fit the bounds of your corridor.

To do this, activate vertex or edge snapping

Move the needed vertices/edges along 1 axis (Y on my sreenshot) with G, and  X, Y or Z. The mouse cusror will change when close to a vertex/edge it can use to snap

Do the same on the other side

Now your plane will fit the corridor's array.


It's possible to import and use Zbrush sculpt brushes into Blender?

A person did this with the same pack you are talking about
http://www.blendswap.com/blends/view/86419
Here's the link


how to put a object in blender in focus? Viewport focused on the Selected Object

Are you hitting period on the number pad? If your keyboard doesn't have a numpad this thread may be useful in remapping the key:

Emulated Numpad Mapping - Numpad Period?


Setting material node properties across a large number of objects?

There currently appears to be no way to have one material with different settings for each object using it. While an object knows what materials it uses, a material has no link back to the object using it, as a single material may be used by many objects there is also the trouble of choosing which object is currently active.

I see two ways to tackle your problem, one material for each object or a range of materials to be shared across objects. I think a range of materials with varying emission strengths could be generated and one chosen as each object is created. I'm not sure of the range of values in your data, but expect that emission values could be averaged out a bit so that magnitudes within a range could use the same material.

if magnitude >= 100 and magnitude < 200
    obj.material_slots[0] = bpy.data.materials['mag150']


Here is a script that changes direction based on the difference  of angle between first and last spline points and the x_axis.  Run in edit mode.  You may need to change based on which direction to "unify" to.  As is it unifies all curves in the test file you posted to run right to left.  Change either the angle test or the x_axis direction to make all go left to right for instance.

import bpy
from bpy import context
from mathutils import Vector
from math import degrees, radians
curve_object = context.edit_object
x_axis = Vector((1, 0, 0))
# deselect all
bpy.ops.curve.select_all(action='DESELECT')
for s in curve_object.data.splines:
    v = (s.points[1].co - s.points[-1].co).xyz

    angle = v.angle(x_axis)
    print(degrees(angle))
    if angle > radians(90):
        for p in s.points:
            p.select = True

bpy.ops.curve.switch_direction()


Try re-importing it from Roblox, if it was working before the problem might have been the file getting corrupted


Text with cracks and a different material inside

As you say you could use a Boolean modifier to create the cut:

Create your 2 cylinders, give them materials, Curve and Subdivision Surface modifiers:

Create the boolean object, it's a subdivided cylinder with a Displace modifier:

Give your orange object a Boolean modifier, put it on the top of the modifiers stack:


Diffierence between Texture Atlas and Megatexture

Overview

Texture Atlantes and Megatextures might share some similarities but they involve different technologies.

TL;DR: Megatextures and Texture Atlantes are not the same.

Texture Atlas

A texture atlas describes the method of packing several (many) textures of several objects into one big texture. Every object occupies its own texture space on the UV map of this texture atlas.

Megatextures

Megatextures (by the original definition of John Carmack, id Software) are not only huge textures, they also involve a different technology in the game graphics engine and normally are used exclusively for terrain.

Technology

Most game graphics engines use tiling texture chunks to cover the terrain, which might look good from a close range, but (depending on the texture quality) often breaks the illusion when viewed from a distance.

Conventional texturing is quite easy to implement. Besides the already existing texturing techniques it additionally involves blending techniques between different terrain tiles.

A Megatexture due to its size (32000x320000 Pixels in Rage) is able to cover the whole terrain, thus will theoretically not repeat any pattern.

Megatexturing is quite demanding on the hardware and during production process as well.

There is no way that a Megatexture of the size that was used in id Software's Rage will fit in any existing graphics card RAM, so the engine must be capable of not only steaming terrain geometry but also streaming those parts of the Megatexture which are visible on screen. This requires not only optimized hard- and software but also a fast medium to stream from, otherwise you would have visible streaming errors during fast camera rotations.

On the production side you also need hard- and software that is capable of dealing with huge image sizes.

id Software's next step in the evolution of their id Tech engine is called Virtual Texturing, where the Megatexture not only cover the terrain but every single model in the game itself. The texture sizes can reach 128000×128000 pixel and more.


How do I change the default settings of export operators?

You don't necessarily need to write a custom operator to re-use the existing one. You can call the operator in your layout and change its properties, see How to pass multiple operator properties via UI layout?
import bpy

class HelloWorldPanel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "Hello World Panel"
    bl_idname = "OBJECT_PT_hello"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "object"

    def draw(self, context):
        layout = self.layout
        op = layout.operator("export_mesh.stl", text="My Custom STL Exporter")
        op.use_selection = True
        op.batch_mode = 'OBJECT'

def register():
    bpy.utils.register_class(HelloWorldPanel)

def unregister():
    bpy.utils.unregister_class(HelloWorldPanel)

if __name__ == "__main__":
    register()

You can find the operator's parameters in your blender install path / 2.** / Scripts / addons / io_mesh_stl / __init__.py under the ExportSTL class.  :
use_selection: BoolProperty(
    name="Selection Only",
    description="Export selected objects only",
    default=False,
)
global_scale: FloatProperty(
    name="Scale",
    min=0.01, max=1000.0,
    default=1.0,
)
use_scene_unit: BoolProperty(
    name="Scene Unit",
    description="Apply current scene's unit (as defined by unit scale) to exported data",
    default=False,
)
ascii: BoolProperty(
    name="Ascii",
    description="Save the file in ASCII file format",
    default=False,
)
use_mesh_modifiers: BoolProperty(
    name="Apply Modifiers",
    description="Apply the modifiers before saving",
    default=True,
)
batch_mode: EnumProperty(
    name="Batch Mode",
    items=(
        ('OFF', "Off", "All data in one file"),
        ('OBJECT', "Object", "Each object as a file"),
    ),
)


Flip Fluid addon [$]

create star (you can use Extra Objects addon) and animate movement
under Physics Properties enable Flip Fluid > type Inflow
add Cube object and scale it to Domain dimension
under Physics Properties enable Flip Fluid type Domain
under FLIP Fluid World enable Viscosity
Bake

Credits for Cup-Cake model goes to MrSorbias.

Mantaflow
in general same system (domain / inflow). I just wasnt able to setup enough viscosity without strange behaviour of particles. This area doesn't seems to be covered in Mantaflow solver. You can find a parameters in Physics Properties editor under Diffusion, but from what I saw on net, most thick liquid is still too far from cream with ability to keep a form.
For more details check this intro


Cannot find displacement in material panel - blender 2.83

You need to change your Render engine, that option is only for Cycles
Go to Render Properties > Render Engine


Mirror an object so that key framing is possible?

This can be done without mirroring by simply creating two unique objects and then adding a Transformation constraint to one of them.

What this constraint does is allow you to map any transforms of one object to any transforms of another object. In some ways this can be easier than setting up drivers. Here, the Y location part of the constraint is inverted, while the Z and X location parts are mapped one-to-one.

In the included Blend file, I have two spheres. The one to the far side of the center plane is Transformation constrained to the sphere on the near side of the center plane. The pic below shows the settings I chose to get the sphere on the far side of the center plane to mirror the motion of the one on the near side. By selecting and keyframing the sphere on the near side of the center plane, the other sphere will follow (but won't have keyframes of its own).

If you choose to play with the file, note that I added a second constraint, a Limit Location constraint to the near sphere, but this has nothing to do with your problem. So don't let its presence mislead you. I just thought it would fun to see the near sphere bump into the center plane and go no further, as if there was a real mirror in the middle, and the far sphere was merely a reflection of the near one. :)


Object not rendering smoothly - Can see where it bends regardless of how many loops cuts I have

The imperfections are inherited from the curve used in the curve modifier. Select it, go to edit mode, select all and then search(f3) for Set Spline Type operator and set to NURBS:

You will also be able to control the resolution of it in the curve properties tab, but default 12 should be fine.
Or you could also solve the problem by moving the subdivision modifier below the curve:

I would recommend to do both - make the curve smooth and also use the subdivision modifier in the right order.
Just to clarify: by "right" order I mean probably the more efficient way - first modify the less dense geometry by curve modifier requiring less computation and only then smooth it by subdivision also increasing the density. I might not know some of the context to use such strong words as "right" ;)


Lossless 10-bit colorspace (yuvj420p) video output

You can't.

When working on footage, it is always most prudent to operate on the frame level, with controlled decoding to the file format you choose. Codecs always have been and always will be an awful choice.

Currently in Blender, all codecs via the VSE (and otherwise I believe) are decoded using the FFMPEG call that converts them to an 8 bit buffer.

So, decode outside to a suitable 16 bit container such as TIFF, then properly linearize the results via a controlled transform.

Also, “8 bit” is not a colour space, nor is “10 bit”, nor is “float color space”.


Is AMD Radeon graphics card supported with Blender 2.90 on Mac?

Preferences > System > Cycles Render Devices and select OpenCL. You can also try AMD ProRender: https://www.amd.com/en/technologies/radeon-prorender-blender


Set hotkey to move perpendicular to normal/slide on surface

Not sure exactly what that key combination is supposed to do nor if it is supposed to be used in Edit Mode or Object Mode specifically, but go to the User Preferences > Input look for the relevant context under the 3D View category, like Global, Object Mode, or Mesh etc.

Either add a new entr there using the Add New button at the bottom, or modify an existing.

Pick the relevant operator, I am guessing transform.translate, expand the settings bellow and adjust the available controls to your liking.

I supposed the Constraint and Align with point Normal are of particular interest to you.


Trouble deleting mesh parts from sculpting -From symmetric View

You could remove the vertices in Edit Mode and use Symmetrize function to make identical changes on the other size.
Select the pinching vertices and delete them. Fix the hole that was left behind. Select all a and under Mesh select Symmetrize. In your model x asix is up so you need to use Symmetrize direction +Z to -Z to make the other arm identical.


Is there an easy way to align two objects on a specific axis?

You can use Align Objects available in the 3d view header under Object > Transform > Align Objects.

This will bring up a panel in the toolshelf and you can choose the axis to align the selected objects on. You can also choose to align relative to and the mode to align by.


If you drag character, rig stays where it is

If you drag armature instead, character follows it


What algorithm does Blender use to simulate the interaction between fluid and object?

The wanted information were found by both googling the keywords "blender fluid simulation" which leads to this page of the 2.4 documentation and some grep in the source code of Blender.

In this doc page, you can see a "technical details" chapter which indicates three algorithms :

Lattice Boltzmann Method (LBM)
Navier-Stokes (NS)
Smoothed Particle Hydrodynamics (SPH). SPH seems to be approximations to the Lagrangian formulation of the Navier-Stokes equations

From that, I did only grep in the Visual Studio solution (don't imagine a minute I know anything more about all that...). For instance :

To summarize :

LBM is in simulation_object.cpp
SPH is in particle_system.c


Using an object as a clipping mask for another object

With a scene set up like your image, a wedge shape and the curve shape with an array modifier; I created the mask with the compositor.

I have a fully transparent material on the wedge, and the material pass set to 1 (object index pass would work here as well.) Do note that the wedge's top face has to be above the curve shape for the IndexOB or the IndexMA to give a usable mask.

In the compositor use the material, or object index pass as a mask by multiplying (a Mix node) it with the image's alpha (because the material index pass is set to one there is no need for a Id Mask node). Then take the black and white masked image from the mix node and use it as the image's alpha with a Set Alpha node.

Here is the result after using the IndexOB as a mask.


Certain problem in this case might be different but if unnecessary geometry is only composed of edges you can subtract selection based on selection modes.
Deselect all, enter Edge selection mode, select all. Then enter Face selection mode. Selection will be edited accordingly as edges can't be selected in Face selection mode. Switch to Edge selection mode, invert selection, delete edges.

There are other ways to delete loose geometry, one way is to use Select > Select All By Trait and use options there.


Append an object without its associated objects

While apending, in the file browser, untick the option Localize All at the bottom left settings panel.


Is there a way to modify multiple curve slopes in Graph Editor at the same time?

Select the keyframe (which selects both side handles) press C for Circular Selection tool and de-select the side you don't want.


Constructive modifiers (like solidify) only create new verts after applying. So you have to apply them to edit the new geometry.
Form the [blender Manual:]
(https://docs.blender.org/manual/en/latest/modeling/modifiers/introduction.html)

Apply
Makes the modifier “real” – converts the object’s geometry to match the applied modifier, and deletes the modifier.


The mesh parents were off center, and were fixed by moving them to the 3d cursor. Huge thanks to Pte Jack for figuring this out.


How to make 3D model fully distributable

This could depend on how you expect people to see and interact with your model, and how simple the process you wish to be but come to mind:

making it a distributable "blender game" (an interactive environment), but requires skills, experience and does not support all cycles features, eg. Your recipient could download it and "play it" locally.
see:
http://www.blender.org/manual/game_engine/licensing.html#standalone-games
http://wiki.blender.org/index.php/Doc:2.6/FAQ/Game_Engine/Standalone_game
using services like https://www.blend4web.com/en/ which require no plugins (is even gpl so you can even host your own)... Your recipient could just visit a page and interact in the browser with the model. (examples: https://www.blend4web.com/en/demo/)
another similar service (but not gpl, afaik) is https://sketchfab.com/


I eventually found the answer through trial and error, here was my solution:


You can "snap to face" :

Then move each vertice to the face :

And have this result :

But it wont automatically rotate or anything.
For "rotation" or other smoothing effects on the shape, this is to be done manually (I am quite sure there is no other way to do it, except if the rotation aspect is clarified in the question).


Animating several objects randomly moving across the surface of another object

Use two objects: your shape (are they $s$ and $p$ atomic orbitals?) to generate particles, and a fattened version of it to contain them.
Result:

(workbench)

(eevee)
Procedure
Emitter object
On your main shape, add a Particle System. Things to change with respect to the defaults:

Emission > "Frame End" must be 1 (all particles emitted at the beginning of time), "Lifetime" as long as you like
Emission > Source > "Emit From" should be "Volume"
Velocity > "Normal" should be 0
Physics > Forces > "Brownian" to some value around 3
Field Weight > "Gravity" to 0
Render > "Render As" to "Object" (then select a UVSphere to duplicate)

Container object
Duplicate your main object, and remove the Particle System from the duplicate.
In Edit Mode, use the Shrink/Fatten tool (you can find it using Search or in the T toolshelf) and fatten it a bit. Then invert its normals: CtrlShiftN so that they point inwards.
In the Physics panel, activate Collision. Default parameters work well.
Since this is an helper object, you may want to restrict its render visibility in the Outliner, and to make its Viewport Display > Display as Wires in the Object properties.


What is the math for the B-spline interpolation of a color ramp with two color stops?

Implementing B-Spline is quite a bit beyond my maths capabilities but a simple 'ease' is certainly feasible. To achieve this you can calculate the 'influence' of each of the control points and combine these to produce the overall influence. Varying the parameters controls the shape of the curve.

I've created a Desmos example which can be accessed here : https://www.desmos.com/calculator/orfi1cybkc and is as shown in the following image :

Breaking this down a bit, we start with two points along the x-axis defined as p1 and p2 along with associated values v1 and v2 so each point is defined as (p,v). These can be adjusted and positioned as desired.

To determine the 'height' (y) at each point along the x-axis we need to determine the relative influence of each point. For this we first determine the distance as d = abs(x - p) for each 'point' (p1, p2).

The variables w and E (exponent) control the shape of the curve. w is present to avoid divide by zero errors by ensuring there is always a small offset from zero, while E controls how the influence of each point drops off over distance. Each influence is determined with :

i = 1 / (w + pow(d,E))

Once we have the 'influence' of each point (i1, i2) we can combine them with :

y = (v1*i1 + v2*i2) / (i1 + i2)

To build the nodes I opted to use the Dynamic Maths Expression add-on developed for this answer which can be downloaded from here. The add-on allows you to simply type an equation and the corresponding nodes are automatically built within a node group hidden behind the node. This allows complicated expressions to be very easily constructed.

For instance, for the 'influence' calculation I used the following equation :

Influence=1/(w+Distance**Exponent)

This produces the following node :

Within the node are the following generated nodes to implement the specified expression :

Similar can be done with 'Distance' and 'Output' as shown in the following (all wrapped within a Group for convenience) :

This node group can now be used to produce the required 'easing' curve as demonstrated with this example :

Using an exponent of 1.0 will produce a straight line :

Exponents greater than 1.0 will produce increasing curve :

1.5

2.5

4.0

Exponents less than 1.0 will produce the opposite curve :

0.5

Two blend files are included - one that requires the Dynamic Expression add-on and one that does not require the Dynamic Expression add-on (the 'internal' node groups have been transferred into standard node groups) :

Using Dynamic Expression add-on :

Stand-alone (without Dynamic Expression add-on) :

EDIT
Note : Rather than using multiple Dynamic Expression nodes within the group you can actually combine the maths into a single expression (by substitution) and use this in a single Dynamic Expression node :

Output=((1/(0.001+abs(x-Point1)**Exponent))*Value1+(1/(0.001+abs(x-Point2)**Exponent))*Value2)/((1/(0.001+abs(x-Point1)**Exponent))+(1/(0.001+abs(x-Point2)**Exponent)))

This avoids the complexity of the additional level of node groups but will be slightly less efficient (due to the 'influence' needing to be effectively calculated twice for each 'point'). Note also that the add-on creates the node with the input variables in the order they are presented in the equation and this results in 'x', 'Point1', 'Exponent', 'Value1', etc. - rather than a more intuitive sequence. Being able to specify the order of the input sockets would be a useful addition to the add-on.


How do I get rid of right click context menu

In Edit > Preferences > Keymap, you can change the 'select with' parameter to right. Left click will automatically change to Cursor. This used to be the default behaviour till version 2.79


Given the image, and the fact that subdivisions help, I'm inclined to say that it's a terminator problem.
Sadly, it's a common problem on most ray/pathtracers, so your solutions are:

Increase subdivisions.
Increase light sizes. This will make shadows softer, and will mask the problem a bit.
Use a non-tracer renderer (like Blender Internal or, maybe Eevee), that doesn't have this problem.


How to hide Stencil in Texture Paint Mode

As far as I know, you can't make the stencil disappear using any shortcuts. What you can do is grab it (hold RMB and drag the mouse from left to right), then place it on a right/left side of a screen. You may see only a small fragment of it. Then you can grab it again and place back on the previous position.


Connect Hip Bone to the Tail of Backbone

Like Sambler eluded to, parent the hip bones to the backbone without being connected.  This is also known as 'Keep Offset'.

Get into Bone Edit mode.
Select Hip_L/Hip_R bone.
Select Backbone.
Hit Ctrl+P and from the menu select Keep Offset.

Here's the result of the above steps, repeated for both hips.


You can also do this without any addon.
Just use the Material Override option in Cycles.
It will render all objects with the selected material.

1) Create your Clay material.
2) Select it in the Material Override panel.
3) Select how many samples you want to render (0 will use the scene settings)

Material Override with a material selected.

Material Override currently works in Cycles only, Eevee doesn't support this feature.


Is there a way to scale up a collection of objects individually in random intervals

your collection should have the name "Automatic_frames" (or you just change the name in this script to your collection's name).
It does not check, whether you already have keyframes...so if you ran it twice, each object will scale two times and might overlap. Of course you can change the frame_from range to your needs.
you can do it like this:
import bpy
import random

for eachObject in bpy.data.collections['Automatic_frames'].objects:

    frame_from = random.randint(100, 400)
    frame_to = frame_from + 40

    eachObject.scale = (0,0,0)
    eachObject.keyframe_insert(data_path = 'scale', frame = frame_from)

    eachObject.scale = (1,1,1)
    eachObject.keyframe_insert(data_path = 'scale', frame = frame_to)

possible result:


These lines show relations between objects. I think in your case these are parent-child relations, which means that in the bottom left corner there is an object (parent) that, if you move it, moves all the other objects (children) with it.
You can disable that these lines are drawn.
In the Overlays for the viewport you can disable Relationship Lines.

Also have a look at the outliner window in the top right of your screen. It can tell you much about the scene:

If you expand the item by clicking on the small triangle left of the name of the object, you will see the objects that are parented.

If you want to make any of the parented object a completely independent object, then you can select it and press ⎇ Alt+P and clear the parent relationsip.

For Version 2.7
Press N while your mouse is in the 3D viewport to bring up the Properties shelf. Then scroll down to display and disable Relationship Lines:

If you also want to deactivate the transform widget look for the marked button at the bottom of your 3D viewport:

Alternatively you can activate Only Render. Then anything that is not mesh data will be hidden, except for the transform widget.


Why does home button in the UV/Image editor zoom out a lot?

As far as I remember, it snaps to the same zoom ratios as you use the numpad for (1:1, 1:2, 1:4, 1:8...). This is probably to avoid any scaling artifacts since the Image Editor does not filter the images.

If you want to view the image fit to the borders better, try pressing F. However this will not set it to 1:1 if the image is smaller than the region.

Personally, I think there could be some more consistency in this regard, keeping the same hotkeys throughout editors would be nice.


How can I apply a ripple effect on the screen/camera (not on puddles or rivers)

You can also use dynamic paint to obtain many ripple effects in a more flexible way than using the compositor uniquely :

The usage may be different from the one you could obtain with the compositor, but this approach can interest you.

Here is the settings :

A plane, with a subsurface modifier (set to 'simple' in order to keep it angular)
And a dynamic paint modifier

In the physics panel of the plane, set the dynamic paint to canvas, then to wave and eventually adjust the parameters :

Make another mesh (or several, here I used a sphere) and add it also a dynamic paint modifier, but this time set it to brush :

And you are done : simply move the brush object into the canvas surface and it makes ripples during the animation (you need to run the animation to obtain it).

You can mix it with your animation, using for instance a glass shader, or putting it in another layer and merge it with the compositor.


This is possible using a Fluid simulation - although it does take a bit of trial and error to get the settings right whilst still being able to keep the simulation resolution low enough to make it practical.

To set up the scene you need the Fluid domain and the 'nozzles' to spray the water. The fluid domain should be kept as small as possible to reduce the computation for the simulation. Note that if you resize the domain you should always 'Apply Scale' for the resizing to take effect on the simulation cells (otherwise the simulation will be distorted).

I used the 'Shell' setting for the Inflow nozzles. This allows them to be defined as simple plane faces rather than a volume within the simulation. The sizing and orientation of the nozzles is quite significant - they need to be big enough in relation to the fluid 'resolution' and the direction of the 'Inflow' should approximately match the orientation of those faces.

The higher the Resolution of the fluid simulation the better - although larger values will significantly affect the simulation bake time. However, the resolution must be high enough in relation to your inflow nozzles so that each contributes a solid stream of fluid. If the inflow is intermittent, try larger nozzles, reorient the nozzles to match the flow direction, or increase the resolution.

Once you have the general flow working you will likely need to adjust the Inflow speed and direction (by changing the X,Y,Z Velocity settings) to adjust the flow. This needs to be high enough to produce enough fluid to cover the surface without being too high to cause splashing (which will hit the edges of your domain and look ugly). One trick to prevent splashing is to increase the compressibility of the fluid, allowing the fluid to spread into an area rather than bounce off the existing fluid (technically not physically accurate for water but produces better effects without having to drastically increase the domain resolution).

For simplicity I used the back face of the domain as the 'surface' for the water wall rather than a fluid Obstacle. I added the 'fake' glass pane behind the domain for the final render - it doesn’t interact with the simulation. This simplifies the simulation as there are no complications of the collision surface not aligning with the cells of the simulation. Add an Outflow mesh to the bottom of the domain to drain away the fluid. Don't forget to set your domain mesh to 'Smooth' (or you'll get angular fluid).

Bake the simulation and assign suitable fluid material (essentially just slightly coloured glass).

Here's the final result baked with a resolution of 300 :

Blend file included


Render Quality is amazing but video is poor quality and really grainy

The most probable cause for this issue is bad video compression. Here are my favorite settings for rendering video.

I would recommend rendering an image sequence instead though, since that offers better formats such as .png

Note:
It is nearly impossible to confirm what is wrong without you posting more information.


Map a procedural texture like an image texture

Blender Internal:

Yes, procedural textures can be projected the same way as image textures. In the texture tab, scroll down the procedural texture's settings to the Mapping group. You can find the projection and axes drop downs there.

Cycles:

Cycles does not offer shape projections (cube / sphere / tube / flat), but using but a Texture Coordinate Input node set to Generated or Object, and a Vector Mapping node, a similar effect can be achieved. Just play with the scale and rotation values to fine-tune the effect:


Rig perpendicular armature movement along vertical axis

Overview

This rig is quite simple, actually. It is a single chain of bones for deformation with a few miscellaneous bones for animation control. This answer is a walkthrough of my process in creating the rig. For a point of reference, a rig is a series of bones built to deform a mesh for animation.

Rig the mesh using Inverse Kinematics (IK). IK allows the bone at the end of the chain to be manipulated directly. Positioning the end bone causes each bone between it and the top of the chain to be repositioned automatically. This contrasts with FK (Forward Kinematics) where you position each bone in sequence from the top of the chain to the bottom.

Solution

In the proposed solution there are a few items to note: (1) the head of the robotic arm is named sphere; (2) the topmost bone is named tip; (3) the target bone is named ik-target; and (4) the armature is called ik. Then:

Create and align bones with the mesh so that rotation is restricted to one axis.
Add an IK constraint to tip.
Create (duplicate??) the ik-target bone from tip.
Parent
Give sphere a target of ik-target.
Ensure ik-target is parented under ik.

Then I started locking the bone axes I can't use. These are the axes that rotate in a direction that would break the mesh joints. These were either the X or Y axis, depending on the bone. Take note of the axis I locked and notice which direction it is supposed to rotate in. I did this in the bone properties, under the IK section:

This keeps the IK solver from using these axes when it calculates the position of the middle bones. For easier axis management, I changed the rotation method of all the bones to XYZ Euler instead of Quaternions. Eulers are suitable in this scenario because of the single-axis nature of a robot.

Lastly, add a copy rotation constraint on tip with a target of ik in World Space. This enables intuitive rotation of sphere while maintaining the translation.

This rig is simple and must be expanded to get every function available in the robot. Animating the head will need another bone hierarchy. There is a special case where the robot rotates the head around the tip of the probe. This will require another rig layer.

Feel free to use my rig if you wish.

Notes

There are two rigs, one on each layer. The first layer is an FK chain, which is fairly simple and only uses a parent hierarchy to move the mesh. The second is the IK rig, which I described above. I was going to recommend using the FK rig because of its simplicity, but the functions you want are fairly complex to animate in an FK chain.

Example Blend File

Pick apart the sample file to get started:


Im making many objects one model, while still looking like many different Objects, How would I do that?

Join them together.

Select the first initial object by right clicking on it then subsequently selecting the rest (by right clicking on them) while holding the shift key. Once each object that you want in the same object is selected, press CTRL+J.

(This is all assuming you have left the key shortcuts their default values.)


Use of Curve Modifier to Make G2 Timing Belt

Thanks to @moonboots for the comment pointing me in the right direction.
The answer was to go into edit mode for the curve, select all the points, and then set the "Mean Radius" for all of the points in the curve to 1.
If you "apply" a scale to a curve object, the radius of all the points is subsequently changed from its previous value to a scaled version of the radius.  Blender is simply "applying" the scaling factor you have selected to some of the internal properties.  For example, if you scale your curve by 0.5, then the radius for each point is then changed to 0.5 times its original value.  Typically, the radius is set to 1 (unless you are doing something interesting and fun).  Then when Blender uses the curve in a curve modifier, it will scale the original object by the values in the radius as it is placed along the curve.  This is why setting the radius back to 1 (i.e. no scaling) fixes this problem.


Sculpted mesh reverts to original shape upon exiting sculpt mode

This seems to have been a display error. I entered edit mode once, which fixed it. It was a fairly big mesh, so I could imagine that the display error happened due to insufficient power.


Trying to bake mesh results in "Circular reference in texture stack"

For anyone experiencing the same problem: most likely you are trying to bake to a texture already used by material, even if you see different texture in the UV/Image Editor. Make sure to select all faces in the UV editor and then create (Image > New Image) or select the target texture for baking.


How to create a GUI based window in Blender Game Engine that displays text?

You can try to follow some Tutorials like for a HUD, a Health Bar or maybe some Word Wrapping of a text overlay...


You have two separate objects. To join them you have to enter the object mode first. On the screenshot, the selected bone (and it's armature) is in edit mode. Press ↹ Tab to go into object mode or choose Object Mode from the footer menu of the 3D view.

When you are in object mode you should be able to select both of the armatures by ⇧ Shift RMB clicking. When both are selected (and highlighted) you can join them by pressing ⎈ CtrlJ. All objects of the same type can be joined in object mode with ⎈ CtrlJ. Now you can enter edit mode again (↹ Tab) and select both bones.


Objects intersecting in render but not in viewport

it depends on your frame.
With starting frame 5 i see water in your boat in viewport...

it looks like you applied the boolean modifier. I wouldn't have done that.
And if you apply, you cannot change it afterwards.
And i think - if you apply, it is "just for the moment". But unapplied the boolean modifier will also work for animated objects.


Is it possible to set the pivot point origin of an object in BGE with python

When you mean the object's origin: No, you can't (and it makes no sense).

When you mean the rotation center, you can:

combine the rotation with a translation (= orbiting)
parent the object to another that acts as rotation center. Turn the parent rather the child.

When you mean the pivot point of a a rigid body constraint, I do not know. The API does not look like you can. An alternative would be to remove the current constraint and create a new one with the pivot at the new location.


You got individual origins set as Pivot center for rotation/scaling,that's why you're getting this weird behaviour. Switch it to Median Point if you want vertices to make straight line in common middle.Check also other options. I find Active element very useful in similar cases.


In case this is usefull, I used a script to track the mouse and move an object which acts as a cursor independently.

import bge

cont = bge.logic.getCurrentController()
mouse = cont.sensors['Mouse']
cursor = cont.owner

width = bge.render.getWindowWidth()
height = bge.render.getWindowHeight()

mousex =  float(mouse.position[0])
mousey =  float(mouse.position[1])
x = (mousex  / (width/2))  -0.75426
y = (-mousey / height) +0.35371

cont.owner.worldPosition = ((x), (y), (0.0))


It isn't hard to make a list of missing images, removing them from bpy.data.images isn't always easy. The image knows how many times it is used but not where it is used, you will need to look through textures and nodes to find where it is used to clear the users before you will be allowed to delete the image.

I would suggest testing the existence of the image before packing rather than trying to cleanup the blend file. Use bpy.path.abspath() to get the true filepath for the image (this turns '//' into a real filepath) and then use os.path.exists() to check if there is a file you can pack.

import bpy, os

for i in bpy.data.images:
    if i.filepath:
        ipath = bpy.path.abspath(i.filepath)
        if os.path.exists(ipath):
            i.pack()

As you come across a missing image you could add it to a list and report the missing files when you are done. Maybe create the list in the text editor for the user to look through.


Suggestion to rig & animate skin+bone+muscle at the same time?

If the skin mesh is low or mid-poly:

Rig the skin with bones (automatic or manual weight painting).
Control the muscles inside the skin with Mesh Deform modifier set to skin object.
Parent the bone meshes to rig bones, they do not need to deform.

If the skin mesh is highpoly (ie. scanned or sculpted mesh):

Build a low poly envelope around your arm.
Control both the skin and muscles through Mesh Deform driven by the low poly.
Parent the bone meshes to rig bones.

The Mesh Deform modifier will ensure that the muscles will stay inside the skin and will deform correctly. You can add shapekeys to the muscles and skin to make them flex and preserve volume.

It is difficult to weight paint multiple meshes to the same bones to have the same deformation. The automatic heat-driven weigh painting will fail on separate meshes - this works well only on volumetric auto-weight painting that Maya has.


How do you stop an adjacent face from moving?

For what it's worth : after using Blender for about a year, I have personally never encountered the behavior shown in that tutorial picture - that is to say, performing a "Sketchup-like" push and pull with an automatic fill.

A third-party add-on allowing for something of that nature has recently been released, but this is definitely not default. This probably means that this tutorial has been badly edited/proofread.