I actually found a way to track all operations by typing

bpy.app.debug_wm = True

in the script window.

From this, you see too much information, but you can see the actually operations.

To export with

Babylon.js: bpy.ops.scene.babylon(filepath="test.babylon")
STL: bpy.ops.export_mesh.stl(filepath="untitled.stl")

Hope this will help other people.


How to fix irregular cross section and shape-stretching while curving a mesh?

You could do it this way:

Create a torus with 6 Major Segments. Rotate it 90° on the X axis and 30° on the Y axis. Apply the rotation with ctrlA.
Duplicate it and keep a half somewhere.
Cut the 2 extremities with the knife (K to activate, Z to cut through, C to cut perpendicularly), separate in the middle with V, move one half and create an X.
Give your shape an Array modifier with a Count of 7, activate the Merge and First Last options.
Give it a Simple Deform modifier / Bend mode, with the angle you want, for example 280° if your final shape is not closed.
As you will want to smooth it with a Subdivision Surface modifier, add some edge loops to your mesh to sharp the edges.
Give it a Subdivision Surface modifier, smooth it.
Keep a copy of your object somewhere. Apply the Array and Simple Deform modifiers on the original.
Bring back the half torus you've created at the beginning and stick it to each extremity of the shape with the help of the Snap option / Vertex mode and Automatically Merge Vertices option.
Go in Edit mode, select all and W > Remove Doubles.


Screw modifier not following spiral curve

The problem is caused by the mesh and the curve not having the same origin.
Once the objects are aligned, the spiral has constant width.

One way to make the objects share the origin is:

Select the curve, press Shift+S and choose “Cursor to Selection”
Select the mesh, press Shift+S, choose “Selection to Cursor”

Kudos to David for finding the solution for an answer to a similar question


How to emulate a Number Pad and 3 Button Mouse?

Blender has options that allow you to emulate both of these features. If you go into the User Preferences view and select the 'Input' tab, you should see a bunch of options on the left side of your screen. To use the numbers across the top of your keyboard instead of a number pad, select 'Emulate Numpad.' To emulate the third mouse button, select 'Emulate 3 Button Mouse.' What this does is allows you to press the Alt key while using your left mouse button, and have it behave just like the middle/third mouse button.

Ultimately however, if you're going to be using Blender heavily, you're going to want to get a real three button mouse and/or a numpad. I would personally heavily recommend getting a USB or wireless three-button mouse from a office supply store--they're really cheap, and it saves a ton of time over the Alt-click setting.


How to properly rig the shoulder of this low poly model?

You need to :

Go in Edit mode, some normals are flipped, recalculate them
Add some edge loops so that your armature is able to bend the object:

Reparent With Automatic Weight
Bring some corrections in Weight Paint mode


How to scale a side of already subdivided prism?

There are various tool that can help you in this kind of operation. Here's four that come in my mind:

Proportional edit:

  Proportional Edit is a way of transforming selected elements (such as
  vertices) while having that transformation affect other nearby
  elements

While in edit mode, enable Proportional editing with the faces to scale selected. Choose "linear" interpolation type, scale on the wanted axis and than adjust the influence radius with the mousewheel.

Lattice modifier

  A lattice consists of a three-dimensional non-renderable grid of vertices. Its main use is to give extra deformation capabilities to the underlying object it controls

While in object mode, add a Lattice object to the scene and set its' vetex number to 4. Position the lattice upon the starting mesh and scale it as it would be the obect's bounding box. Add a Lattice modifier pointing to your lattice to the objecte. Then enter in Lattice's edit mode and move the top vertices toward the center.

Simple deform modifier - Taper

  Linearly scales along Z axis.

Add the modifier to your obhect and choose Taper mode. Lock X scale (or Y) to prevent deformation on both axes and adjust other parameters on your need.

Shear (or scale on axis) the whole face


When you add Collision in the physics properties this includes settings for interaction with Cloth and Soft Body - the Inner and Outer values.

These are typically in Blender Units (or whatever units you have your scene set to) so 0.02 Outer would relate to 2cm if 1BU = 1m. You therefore may need to review your collision settings for the scale. Also, always ensure you Apply Scale on your model and cloth objects.


How to achieve translucent pomegranate material?

Let's think like a photographer.

Proper lighting is essential - white background, strong backlight, fitting HDRi
Shader - Principled BSDF will do (let's keep it simple)
Use post-processing - adjusting midtone contrast, color-corrections

Outer Seed shader:

Roughness - pretty low, it needs to reflect environment and not
obstruct transmission
Clearcoat - just an artistic choice, as the outer seed has a thin glossy skin
Transmission - full 1
IOR - 1.6
Trans. rougness - 0,1 to distort the light a bit more

Notes:
When going for proper realism you'd use Volumetrics, Subsurface scattering and some textures for a more organic look.

But all things considered, proper lighting is everything here :).


is it possible to divide shapekey to small ranges?

i found the answer
best way is  add iris texture on eyeball (shrikwrap modifier not working in unity)
then  import model in to unity  , in unity add texture to eyeball material ,
for moving the iris must offset the texture from inspector and for eye movements must make animation from windows->animation->animation

making shapekey for iris is not a good idea.


Unwrapping car problem, overlapping faces and uv "spaghetti"

You have somehow managed to Pin some of the unwrapped vertices. That’s the red dots that appear in the UV editor. They are not really showing in the image you posted but show up in the .blend file you provided.

What you need to do is Unpin them and then UV unwrap again.


Single Object transparency overlay with additive/brighter coloring

You can try to tune this simple material setup:

This example is based on the simple idea covered at this post:
https://blender.stackexchange.com/a/88356/13643


As LukeD mentioned, you could make your way with what he pointed out. Depending on your skill level, you may succeed or be completely discouraged.

There's a full tutorial from Andrew Price (blender guru) teaching the whole work flow of the steps mentioned in the later comment.
https://www.blenderguru.com/tutorials/how-to-create-realistic-bread

Yep, it's not for a rough bark but the work flow should help you taking care of some details and difficulties you may encounter during the process.
Replace all the words "Bread" with "Wood" and you'll be good to go!
I guess I saw some wood textures that may help you out on textures.com, it's free for low res.

Good luck!


How to see object from multiple perspectives in real time

You can use the Quad View mode in the 3D View, just go to View > Area > Toggle Quad View (Ctrl + Alt + Q) to activate.

To keep the views in sync you can toggle on the Box option under the N 3D View Sidebar > View > Quad View > Box.


How to make a realistic droplet drop on leaf?

Softbody and a cloth object with collision enabled to produce feedback beween the simulations.
https://gyazo.com/f513d99f530abdf3e178121fdb298b02


What causes this very dark areas, that can't be shadows?

This can be the result of overlapping geometry - causing Z-fighting where two or more faces are in the exact same location and orientation. This can result in the faces shadowing each other and other artefacts  such as banding.
Check your meshes and objects to see if you have a duplicate mesh at the exact same point (try selecting one and move or hide it to see if the other remains) or whether your mesh has multiple overlapping faces (move a vertex and see if another face is in the same place).


Liquid / glass interface IOR and normals in Cycles

The answer seems to be yes. This is a fairly commonly used technique, it works with LuxRender and Yafaray as well.

Here is an example rendered in cycles with the normals and materials setup like the autodesk example:

  Air-Glass interface (IOR = $\frac{1.5}{1} = 1.5$)
  Air-Liquid interface (IOR = $\frac{1.33}{1} = 1.33$)
  Glass-Liquid interface (IOR= $\frac{1.33}{1.5} = 0.8$)

  It is evident that in the most common case of an interface with air, the IOR to use is the IOR of the media (since the IOR of air is 1.0), whereas in an interface between two different media, the situation is different.

It seems that the basic thing to keep in mind is that the interface IOR should be equal to:

$$
\frac
{\textrm{IOR of medium with normals facing }\textbf{away}}
{\textrm{IOR of medium with normals facing }\textbf{towards}}
$$

If you set up the normals the other way around, (e.g. here) it is the opposite:

$$
\frac
{\text{IOR of medium with normals facing }\textbf{towards}}
{\text{IOR of medium with normals facing }\textbf{away}}
$$

In the autodesk example, Liquid (with an IOR of 1.33) is divided by Glass (IOR of 1.5), because the normals are facing the Glass medium.

Yes, you do need to use separate materials and IOR values for each surface type.
Assign the materials to the appropriate faces:

The Air to Glass material, the Air to Liquid material, and the Glass to Liquid material:


Looking for help on how to use the new denoising data

I asked over on the devtalk site and recieved this answer from Brecht Lommel:

  It’s intended for the upcoming feature of animation denoising, where denoising happens in a post processing pass ones all the frames have been rendered. It doesn’t really have a purpose outside of that.

https://devtalk.blender.org/t/how-can-the-new-denoising-data-be-used/3071


First, the mesh of your belt is not closed, you should delete some vertices and use W > LoopTools > Bridge. Also, it's not parented to the good bones. You should join it to the rest of the body ctrlJ, select your belt in Edit mode, remove from any group in the Properties panel > Data > Vertex Groups and Remove From All Groups function, then in Weight Paint you assign it to the bones that you want i.e. same bones as this part of the body) with the Limit Selection to Visible option disabled (on the horizontal menu bar) so that it paint the vertices you can't see.


POSER - Can Poser files be used in Blender and Blender in Poser?

Daz studio uses poser models and according to this answer exporting the model using collada (.dae) works, .fbx may also be a good option. You could export a posed character with .obj but that doesn't include the armature.

While each renderer can use the same image textures, expect some manual texture creating to use cycles, which is blender's newer and better render engine. You will probably find this much easier with the new principled shader in the new blender version about to be released. You can test it in the daily builds and see it in use in this tutorial

I would suggest asking/looking at poser specific sites like the daz3d forums which is where I first heard about blender years ago, people using it to make poser models.


Not really my area of expertise, but depending on what you want you could try baking a texture from a glossy sphere.

Create a new UV Sphere, you may want to make it an all quads mesh
first by removing the top and bottom vertex, then selecting the
first open edge loop, and extruding it, then scale it to zero so
that all vertex merge at the center, but don't remove doubles.
Mark a seam along one of its vertical loops and select one random
face. Now Unwrap it using the Active Quads option. In the image
editor it should wield a perfect orthogonal grid mesh.
You can now assign a perfectly glossy material to the sphere and use
it to bake an environment map of your island.

I have not tried it myself, but it should work; I used a similar technique under Cycles render to create a cube map environment


Is the add landscape button really just a pre-made Mt. McKinely?

You can change the settings for the ANT landscape creation by moving the random seed:

By the way ANT refers to Another Noise Tool


To elaborate on Joel's recommendation of using smoke sprites: I believe he is suggesting an instanced set of small face primitives positioned in a scattering at the surface of the water object. Vary the transparency, size, and the magnitude of a small animated shimmer movement so that each small face (sprite) has an additive motion overlaid onto the base water object(s) in the waterfall. Also assign material and texture from a collection of smoke pngs.

A key consideration is that these sprite elements should remain roughly normal to the camera view plane...not parallel to the water or its not really acting as a sprite just another texture-mapped animated object.

The cumulative effect of the instancing is to allow variability of the image, shimmer motion, size, position, and transparency while reducing discrete object definitions. The art is in making the sum of sprite variations appear like hydraulic effects such as turbulence!

(Note :if my 'comment all' creds came thru I would have simply commented on Joel's comment instead of adding a new 'answer' with these details.)


I am trying to animate an object with a very simple animation but it does not work

I think you accidently set your animation to constant interpolation(documentation).
You can make the cube move(not teleport) by setting interpolation by setting interpolation to linear or bezier. To set the interpolation, select the animation point or points(Diamond shape in timeline), press t and select linear or bezier.


Try this node setup. There are 3 components, the COLOR, the NORMAL, and the ROUGHNESS MASK. I show the whole setup in the first picture, and closeups of the node arrangements in the second and third. The last image is the final product.
The Breakdown is as follows

For the normal and roughness, I started with a scaled up musgrave texture to get a good small grainy look. However, this setup causes the unwanted effect of large dark blotches among the grain, so I copied the texture but increased the dimension which thankfully, provides only those big dark blotches. So, I subtracted the big blotches (top texture in graph) from the original musgrave image to leave me with just the grit. I also noticed while writing this that the colorramp I put In my graph was for my testing purposes only, and doesn't need to be there.
To compliment this texture arrangement, I slightly scaled down noise texture and used 2 different color ramps on the result. The ramp going to the ROUGHNESS, I clamped rather tightly, because I wanted blotches with sharp cutoffs (not as much greyscale) to use as part of the roughness mask. The other one I simply lightened the darks and darkened the lights slightly to soften the impact on the normal map. (These represent the big, not-shiny blotches you can see, but also warp the normal slightly - the road would  look too distorted  if I plugged it in at full strength)
I then mixed the two texture maps (the musgrave mix and the noise) to make a bump map that I could then use as the strength factor of a normal map. I also provided the color from the musgrave to the normalmap to help define the finer detail areas. For the roughness, I mixed the sharpened noise map with the musgrave mix (the musgrave doesn't need to be clamped like the noise - a smoother greyscale gradient helps simulate surface distortion caused by freshly fallen raindrops). I inverted this mix before using a roughness mask because for normals white represents high and black represents low, wheras for roughness white represents rough and black represents shiny. Usually you invert the roughness mask because "higher" areas of things are more prone to wear and therefore are first to become shiny (think of the dots on a basketball). To be honest, it doesn't matter as much here because all i'm defining is the difference between a wet ground and a "wetter" puddle. This arrangement happened to look the best.

For the color, my aim was simple, make 2 yellow lines and a dotted white line on a black background. The lines I was able to get by using a wave texture, scaling as needed until I had the right number of lines and mostly correct spacing - I further corrected the position and spacing  with the use of a texture coordinate node (typically use generated for procedural textures ) and a mapping node to be able to play with the positional values. To help with the line definition and colors I used color ramps, clamped rather tightly.
For the center line, It was simply a matter of making a solid white line in the center, and another wave texture with a bunch of dark lines. I rotated the bunch of white lines 90 degrees sideways using the mapping node, and then multiplied it with the solid line (with black and white, multiplication works because black areas stay black [anything multiplied by 0 stays 0], but white areas also get multiplied by 0 and therefore, subtracted].
I finally used a mix node to combine the color lines with the dotted white line.

Together, when all connected to the BSDF, they produce this result.

I hope this helps. Let me know what you think.
Cheers
EDIT - I have included the file of my setup here in case anyone wants to have a look. Just know, this is not meant to be perfect, just a quick, procedural rainy road. I'm sure many improvements can be made by playing with the values. I encourage you to experiment.
Link is here:
EDIT # 2 - So, I got fed up playing with the shader nodes... I think I've been at it too long. I'm much more familiar with Substance Designer's nodes, so I made this road material just for you. There is no need for any HDRI, scene lights will do just fine.
Files are here: https://drive.google.com/drive/folders/1v2_GDIgjTtdj6_2e22YH7535ZNPO9Wd2?usp=sharing
Here's how to connect them. Pay attention to a couple of things: First, the strength on the bump node, it's set to 0.1 on purpose - 1 is generally way too high. Also, the bright/contrast node is not necessary, however I put it there to be able to control the "darkness" of the road (level of white "stones"). Also, this will require unwrapped UV's, but since it's only a flat road you're making (a simple plane probably), this is well within the skill level of even the newest beginner. If you notice on the mapping node, I have the texture scaled 2x2. for the size of the plane I was using, this looked the best without showing any noticeable repeats. Adjust the scale as necessary to fit your project.

Lastly, if this material doesn't work for you (don't feel bad if it doesn't - it didn't take me that long ), you might be able to find others to your liking at free PBR material sites such as this one - https://3dtextures.me/
Best of luck with your video.
EDIT # 3 - MOVING THE RAIN
Ok, I posted a pic of how to achieve a pretty good approximation of the rain in motion. The secret is to add a VALUE node, but instead of choosing a number for the value, click on the field and type in #frame. This will cause the value to change with the frame as the animation plays. Connect this to the LOCATION input of separate mapping node connected only to the NORMAL MAP. However, the frame number in it's own it too high and would move the map too fast, so I myltiply it by something small (0.001) with a math node before connecting. When you hit play, the normal will be dragged diagonally across the x/y f the image. Try it out and see what I mean. Assuming you used the images I provided, the setup should look like this:


Hooking selected object to control point of Bezier curve via scripting

OK guys, I think I found the solution! Here: https://www.youtube.com/watch?v=ImWd1-FxhE4

In case the video becomes deleted in the future for some reason, here is the key to selecting the desired control point: (just an example)

bpy.data.curves['BezierCurve'].splines[0].bezier_points[0].select_control_point = True

So basically there is this boolean data member of the control points called select_control_point and you just have to set it to true.


Difference between compiled version and downloaded?

The main reasons to build blender yourself are:

If you build from the latest sources, you get the very newest features. You'll also get the latest bugs, so save early and often, and keep the bug tracker open ;)
You can apply patches such as this one, and get features which aren't even in the official sources yet.

There are also some hardware-specific optimization tricks you can do depending on your compiler, but these can potentially make blender unstable. Also see the wiki.


Smoke Sim rendering in Viewport but not in final render (2.8, Cycles)

save Project(if you don’t save the project the bake will not work)
select "Smoke Domain"
select "Physics menu"
select "Cache"
click on the Bake


Where is the Layers panel in Blender 2.8?

Blender 2.8 re-implements the scene layer system, as it had limitations. How it now works is explained here: Layers Manual and here: Blender Dev blog.

The scene layers are gone and their functionality was implemented in Collections (=groups) and View Layers.

Instead of sorting objects onto different scene layers, you can sort them into different Collections.

Add and Move between Collections with M
Link to Collection with Shift+M (so an object can be in multiple Collections)
Hide and Unhide Collections with CtrlH

Instead of using scene layers as masking layers in Render layers, now you can use Collections for masking or to effect only indirect rays (shadows and reflections):

View Layers are what you would call Render layers pre-2.8-Blender. Add them here:

A View Layer will remember your settings of objects and collections for visibility in view and render, selectability, holdout and indirect-only, etc. You find the settings for View Layers in the Properties panel:


Can I delete these past version folders in my user App data

Each of those folders is only required for that specific version of Blender.

You only need to keep the folders for any versions of Blender that you still use. So, for example, if you no longer use version 2.65, you can safely delete that folder, etc.


For precise scaling, consider using Orthographic View and grid snapping.

Enable View > Orthographic View (Numpad 5), and then choose one of views, Shortcut: ~
Enable Snapping > Increment, and check Absolute snap. This will ensure snapping to grid.
The grid will scale when you zoom in and out


Yes, you can add your color LUTs at the end of the existing color transforms chain to have a more accurate display.
You can add the color profile LUT to the folder where all of the other LUTs for blender are, or edit the config.ocio to look for the luts in an aditional folder.
Next, you need to create new definitions or stanzas in the config.ocio  file based on the existing ones and concatenate the LUTs at the end of the color transform chain.
Use the color corrected view transforms to work in blender, but know that you need disable them for the final output, as you don't want to bake your monitor's curves into the file.
Here's an example of an added lut the medium contrast Look to make things look blueish
Note the name change and how a lut called testlut is added at the end of the transforms chain.
- !<Look>
name: Medium Low Contrast BLueTest
process_space: Filmic Log
transform: !<GroupTransform>
    children:
        - !<FileTransform> {src: filmic_to_0-60_1-04.spi1d, interpolation: linear}
        - !<FileTransform> {src: filmic_to_0-70_1-03.spi1d, interpolation: linear, direction: inverse}
        - !<FileTransform> {src: testlut.cube, interpolation: linear}


Motion tracking : setting parameter for multiple selected trackers

I would advise you not to treat all trackers the same. Not all trackers need to be in a single mode, some work better with perspective, some with loc rot, some with loc rot scale. It all depends on the kind of motion you are tracking and how the particular tracked feature moves in the video and the item's visibility. If you are learning, think of trackers as individual processes. Supervise the behavior of each tracker individually to learn how to get more accurate results.

And to answer the question, no there is no easy way to select all trackers and change the motion model for multiple trackers. It could probably be done by scripting.


error passing a property to a function (name not defined)

ok, so...I just had to add self. before the property for the function to recognize it (and lose the .value, since it is a boolean, but that's a different error). Like so:
if self.only_active is True:
I still don't know how to get the active object. The whole context part is particularly confusing to me. But I guess I'll get it eventually.


Character rig not moving certain parts of mesh (Meta-Rig)

Yes, it's a weight problem: having the pad with the correct weight relatively to the arm bone is not enough: you have to remove its weights relatively to others bones (chest, head, shoulders).
Check theese answers for more infos:
How to make "Weight Paint" affect all vertices, even those with zero weight?
Add armor to the body without long weight paint


What's the best way to sculpt or texture without a drawing pad?

I think you need to get yourself a tablet if you feel you need one. There is nothing wrong with sculpting with a mouse only as well, it will be a different experience and it will tend to take longer because you cannot control the pressure, but you can draw a couple of weaker strokes on top of each other so it's kind of similar to one stoke that is stronger in some parts. If you practice more you will get more efficient at it. It is generally easier and faster to sculpt and draw with a tablet. If you just got one and it feels terribly uncomfortable to use it, don't worry, that is natural, you need time to get used to a tablet once you start using it. The unnatural feeling should go away in a few months of using it.


You probably didn't turn off Ambient Occlusion in the Scene context menu. Do that (and only that) and you get this:

Also, if you change the background color to black (AFTER turning off Ambient Occlusion in the Scene context menu), the entire scene will be black (which will not happen when it is on). This signals that changing the background color will now affect ambient lighting


Why is the volume scatter more dense in the viewport than in my final render?

You can try setup like below.

Then adjust "density" and mix shader fac.
Then what You also can do is to power up your lights.


Is there anyway to snap to vertices while using Edge Slide with Clamp Off?

I know this is an old question, but I've been having the same issue and managed to figure it out:

In Edit Mode, select an edge or a face that you want to use as a custom transform, this works also in object mode for objects.
Press Shift +  Numpad 7, this will align the view to selected in orthographic view.
Press Ctrl + Alt + Space bar, in order to create a custom transform.
In the Tool Shelf, that you can toggle it using T, under Create Orientation, at the bottom of the Tool Shelf, make sure you check Use View, this will align the new custom orientation to the view.
You can also rename the custom orientation to something meaningful. You can delete it or change it's name in the Properties Panel N.
Now you can use the new custom orientation instead of the default orientation, such as Global or Normal..etc. Don't use slide because it will still not react to snap, instead use transforms to move G, rotate R or scale S using the new custom transform, you can still lock axis and toggle between Global and custom transform using shortcuts.
Check Blender Documentation on Custom Orientations:
https://docs.blender.org/manual/en/dev/editors/3dview/object/editing/transform/control/orientations.html#custom-orientations


Using Cell Fracture the object that is supposed to break, explodes or breaks before impact

The Cell Fracture and physics process by default start at frame 1, and that has to be delayed.  After you do the fracture, select all segments and press  Ctrl + L  to link them all. Choose Animation data.
Now what you keyframe on one will affect them all.  Select one segment, set and keyframe it's physics to Animated at frame 1. Untick and keyframe the Dynamic box also.
Move the timeline to the collision frame (or there-abouts) and keyframe the boxes in reverse.  Animated unticked and Dynamic ticked.
Addendum 1st April 2021

One thing further to the above.  If the physics are still activating at frame 1, save the file and exit Blender.  Reload it.  This will clear the physics cache.

Apparently the procedure has been changed in vers 2.8+ and the new method is set out here -
linking objects in blender 2.8


Well... Now I am really showing my ignorance about Blender. Last night I tried everything I could think of. I clicked on anything and everything that looked like it might be the right thing to change it back, and found nothing. But as I was making a screenshot, I saw a button I didn't see last night (my vision is clearer this morning) and I don't remember what the label said exactly, but "previous" was part of it, so I clicked on it and it changed it back to the model I had been trying to export last night.

But it's Murphy's Law of Seeking Help... As soon as you ask for help, you figure it out yourself!

Thanks anyway...


How to start modeling a square metal profile with holes?

You can start considering the object symmetries, 8 parts like that:

Thus, we'll try to make it and use Blender's mirror modifier.

As rounded parts are generally more complex to do, we start with them:

Add a circle, with a relative low resolution (say 16 vertices). This will be the center of the shape.

Then duplicate it in edit mode ShiftD and extrude and scale this last one ES to the wanted value.

Here you should have something like this:

As this is symmetrical, from the above picture, we can delete the unwanted part. So, only keep this:

From that, it is only aligning and extruding to be at the dimensions you want:

Now the mirror modifier part:

We need two mirrors,

One to make a quarter of the shape: it uses an empty as pivot rotated 45 degrees.
One to replicate the previous one along X and Y axis.

Here is the setting:

So we now have:

Finally, we can add a solidify modifier to extrude the shape:

Last points:

Use shade smooth (in object mode W then 'shade smooth')
And use autosmooth for the normals (look at the image below)

A blend file with the several steps included:


Iterate over custom properties without searching?

It is correct that accessing values by key using .get() on bpy.types.struct iterates through the elements. The function that gets called through the Python API is pyrna_struct_get() (bpy_rna.c). It uses IDP_GetPropertyFromGroup() (idprop.c) which in turn calls BLI_findstring(listbase.c). As the name already suggests it performs string comparisons by iterating through a list.

It should be avoided iterating over the keys and then accessing the values, both in Blender and also Python software that uses actual dictionaries as data structure. As batFINGER suggested you could use a.items() instead.

for key, value in a.items():
    # do something with either key or value
    pass


Rendering scene background in only some frames of an animation

You can animate the renderability of the objects that are "background", pressing "I" while hoovering on the camera icon of an object or an entire collection.


How can I export an animation to be viewed in 3D

In the Properties Panel > Scene Context > Views Tab activate Views and Stereo 3D

Select your camera and in the Properties Panel > Camera Context > Stereoscopy Tab select Off-Axis. Set Convergence Plane Distance to the distance the viewer is seated from the Television. Set Interocular Distance to the space between the viewers pupils, usually 7 - 10 cm.

Go to the Properties Tab of the 3D Viewport and find the Stereoscopy section. Select 3D, and check Cameras, Plane and Volume to see the layout of the 3D camera in the viewport.

Make sure your animated and still objects are behind the (Convergence) Plane in general. If they're supposed to come in front of the TV, they have to come in front of the convergence plane. This effect does rarely work well on most television sets and should be avoided. You may need to adjust the scaling of your scene. Since the Interocular Distance is set in centimetres in the Viewport, the 3D props should have the correct scale.

Render your scene. Two image sequences will be created. One with the left camera suffix "_L" and one with the right camera suffix "_R". To separate them, so Blender can read them easier, open up the directory with the sequences. Filter search by "_L". Select the left image sequence files and move them to another directory.

To join both sequences into one movie, there can be many layouts, I will describe the side by side layout.

Set the scenes width to twice the width of your image sequences.

Open the Video Sequence Editor and add the left image sequence. In the VSE, check Image Offset under Strip Input.
Add the right image sequence above the left strip. Check Image Offset under Strip Input and set the X values to the width of your images. Set the Blend mode to Alpha Over.

You will have both sequences side by side next to each other. Render as a movie format accepted by your television.
Playback the movie file on your television set. Press the 3D button on your remote and cycle through the modes untill you reach 3D side by side with both images next to each other. The television will then adjust the image automatically.


If the rings on the top and bottom have the same number of vertices, you can select the top and bottom edges, then press the space bar and type bridge edge loops:


Blender resets restricted rendering settings upon frame change

I have been able to come up with a workaround for both my questions.
It is possible to remove desired particle species for all frames of the render by setting their radius ('scale factor') to 0 in the 'Molecule' section of the Cellblender add-on. They will therefore still be turned on for the render, but invisible due to zero volume.

This enables to not just render one or multiple images, but also an whole animation. Then it is possible to extract all single frames of that animation either from the temporary directory by hand or by choosing 'save all images' of the render window.


How to keep z axis aligned vertically while rotating camera angle

You can simply lock the Y axis of the camera rotation.

Here:

Or here:


Saving rendered image into a file doesn't work

You have to actually render your image first before you can save your render as a file. To do that press F12 while your cursor is over your 3D View window.

Wait for the render to finish and only after that with the mouse cursor hovering the rendered image can you press F3 to save it. Alternatively if the hotkey for some reason is not working you can save your render by going to the Image Menu > Save Image As, by default at the bottom of the UV Image  Window

Are you using a laptop computer by any chance? Some computers by default use the function keys F1  to F12 as direct shortcut keys for Microsoft Office or other Microsoft applications, and to use them as regular F keys you have to press the Fn button on your keyboard.


You have to use the volumetrics input in the material output node, instead of the surface input.

There are three different volume shaders. Volume absorption, volume scatter, and emission (yes, the same node used for making physical lamps).

Volume absorption is for simulating how light seems to vanish, like in smoke or clouds.
Volume scatter is for simulating how light bounces around inside of an object, similar to subsurface scattering.
And emission, when plugged into volume, is useful for rendering objects that emit light and are visible to your camera. This is good for flames and glowing objects that are semi-transparent.

(More info here)


Once you've symmetrized, you have all the symmetrize options in the Operator box on the bottom left of the 3D View, and you can choose +X to -X.


In edit mode, select every face below the collar that you want to flip and press W > Flip Normals.


Single image texture is not rendering correctly

Oh I found it! It was because I was applying a Subdivision Surface Modifier to the render, but not in the preview


You don't need to parent the Particles to the Metaball.
You want the particles to become metaballs. you achieve this by changing the rendering object of the Particle system. In your screenshot the particles are set to "halo". Go to the Render-Section of your particle system and change that to "object" (yellow rectangle) and select your metaball. The particles themselves are now metaballs and can interact with each other.


problems of keeping armature after put dynotopo on in sculpting mode

Dyntopo messes with vertex groups, and the weights attached to an armature are vertex groups. That means that if you want to sculpt an object that is being posed by an armature, you have two options: either don't use Dyntopo or apply the armature modifier. The latter option is only a good one if you don't plan on changing the pose; if you choose that option, I'd first make a copy of your current object that you can revert to if you change your mind. The other option would be to leave Dyntopo off, and just use subdivisions instead, as long as you're not planning on sculpting small details. In fact, if all you want to do is smooth out the joints, for example, just adding a Subsurf modifier after the armature modifier might do the trick with no sculpting required.


Edited texture not replacing old texture in render

No programming required to paint in blender. :)

It looks to me like you simply did not save your image after you painted it.

Blender will display the changed image in the viewport, but until you save it blender will not render it (and your work will be lost if you close blender, even after CtrlS).

With the mouse in the UV/Image Editor press AltS, or from the header Image > Save Image. That writes the changes you made in blender to an image file, actually saving your image. Now your render will look as excepted.

Here is an animated gif showing me painting on an object in the 3D view, then rendering it without saving the edited image.


Is it possible to select all connected or unconnected nodes?

You can use Select Linked To Shift+L and Select Linked From L repeatedly till you have all connected nodes selected. Then you can Inverse selection Ctrl+I to select the unlinked nodes.

Alternatively you can use the following script that will add a Select > Select Linked menu option.

from itertools import chain
import bpy

def get_linked(node, processed=None):
    if processed is None:
        processed = []
    processed.append(node)
    for socket in chain(node.inputs, node.outputs):
        for link in socket.links:
            target = link.from_node if node == link.to_node else link.to_node
            if target not in processed:
                get_linked(target, processed)
    return processed

class NODE_OT_SelectLinked(bpy.types.Operator):
    bl_description="Select all nodes linked to the active node"
    bl_idname = "node.select_linked"
    bl_label = "Select Linked Nodes"
    bl_options = {"REGISTER", "UNDO"}

    @classmethod
    def poll(cls, context):
        return context.active_node

    def execute(self, context):
        for node in get_linked(context.active_node):
            node.select = True
        return {"FINISHED"}

def menu(self, context):
    self.layout.operator("node.select_linked", text="Select Linked")

def register():
    bpy.utils.register_class(NODE_OT_SelectLinked)
    bpy.types.NODE_MT_select.append(menu)

def unregister():
    bpy.utils.unregister_class(NODE_OT_SelectLinked)
    bpy.types.NODE_MT_select.remove(menu)

register()

To auto load: save the above in scripts/startup/ with a .py file extension.


Does anyone know how to make a procedural random tile texture?

to achieve such a goal you have to split the question to smaller sub steps, for example:

Split a UV (or XY) coordinate to a grid by using the Fraction or Modulo Operator.
Modify each grid cell local UV with a random translation

To gain randomness there are some mathematical combinations that generate pseudo random behavior, but each input will always generate the same output. Therefore i convert a common shader function to a node group:

float N21(in vec2 p) {
    vec3 p3 = fract(vec3(p.xyx) * .1031);
    p3 += dot(p3, p3.yzx + 33.33);
    return fract((p3.x + p3.y) * p3.z);
}

Calculate the distance to the border of the modified cell to create a "mortar-mask"
Combine each cell by calculating "which cell is at this pixel" by using Greater or Less than, Multiply or Adding Values. It often helps by keeping all values in a 0 to 1 range.

In the end you get different masks and UV coordinates which can be colorized with normal image textures to get the marble look.
It may help to use a tool like Shadertoy (Example of my wall texture algorithm) to test a algorithm and convert it to node groups after you are satisfied with the result.
You could use my blend file as a library to link or attach the node groups. Try to modify some values to see the result.
Getting good looking procedural textures is heavy math!
Have fun and greetings from Germany!


Having issues with Low Poly Texture Colours

you probably have too high the specularity of the material, what I'm showing you is an example in blender render, I'm not a render professional, my area is programming, but I've been studying for almost 4 years and today I work with shading language, and I'm still using BGE.

in conclusion you have to lower the specularity of the material so that it does not seem like it is going beyond the spaces of your color palette

I made my palette with 128 X 128 px squares
use unwrap view project, with the View Ortho 1
from the leaves of the trees select some faces from my unwrap and place them in another color to contrast

if you need to expand this answer, just say uqe more you want to know to include it in the answer


Select > Mirror Selection
but this only works if your model is symmetrical
otherwise I don't know an easy way to repeat same size selection


How do I save a certain workspace as the default workspace (not default upon opening blender)

Any changes you make to any of the workspaces can be saved as part of your Startup File.
Here's my Compositing screen, I also enabled the denoising data passes so I could denoise renders by default.

Just open a new file, make any changes, and go to this menu.  Whatever workspace you're currently in will be the one Blender opens to.


Texturing various questions questions - Cycles

1) The term you are thinking of is "texture seam". Generally, if you have one flat side of an object, you would try to unwrap and texture it to avoid seams. it might be that the texture you are using isn't suited to what you have.

2) I quite favor using micro-displacement for close-up images that require a lot of detail. However, if you are not going to be quite close to your object, it is possibly better for you to use normal/bump mapping. It is far less computer intensive than displacement/subdivision.

3) Yes, you can reuse assets and textures. Taking your wooden beam example, you might find that creating only three different beams, and using these in your scene gives enough variation. There is a trade-off between saving time/effort and avoiding repetitive items and textures.


Equivalent of UV Squares in 2.8 to make islands straight?

Why not use UV Squares? I got it working in 2.8.

https://blenderartists.org/t/addon-uvsquares-v1-4-updated-any-shape-supported/613111/99


You can select all your vertices, go in the header menu > Select > Checker Deselect:

Then you can change the options in the Operator box, and delete with X > Dissolve Vertices:


It's not clear what you did and what you are trying to achieve, so here is my best try:

If you want to render single image, you can press F12 (Top menu:Render>Render image). Then your image is displayed in Blender Render window. You can save this image by pressing Shift+S (Top menu: Image>Save as). Then you can choose filename and file type.

If you want to render image sequence, you have to go to output panel (usually located at bottom right of the screen (or right panel if you are using Rendering layout), its card has printer icon). Choose resolution, directory which should contain resulting files and file type (for example PNG). Then hit Ctrl+F12 (Top menu:Render>Render Animation). Images should appear in directory you choose, no other action is required.

If you want to render video file, you can do it similarly to prevous steps, but instead of choosing image type such as PNG, choose FFmpeg video and specify details in Encoding section. Again, after pressing Ctrl+F12, resulting file will show up in directory you have choosen in Output card.

If you render bigger project, it's good idea to render to images in case something breaks during render, or you realize you want to change something and re-render some images. If you want to make single video from image sequence, open new Blender file using File>New>Video Editing. Hover mouse over Video Sequencer and press Shift+A. Click Image/Sequence. Go to directory where you stored your image sequence, select all images (A) and press Add Image Strip. Choose render-resolution and frame-rate and render in a same way as I described above.

Pressing Ctrl+S (File>Save) or Shift+Ctrl+S (File>Save as) is reserved only for saving .blend file.


How to apply existing facial blend shapes to beard

Difficult to be specific without knowing the detail, but I'd try creating shape keys for the beard to match the shape-keyed movements of the face then, when you're finally setting up controls, link them so you run face and beard drivers simultaneously. Obviously this won't help a lot if you're after a big bushy beard that has a lot of follow-through (that'll mean a bit of extra tweaking).


I think I found my answer, I need to enable view in render, under display, in the onion skinning tab in object data properties


setting an objects origin to match its face normals

Quite a few possible ways.. here's one:

Select a face of the object, whose normal you want to be Object Z, and in the Header > Transform Orientations dropdown, hit the little '+' to create a Custom Orientation from it.
In the Object Mode Header > Options menu, check 'Origins' (version 2.81+)
With the object (and therefore its axis) selected, Header > Object > Transform > Align to Transform Orientation, selecting the orientation you have just created, from the dropdown in the 'Adjust Last Operation' Panel.

(and don't forget to switch the 'Origins' option off again ;) )
You can actually create a Custom Orientation from any 3 vertices. Or determine Y down an edge, or from any 2 vertices. In both of those cases, though, you might be 180 degrees out; the selection is not ordered.


Create an outline mesh around another structure / edges with equal distance

Considering the base shape has no surface and is edges only, you can convert it to a curve with AltC, then use the "extrude" parameter:

Doing that the distance from the outer edges to the base vertices is constant.

Edit: in meantime I've downloaded your file. From both solution the problem is your shape is scaled. So you need to apply scale CtrlA before any other thing.


For example, using the bpy docs, see the base classes (names of the valid socket ID names).

import bpy
import random

max_number = 5
nodes = []
with_fade_out = 2

try:
    tree = bpy.context.scene.node_tree
except:
    bpy.context.scene.use_nodes = True

group = bpy.data.node_groups.new(type="CompositorNodeTree", name="MultipleSwitch")
group.inputs.new("NodeSocketRGBA", "Default Image")

for i in range(0,max_number):
    group.inputs.new("NodeSocketRGBA", ("Variation - " + str(i+1)))

input_node = group.nodes.new("NodeGroupInput")
input_node.location = (-150, 0)

socket_list = [
    'NodeSocketBool', 'NodeSocketColor', 'NodeSocketFloat',
    'NodeSocketFloatAngle', 'NodeSocketFloatFactor', 'NodeSocketFloatPercentage',
    'NodeSocketFloatTime', 'NodeSocketFloatUnsigned', 'NodeSocketInt',
    'NodeSocketIntFactor', 'NodeSocketIntPercentage', 'NodeSocketIntUnsigned',
    'NodeSocketShader', 'NodeSocketString', 'NodeSocketVector',
    'NodeSocketVectorAcceleration', 'NodeSocketVectorDirection',
    'NodeSocketVectorEuler', 'NodeSocketVectorTranslation', 'NodeSocketVectorVelocity',
    'NodeSocketVectorXYZ', 'NodeSocketVirtual']

for s in socket_list:
    group.outputs.new(s, "Out " + s)

output_node = group.nodes.new("NodeGroupOutput")
output_node.location = (max_number*100 + 100, 0)
group_node = tree.nodes.new("CompositorNodeGroup")
group_node.node_tree = group

you can see here that of all those NodeSocket types, the main ones are:

NodeSocketBool
NodeSocketColor
NodeSocketFloat
NodeSocketInt
NodeSocketShader
NodeSocketString
NodeSocketVector


You can join multiple bones together. You will need to flip one of the bones around (AltF) so that there is a bone tail in the correct spot. Then just set the other two bones' parent to the flipped bone; and enable Connected.


How to accurately recreate a circular design for 3D print?

Blender was never meant for precision work.
One way to get similar results is to use arrays.

Start with proper sized small segments. Add curve + array modifier arround its circle part,

For circumference extrusions it's similar. Use 'object offset' setting in an array modifier.

blend file


How to get RGB values for a portion of texture, specifically an image

If you're just trying to extrude a silhouette of an object, doing it with a subdivided plane is probably the worst option (you'll end up with potentially useless geometry, I'm assuming this isn't what you want).

Your best bet here is probably to import the image as a background image through this interface in the right panel.

Then go into an orthographic camera mode and create geometry over it.

Another option could be to open the picture in a program like Adobe Illustrator, automatically or manually trace it to create a path, export as SVG and import to use as geometry in Blender.


how to generate more "gusts" of wind with the wind force field?

Maybe you've already thought about that but you could simply keyframe the Strength value of your wind, going, for example, from 100 to 1000 or whatever, then use the NLA to repeat this as a cycle. It looks like creating a Noise modifier in the Graph Editor doesn't have any influence though...


Why is my texture distorted after using Smart UV unwrap?

Either the above or make sure to hit ctrl+a and set all transforms. I have learned that is a lot of my issues with almost anything including UV mapping.


Will Blender support design and dimensioning machine drawings?

While blender is more adapted to creative modeling than technical or precision modeling you can create mechanical models and use them to create good looking blueprints.

In this youtube tutorial, the measrueit addon (included with 2.78 or can be manually installed on older versions) is used to create the measurement lines. The lines and annotations don't show in a normal render, but the addon provides a way to create a render with measurements.

Freestyle can also be used to create outlines for blueprints. This blendertuts tutorial explains how to define solid and dashed linestyles to get a hidden edge blueprint result. It is also possible to get more of a hand sketched result.

The CGCookie archives also has an old tutorial that manually creates text objects and lines to get the following blueprint.


The symmetrize will use the armature's origin as the axis center, to fix your problem you could for example align the armature's origin to the dog's origin:

Make sure that dog's origin is centered to its geometry (Object > Set Origin > Origin To Geometry).
Select the dog object.
ShiftS > Cursor To Selected.
Select the armature object.
Object > Set Origin > Origin To 3D Cursor.
Go in Edit mode, symmetrize again.


How to add images from selected folder via Python

You can add an adapted version of this nice generator to your code to find all images in a given folder (such as the ones you keep in your Scene.path property):

import bpy, os
def path_iterator(folder_path):
    for fp in os.listdir(folder_path):
        if fp.endswith( tuple( bpy.path.extensions_image ) ):
            yield fp

Then you can iterate over the images and do whatever you want with them, for instance to add them to the list of images blender can use for textures and other purposes:

for imgPath in path_iterator( bpy.context.scene.path ):
    fullPath = os.path.join( bpy.context.scene.path, imgPath )
    bpy.ops.image.open( filepath = fullPath )


If you are using 2.8, I found that the principled shader is very easy to set up for this provided you make use of an environment texture in the world shader.


How to add imperfections to the Principled BSDF Shader (Cycles)?

Just add mix rgb (screen) node to your roughnes map and connect surface imperfection map to the second socket


Animation Nodes: add a new shape, like UV sphere

As the name says Animation Nodes it is mainly made for animations, so there are few mesh generators than sverchok.You can always create an uv sphere in blender and insert it in AN by the mesh or object nodes input.


A screenshot will help to give a clear answer!

Try going to object mode again and going to edit mode. if you are not able to select the vertices or faces means that the object is a different from what you are trying to edit.


You can enable drawing guides and snapping in the Speed Guides Menu.

Check the small icon to enable it
Select the type of guides
Enable snapping and adjust the snapping grid size

You can also enable overlay grid in Viewport Overlay > Canvas and change it's appearance in Viewport Display > Canvas

Further reading in Blender Manual:

Introduction to drawing
Draw Guides
Drawing Planes


How to make a bronze material in Cycles?

Here's what I came up with using procedural textures:

I would use dirty vertex colors in 3D view > header > Paint while in Vertex paint mode to add some dirt to the corners:

You can then use this in your node setup via an Attribute node, with the name set to the name of the vertex color layer (Col by default):

You could more than likely get a better result more easily by using image textures.

I'd also recommend this tutorial, which has some great examples (and a free image texture).


Retopology Newby - Used Shrinkwrap Modifier - Whats next?

Retopology reduces the geometry of the mesh to a lower-poly state. You've done that, which is already a huge step. This will decrease render times.

As you've surely noticed you've lost some detail during the retopology process, and that is a shame - but luckily there is a way to get around that: Baking a normal map. This will allow you to add the additional, fine detail in the material which will be vastly more efficient to render compared to the high-poly version of the mesh. This does require your low-poly mesh to be UV unwrapped - this tells blender how an image will fit on the model.

As a first step you want to move the models into each other - so that they occupy the same space (overlap, essentially). After that go to the UV/Image Editor and create a new image (Select Image -> New in the top bar). Select an image resolution. Set the background color to black and generate it.

After that you want to make sure that you're in cycles, and under render settings find the "Bake" option. Click the "Selected to Active" checkbox. Set the Bake Type to Normal.

Select your high-poly mesh, after that select your low-poly mesh while holding Shift.

Finally we need to tell blender where to bake the image to. To do this go to the material node editor and add an image texture node. Once it's been added select your image in the drop down menu. Select the node as well, and then hit the bake button. Yes, this is a somewhat confusing workflow.

Once you've hit bake you should see an updated normal map. If you get some weird green spots in your normal map you want to go and increase the "Ray Distance" setting in the render options.

If you want to see the workflow rather than read it I'd recommend this youtube video right here


I created a rough remake of your shape

Start by adding a loop cut as shown

Add another loop cut here

The SubSurf modifier will work much better now


If you are talking about these icons:

You need to change the Themes>User Interface>Tab Inner, Selected and Outline colors.

Edit: OK, you mean these:

Unfortunately, those are built from source. See this link if you are interested in trying to modify them.

You can change the background and border though by going to User Preferences>Themes>User Interface>Tool and changing the Outline and Inner Options.


I have the same problem, the the 2.83 Windows installer is asking if I want to CHANGE, REPAIR or REMOVE Blender.


How to split one control end of bezier curve

I think you can create such shapes only by combining 2 or multiple curves, because

  Each new segment is added to one end of the curve. A new segment will
  only be added if a single vertex, or handle, at one end of the curve
  is selected.

wiki page

The same may be applied to creating 'P' shape, thus joining 2 curve segments - it'll raise an error "Cannot make segment". You can duplicate that curve segment and place it atop of existing one, but still it'd be 2 different curves (example below).

As another way you may want to use simple mesh with all vertices deleted except for one. You then extrude shape needed either with E or Ctrl + LMB:

After adding mirror modifier you'll get that 'Y' shape. If you convert now this mesh into curve with Alt+C you'll see that it actually consists of 2 curves:

It's just the same what you would get if extruding this shape with curves manually.


If you are using Cycles render engine you could probably achieve a simplistic setup quickly using a mix between a diffuse and a translucent shader node. A voronoi texture for displacement or bump could help with the rough surface.

My diffuse color was setup for a quick random colors for display purposes, but you can use any solid color instead by removing the ColorRamp node and the Object Info radom output


You can try using the "displacement" node, check screenshot below.
Please keep in mind that you'll need a mesh with many faces to see any results.

Feel free to share your original file here if this answer is not helping you:
https://blend-exchange.giantcowfilms.com/


I'm not quite sure if this will work but it's worth a shot...
In Unity, delete all the materials except the one you want to use with the texture atlas. Make sure the texture for that material is actually your texture atlas. You will then notice that the mesh render's on most of the objects in Unity will look like the following:

All you should have to do is drag the same material that your texture atlas is on, onto that slot. Make sure to do that with all of your objects selected so you can do that all at once.


I'm not sure if I got what you ask but it seems that your rectangular mesh outlined in green has its local axes not aligned to its vertical/horizontal ides (probably you applied its rotation for some reason), and now you wish to make your local axes "realigned" in order to be able to "move" the mesh along one of those axes.

If you need this, you have to help your "axes realignment" with a separate object, say an empty.

you add an empty
you place it on one of your mesh "corners" helping with snap tools
you also use snap tools to rotate the empty, aligning one of its axes to one of your mesh sides
then you copy the empty rotation value (eg: 138.516796°)
then you rotate the mesh of a value of "180° - 138.516796°"
now your mesh is perfectly aligned with the grid, so you apply this new mesh rotation, which gets you good "local" axes
then you rotate "back" your mesh of the same amount but inversed ("138.516796° - 180°" => note, in the animation below I did this wrong), to rotate back the mesh where it was at the beginning (but now you have aligned local axes)
then you can move your mesh along the desired direction

See how it works:

Hth


Getting a flat, thin, long, cube (ribbon) to follow Beizer curve?

I would make the curve flat by not bending a mesh to fit it, but "beveling" the curve (adding thickness).

Add a BezierCircle (in addition to the curve you already have)
In edit mode convert the handle type to Vector (super quick way V,V), that will make it a square.
Rotate it 45° along the Z axis (just to make it straight along an axis).
Scale the square along the X axis, to make it a thin ribbon.
(Last step) On your other curve object set the Bevel Object to be the "BezierCircle" you added in step one.


Another way to complete operation: hit the Space bar, start typing "skin resize"

Change your hotkey: in the User Preferences window, in the "Input" section, you can search for "skin resize" when searching by Name, that will let you assign a new (or old) keyboard shortcut for that operation.

To find what you've got assigned to Ctrl-A, search by Key Binding and type "Ctrl A", that will show everything that's bound to that combination.


Is there a node that changes value based on ray brightness?

You set the physical properties of a material(s) and let the engine figure out how it effects light which when hitting camera creates the image. Not the other way around - how light affects material - that would mean that material could change (from metal to glass for example) under a light source.

The tail-light cover is made from glass, so for start use a glass shader with a light red color and a warm light source behind.

By modelling the glass thickness, you influence the travel distance of rays through the glass - the more distance the darker and more red the ray will be. The problem is that the default glass shader doesn't behave this way and doesn't absorb the light intensity while it travels through the glass volume.

For this you need to use a volumetric absorption shader with the glass.

PS. There are ways to cheat and actually use materials that magically change etc. but the volumetric solution is the best. You can study the fake absorption shader lineked above and how it does it with Light Path Node.


A problem with Blender's Bridge Edge Loops system

I don't think Blender's current Bridge Tool will give you quite the level of control you want.

In this case I would use a Curve object, but I realize that that's a bit of a change from the work-flow you have in Maya. A script can be written to prepare a curve object using the median and normal of two arbitrarily angled polygons, then all you do is tweak the width of the curve, the number of subdivisions ( or custom profile shape ), and convert to mesh, and join into the current mesh.

In essence it would be doing this under the hood, when you use a Curve you can manipulate the handles and even scale the start or end point of the Curve so it tapers.

here with tapering, each bezier_point has a radius property, this can be scripted or modified via the interface when you have a bezier_point selected

Given this proposal I imagine the following parameters as part of an operator.

tightness begin / end ( how long the curve handle extends from the median of each polygon )
attempt to scale begin and end profile to the two polygons that we used as a starting point

This would be a first draft of such an addon, I imagine much could be improved, but I think curves are the answer and not the Bridge Tool.

Edit

currently the repository has

a simple raw_script.py which can be used if you select two polygons. This is the 'minimum viable implementation'.
also a folder called 'tubetool' which is some boilerplate around the initial script so it gets an operator class, and can be installed as an addon (if you know how to install addons..)

Tool and Addon development will happen on GitHub, any input appreciated.
https://github.com/zeffii/TubeTool/issues/1


How to make a reflective object have a solid texture in Blender internal?

You'll want to experiment with the Influence settings of your texture. If you set your image to influence "Intensity" in the "Specular" section it will change the brightness of the specular highlight, keeping it from being washed out. NOTE: You'll have to turn off it's influence of other factors.

If your image is in color, it might not affect the specular intensity the way you want, by default. You may have to create a B&W version of the image that controls where the specular is brightest (white) and where the specular is dimmest (black), and then use the color version to influence the surface color. If you're up for a challenge, you can actually make a B&W version of your color image just using the texture settings in Blender. That way, you don't have two images to update when you make changes.

Depending on how sophisticated you want to get, you can also have another B&W version that's slightly different for controlling the hardness, another for controlling the specular color, and another for mirror.

I hope that helps!


From what I can find, that graphics card doesn't support CUDA or OpenGl... When you start Blender, does the Command Prompt display something like:

Buggy display driver! Disabling OpenCL!

If so, there is really nothing you can do.


How to control spacing/alignment of Label + Horizontal Enum Property?

Just set layout.use_property_split property in your draw method to True:
def draw(self, context):
    layout = self.layout
    layout.use_property_split = True
    layout.use_property_decorate = False  # No animation.
    ...

Custom Panel
Example based on the add-on template from: How to create a custom UI?

bl_info = {
    "name": "Add-on Template",
    "description": "",
    "author": "p2or, brockmann",
    "version": (0, 0, 3),
    "blender": (2, 80, 0),
    "location": "3D View > Tools",
    "warning": "", # used for warning icon and text in addons panel
    "wiki_url": "",
    "tracker_url": "",
    "category": "Development"
}

import bpy

from bpy.props import (StringProperty,
                       BoolProperty,
                       IntProperty,
                       FloatProperty,
                       FloatVectorProperty,
                       EnumProperty,
                       PointerProperty,
                       )
from bpy.types import (Panel,
                       Menu,
                       Operator,
                       PropertyGroup,
                       )

# ------------------------------------------------------------------------
#    Scene Properties
# ------------------------------------------------------------------------

class MyProperties(PropertyGroup):

    my_bool: BoolProperty(
        name="Enable or Disable",
        description="A bool property",
        default = False
        )

    my_int: IntProperty(
        name = "Int Value",
        description="A integer property",
        default = 23,
        min = 10,
        max = 100
        )

    my_float: FloatProperty(
        name = "Float Value",
        description = "A float property",
        default = 23.7,
        min = 0.01,
        max = 30.0
        )

    my_float_vector: FloatVectorProperty(
        name = "Float Vector Value",
        description="Something",
        default=(0.0, 0.0, 0.0),
        min= 0.0, # float
        max = 0.1
    )

    my_string: StringProperty(
        name="User Input",
        description=":",
        default="",
        maxlen=1024,
        )

    my_path: StringProperty(
        name = "Directory",
        description="Choose a directory:",
        default="",
        maxlen=1024,
        subtype='DIR_PATH'
        )

    my_enum: EnumProperty(
        name="Dropdown:",
        description="Apply Data to attribute.",
        items=[ ('OP1', "Option 1", ""),
                ('OP2', "Option 2", ""),
               ]
        )

# ------------------------------------------------------------------------
#    Panel in Object Mode
# ------------------------------------------------------------------------

class OBJECT_PT_CustomPanel(Panel):
    bl_label = "My Panel"
    bl_idname = "OBJECT_PT_custom_panel"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = "Tools"
    bl_context = "objectmode"

    @classmethod
    def poll(self,context):
        return context.object is not None

    def draw(self, context):
        layout = self.layout
        layout.use_property_split = True
        layout.use_property_decorate = False  # No animation.

        scene = context.scene
        mytool = scene.my_tool

        layout.prop(mytool, "my_bool")
        layout.prop(mytool, "my_enum", expand=True)
        layout.prop(mytool, "my_int")
        layout.prop(mytool, "my_float")
        layout.prop(mytool, "my_float_vector")
        layout.prop(mytool, "my_string")
        layout.prop(mytool, "my_path")

# ------------------------------------------------------------------------
#    Registration
# ------------------------------------------------------------------------

classes = (
    MyProperties,
    OBJECT_PT_CustomPanel
)

def register():
    from bpy.utils import register_class
    for cls in classes:
        register_class(cls)

    bpy.types.Scene.my_tool = PointerProperty(type=MyProperties)

def unregister():
    from bpy.utils import unregister_class
    for cls in reversed(classes):
        unregister_class(cls)
    del bpy.types.Scene.my_tool

if __name__ == "__main__":
    register()

Custom Operator
It's basically the same for the redo panel, you would have to create an extra row though:

import bpy

class SimpleOperator(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "object.simple_operator"
    bl_label = "Simple Object Operator"
    bl_options = {'REGISTER', 'UNDO'}

    my_enum: bpy.props.EnumProperty(
        name="Dropdown:",
        description="Apply Data to attribute.",
        items=[ ('OP1', "Option 1", ""),
                ('OP2', "Option 2", "")])

    my_float: bpy.props.FloatProperty(
        name = "Float Value",
        description = "A float property",
        default = 23.7,
        min = 0.01,
        max = 30.0)

    @classmethod
    def poll(cls, context):
        return context.active_object is not None

    def execute(self, context):
        print(self.bl_idname)
        return {'FINISHED'}

    def draw(self, context):
        layout = self.layout
        layout.use_property_split = True
        layout.use_property_decorate = False  # No animation.

        row = layout.row(align=True)
        row.prop(self, "my_enum", expand=True)
        layout.prop(self, "my_float")

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

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

if __name__ == "__main__":
    register()

    # test call
    #bpy.ops.object.simple_operator()


Can't apply modifiers with shapekeys on blender 2.8

Lets say we have a mesh with 2 shapekeys: 1 basis and 2nd Big Ears.

Create a copy of the mesh, select the copy and delete the basis shape key, then the big ears shape key.

Select the original and delete the big ears shape key, then the basis; you'll end up with two different meshes, one original and one deformed.

Apply your modifiers in both the objects (starting from the upper in the stack).

Then create a basis shape key for the original mesh, select the deformed, shift select the original and use the "Join as shapes" function.


when i insert a keyframe with a single bone selected to a ik chain does not animate properly

well the solution was to select all bones of the armature when going to insert instead a single one, and then ik chain works again, but still this is not normal tho...


You have to reassign the influence of your eyelid bone to the eyelid vertices of your mesh.

As L0Lock said, you can fix your problem in Weight Paint mode, with the Mix or Substract brush.

You can also do it with the Vertex Groups "Assign" button:

Select your object, go in Edit mode, go in the Properties panel > Data > Vertex Groups.
In the vertex groups list, select the vertex group that has the name of your eyelid bone.
On the right of the vertex groups list, there's a down arrow that gives access to a menu. Press Remove from All Groups. Now there's no more vertices in this group, so the eyelid bone can't move anymore vertex.
In your mesh, select the vertices that are supposed to be part of the eyelid vertex group.
In the vertex groups, keep the eyelid vertex group select, and click on the Assign button that is under the list. You can modulate the assign ratio to give more or less influence to the brush.


How could I model a realistic broken pillar (concrete)?

If you plan to texture this, read through all the steps once before beginning. There is a UV mapping tip at the end that requires planning in advance.

Now let's get on with it...

Start with a cube, make it tall

Add a plane and fractal subdivide it

Fractal subdivide it again

This time a little more "fractally".

(If by any chance this is going to be a game asset go with a lower number of subdivisions.)

Extrude your subdivided plane to give it thickness

Set up a boolean (Optional: Subdivide the column too)

For the boolean, set the Operation to "Difference" because you're carving out of your column.

Subdivide the column (non-fractal) if you want the two meshes to be of similar density. Having a denser mesh would be better if you plan to do something like mutires sculpting on this. Having a less dense mesh would be better if this will be used as a game asset.

Apply the boolean, delete any leftover unneeded geometry

Apply the Boolean Modifier from Object Mode.

Then you can move your plane object to another layer or even delete it. After moving it you can see the subtractive boolean result.

To clean up stray geometry you don't need, select any part of those pieces in Edit Mode, press CtrlL to Select Linked geometry, then Delete (X) it.

Note that this is just a start. You can further sculpt this of course.

Bonus Tip: UV Mapping

Since your reference image has textures I will mention a texturing tip. If you plan ahead you can UV map this whole thing neatly. Booleans respect and will combine UV data.

UV unwrap your plane before you subdivide it. From the top, "Project from view (Bounds)".
UV unwrap your column before subdividing and before applying the boolean. "Smart UV Project" with an Island Margin of 0.1.
To place the fractal-subdivided UV island: Select the five flat faces of the column (may need to Select Similar (ShiftG) > "Co-Planar" if you've subdivided the column too). Invert the selection (CtrlI). In the UV/Image Editor Box Select (B) the rest of the visible vertices and scale/grab to position as desired.

An example of the sort of UV layout you can create:

Note: In the screen shot above the column was not subdivided before doing the boolean. It is a different .blend file from that of the preceding screen shots.


Well, another option would be to use limited dissolve in edit mode. What this does is find subdivided faces that are relative to one another, and share the same position (i.e. a subdivided plane), and merge them into a single face. This would make a subdivided face a normal face once again.

Do this by going to edit mode mesh > clean up > limited dissolve. This function has been useful for me, and I hope it will help you!


Print a timer in Python to see how long to run a script

This is one of the fastest way I know:

import time
import random

then = time.time() #Time before the operations start

#DO YOUR OPERATIONS HERE

now = time.time() #Time after it finished

print("It took: ", now-then, " seconds")

time.time() Will give you the current time in seconds.
There are other way of doing it, but this is one of the best. I have always used this and it gave me no problem at all.


First, all your fluid simulation participant objects must be within the bounding box of the domain object.  So any inflow, obstacle, outflow etc. meshes should be encompassed by the domain.

The also seems to be a problem residing with your inflow object.  You must set the Volume Initialization to Shell or Both.  I don't know why this would be the case, but it's the only way I could get it to work with your blend file.

Update

I think that this maybe had something to do with your inflow object having it's origin outwith the geometry, can't really be sure.

I strongly advise you to read the Fluid Simulation documentation as there are a lot of caveats to specific objects.

Here's a final screenshot

And the updated blend file:


For this kind of pattern repeating around a circle, Array and Simple Deform modifiers can often be a good solution:

Create your pattern, as it is symmetrical use a Mirror modifier.

Give it an Array modifier to repeat it. Choose the Count you need, enable the Merge and First Last options.

Give it a Simple Deform modifier / Bend mode, choose an Angle of 360°. If you see that it twists strangely, you need to apply the rotation of the object.

Give it a Subdivision Surface modifier and Shading > Smooth it in the T panel. Now you can work the mesh as much as you want until you're satisfied. When you think it's ok, apply the modifiers and merge the first and last vertices with a Remove Doubles.


how can i connect two armature bones at the root?

I believe you are asking how to have 2 Armature bones with the SAME root---

OBJECT MODE>SHIFT+A - Add Armature

EDIT MODE> RMB Desired Root> E (to Extrude)

RESELECT THAT ROOT and Extrude Again.


Assuming your mask is greyscale, in theory you can map each of the 255 intermediate shades of grey to an individual land-class. In reality, you probably want more separation between the values so that texture compression doesn't mess up your mask. So assign 0 to rock, 32 to dirt, 64 to grass, ... 255 to sand, etc

Your mask will look like this, then it's up to you to setup the node materials to interpret this mask.

The only downside of this approach is that you have very little control over the blending of these terrains. Using the example above, it would be impossible to blend between sand and rock, since these values are not adjacent to each other on the mask. So with a typical bilinear interpolation, you might get 'rings' of landclass like this:

You can do 2 things: use a noise overlay on the mask to break up the pattern so it looks less obvious, or use a depth based terrain blending technique.

The node for this will be very similar to this: Cycles shader multiplexer node?


How to highlight parts of my scene - strategy for materials?

I'm answering my own question as none of the answers was quite what I was looking for, but there were gems in there that let me figure it out. Thanks to all those who answered!

My solution:

I forked local copies of materials, e.g. Aluminum is now Aluminum.Gearbox, Aluminum.Manifold, etc. Thankfully, no component has more than 4 materials, so this was much less painful than I was thinking it might be.
I created my orange highlight material (some glossy, some diffuse and some emissive), using a node group to make it easy to place in all the materials where I want it.
I added a mix shader node before the output of these forked materials, and hung the orange color on the other input.
I added an empty, such as "EMPTY_gearbox_highlighter" with a custom property of "Highlight_Strength", going from 0.000 to 1.000.
I added simple drivers on the Fac of the mix shaders for all the materials in the gearbox, to be directly controlled by the Highlight_Strength property on the empty.

I'll repeat this for each highlightable component, and then all I need to do is to animate the Highlight_Strength properties on my empties, and it'll fade all the materials in the gearbox (or other component) to orange, which is exactly what I want!

Thanks to all who gave me the stepping stones to get here!

Here's the gearbox unhighlighted:

And here it is highlighted, just by taking that single custom parameter to 1.000:


How can I make a texture flow along a bent mesh?

Edit: It looks like the problem has been fixed in the last version.

Old answer:

In 2.8 it looks like you need to mark seams and unwrap, then in the Shader Editor use the Texture Coordinate UV socket, play with the Location values of the Mapping node to make the texture move along the object. In the UV Editor you need to make sure that the UV is well placed if you want the texture to go in the right direction.

In 2.79 you can use the Texture Coordinate > Generated output socket instead of the Object output, then plug it into a Mapping node, play with the Mapping > Scale value to have the right proportion. Now with the Mapping > Location value you can make it move.


I am having issues with the pivot constraint

It is a Loop Dependency. You can't make a children object parent father of is father.
A constraint look like a parent in Blender, so you have to make some parents organization in your file.

Arm Rotation is Father of Shovel.
But, Arm Rotation is in the Pivot constraint of Shovel, so, it's child of Shovel.

This parenting are avoid, you have to use bones and armature to simplify.


How to rotate bezier circle with an object following its path?

The following animation shows what I think you are asking for.

(i) keyframe the curve using the key-shorcuts i then t while the timeline slider is at the beginning of the animation sequence.

(ii) Add another object and move it to the edge of the curve.

(iii) Now, with the model selected, hold shift and select the curve.  This should leave the model outlined in orange, indicating a secondary selection with the curve highlighted with yellow(the primary selection).

(iv)  Use ctrl+p and select->Follow Path (several options work for this, I'm not sure what the subtleties are for the various types ;)

(v)  now you should be able to move the curve around and keyframe its different transforms along the timeline.

Where the object and curve are, in relation to each other, when you parent them will be affected by where the timeline slider is when you parent the objects.  Here is an animation that shows what happens when I parented the model to the curve mid-way through the animation.


Why Cant I Sculpt Together These Joined Pieces?

They have been joined so they exist under the same mesh data block, but it looks like they are still separate islands.  Sculpting works on one island of verts that is a closed shape.
You could perhaps separate them back out, move them such that they intersect just a bit and run a union boolean on them.


Which view/panel will let me see and set an object's position?

In the 3D Viewer, press n to bring up the side-menu with panels you can use to edit the position, scale, and rotation of vertices and objects. Also, a quick fix to your problem would be to press A to select all the vertices, then press s, z, then 0.


Copy RENDER OUTPUT (image result) to Windows clipboard?

This is what I found in doing the system clipboard with python: https://pypi.org/project/pyperclip/
As for pasting images, I think the clipboard actually stores them as a URL like image://C:/Users/Jaywright/AppData/Local/.temp/save_here.png so you might try that in just the regular python IDE to start with.


How do i connect two meshes together without ruining the topology

Try to reduce the edge loops' amount using diamond quads. They're very helpful for making the mesh less dense in certain parts. Also helps to create the proper edge flow defining the model's shape in some cases. In the example pictured below I reduced the 24 vertices loop to 12 vertices loop.

Diamond pattern- loop reduction from 3-1, 5-1 and 5-3 examples:

Another loops reduction method is pictured below.

Loops reduction from 4-2, 6-2 and 7-3:

Note: The complete answer to your problem is in the link @LukeD provided in his comment, but since I've done this topology presentation for my friend some time ago I decided not to waste my efforts and share it with you. Hope it'll be helpful :).


The simulation is likely only running on one core (with another core being partly used for scene updates).

Many (particularly older) physics simulators are single threaded, or at least some steps are. Multi threading in physics simulators is very hard due to all the possible inter-dependencies between objects, see also: Is Physics calculation multithreading possible?

Blender's rigid body engine is Bullet, which does support some multithreading, but I don't think that part has been integrated with Blender, and from what I hear, still has a fair bit of overhead.


How to get rid of imperfections after applying subsurf?

I managed to solve it!

I deleted the vertical edge loop (Alt + RMB) then X → Edge Loop
Then Ctrl + R to make another vertical loop cut and I was more careful not to slide it as far.

This is how it looks now

This is how it looks in the edit mode with the new edge loop

I don't know if it's the right thing to do but it worked for me!


Move wave texture along object with keyframes (in cycles)

In the mapping node choose either "Texture" or "Point" options.
Then adjust rotation to the angle you want and then animate the location for the desired effect.
I am attaching a screen shot of how.


How to load or manage large OpenStreetMap file in Blender for simulation

If you haven't seen it yet there is an addon to import OSM data

When it comes to working with and rendering large scenes there are some things you can do to make it easier.

Use particles or linked duplicates. When objects use the same mesh data, only one copy of vertex data needs to be held in RAM, when the polygons are drawn they get "transformed" into position based on the location of the duplicate item being drawn. If you haven't seen the post about the island flyover video, the island has 450,000 tree and rock particles which reports as over 1 trillion vertices at render and was done in 12GB of RAM.

When creating the scene, set the display of each object as bounding box, this will keep the number of vertices used to draw in the viewport low while rendering will use the detailed mesh.

Then when you want to see what a part of the scene will look like, use render border ⎈ CtrlB to define a small square in the viewport before you switch to rendered view to see the full detail in that area.

Use tricks used in 3D games. Keep the objects low poly and use materials and normal maps to make them appear more detailed. You can use some higher poly meshes in the area you want to zoom into and keep the remaining 90% of houses with low poly counts.


Can't seen primitive options when adding a new mesh

I'd somehow hidden the 'Operator' panel.

For reference for anyone else:

Open the Tool Shelf 'View>Tool Shelf' then click the tiny plus icon just above the 'View Select Add' menu. It should be at the very bottom of the Tool Shelf Panel.


Although you didn't specify, it sounds like you are using the Add Images As Planes add-on.

You'll want to pay attention to the Operator Panel options that appear while the file browser window is open.

These options are contextual and vary depending on whether you are using Blender Internal or Cycles.

For Cycles it will look like this:

Be sure to select either Diffuse & Transparent or Emission & Transparent. With the former, scene lighting will affect the image texture. With the latter it will be shadeless.

You will also have to check the Use Alpha option. You can select either Premultiplied or Straight alpha, depending on which schema your file uses for its transparency.


Best lighting for minimal shadows for product-on-white rendering

To achieve the desired result it's best to create two scenes: the first one for the product, the second for the shadow.

The first scene contains the product and all lighting like lamps, HDRI environment etc. for lighting the product as it should look like. A floor maybe for light bounces or blocking light from below the product. Set Render Properties > Film > Transparent. Hide the floor from the camera by disabling Object Properties > Visibility > Ray Visibility > Camera.
Create the second scene by copying the first one (a word on linked duplicates at the end of this answer). Make the floor visible again by enabling Ray Visibility > Camera and enable Visibility > Ray Visibility > Shadow Catcher. Delete all lamps, set World > Strength to 0.0, put a plane with Emission shader above the product and play with the settings until the shadow is correct. Now hide the product from the camera like you did with the floor in the other scene.

Now both scenes are setup for rendering. In the Compositor, choose a Render Layer Node  for the shadow scene and use an Alpha Over Node with a white colour to put the shadow on a white background. Add a second Render Layer Node for the product scene and place it above the shadowed background with another Alpha Over Node.

If you hit F12 now to render the image, both scenes will be rendered and composited together.

You can now maybe save the setup as a stage for other products. If you want to change something on the product or the floor without having to create the shadow scene again it's best to make those objects linked duplicates, so any changes will apply to both of them. It's important that they're not the same objects just linked to both scenes, otherwise they cannot have different viisibility settings.
A last side note on rendering with Color Management set to Filmic: because it has a much higher dynamic range, the 'normal' white with a brightness of 1 will usually be a light grey instead of pure white. To achieve pure white in Filmic the background white must have a brightness of around 16.19 - which means, the shadow seems to disappear. Considering you want to render with Filmic it would be the best only composite the shadow and product over a transparent background and add the white in another program like Photoshop, Gimp etc.
//Edit: I've uploaded a file where I show the things described in the comments.


All you have to do is drag and drop each clip so they are right after each other in the correct order. Then make sure the length of your animation is the same as the length of the 3 clips (you can set the frames in the render tab of the properties panel). Finally, select your output format (output panel of the render tab) and render the animation. If you have nothing else in your scene it should render very quickly. If you have anything else in your scene, the VSE will override everything in your scene and the final animation will be only what is in the VSE.


Rotating actual object to face outward using arrary and empty

This can be done in 5 easy steps

Move the origin of the object, to the same location as the empty.
Uncheck relative offset from the array modifier.
In edit mode, remove the rotation from the box.
Now move the box to directly out to one side from the origin of the object.
Rotate the box to the desired rotation.

Keep in mind, that it may be easier to simply create a new object, texture it, and use a new empty. Put them in the same place, and in edit mode move the cube away from the origin along an axis (y or x). Then rotate the empty, and you should be good.


How to build blender with Outliner Branch (or any other branch)?

In order to build the outliner branch you switch to that branch first.

git checkout soc-2019-outliner

Make sure that the branch is up-to-date:

git pull

Then you're ready to build.

make full

When you want to switch back to the master branch the command is:

git checkout master

Unfortunately you can't directly apply the OptiX patch to the outliner branch because of incompatible code changes that cause merge conflict.


Animating a plane in the graph editor with local transform orientation

You cannot manipulate keyframes in local transform, they are stored and displayed in global transform only.

But you can parent the plane to an Empty and orient the plane through it. The plane's global animation is then transformed into local space of the Empty. This might be useful for simple short movements, but non-usable for larger animations. With more complicated movement you could have multiple empties and a dynamic child-of constraint to influence the plane only on sections of the animation. How to setup that is covered here:

How can I build a versatile camera rig which can both orbit around its focus and pan?


Texture for 3D models are transparent at places

This is cause by your material's blend mode.
You have 2 options:

In Material settings uncheck Show Backface
Change Blend mode to Opaque (this will fully disable transparency)


How to reset a Grease Pencil object's vertex colors

This is a fairly common and troublesome problem when working with grease pencil objects.
The issue is that, at some point while you had the GP objects selected, you entered Vertex Paint mode. Blender, assuming you were going to paint your grease pencil objects, created vertex paint data for them that now overwrites your material data for in material preview and renders.
Unfortunately (and in many cases problematically), there is no way to undo this with the default Blender interface (at least as of 2.83, and I don't believe recent versions have fixed that.)

You can, however, use a short python script to reset all your grease pencil objects.

Go to the text editor and click the + New button at the top to create a new Text datablock.

Use the following script, including a short function remove_vertex_paint() that removes vertex paint data from a grease pencil object. The two lines at the end will iterate through all grease pencil objects in your blend file and remove vertex paint data from them.
import bpy

def remove_vertex_paint(gpencil: bpy.types.GreasePencil):
    for layer in gpencil.layers:
        for frame in layer.frames:
            for stroke in frame.strokes:
                stroke.vertex_color_fill = [0.0, 0.0, 0.0, 0.0]
                for point in stroke.points:
                    point.vertex_color = [0.0, 0.0, 0.0, 0.0]

for gp in bpy.data.grease_pencils:
    remove_vertex_paint(gp)

Press the play button at the top of the text editor to run the script. Afterwards, you should be able to see your grease pencil materials in material preview and rendered mode again.

It's important to note that this will reset all grease pencil objects in your entire blend file, not just the one(s) you have selected, and not just the ones in the current scene. If you want to keep vertex paint data on some of the grease pencil objects, you need to replace the last two lines of the script and only call reset_vertex_paint() on the objects you want to:
remove_vertex_paint(bpy.data.grease_pencils['GPencil'])
remove_vertex_paint(bpy.data.grease_pencils['GPencil.001'])

And note that the names used here are the names of the grease pencil datablocks, not the names of the objects themselves:


How to assign vertex groups and bone weights through Blender's Python API?

vertex_groups method .add() first argument is a list of vertices index, I  group my input to reduce the calls to add to the minimum necessary.

Note: my input weights are stored in unsigned bytes (0-255).

First with a dict {grpID: ...} then another dict as value for weights {grpId: {weight: ...}}, finally the list of vertices id {grpId: {weight: [vxId, ...]}}, at this point the code is quite simple:

        weights = myGetWeights()
        for grpId, wv in weights.items():
            grpName = "Bone_"+str(grpId).zfill(3)
            ob.vertex_groups.new(grpName)
            for weight, vxIdList  in wv.items():
                ob.vertex_groups[grpName].add(vxIdList, 1.0 / 255 * weight, 'REPLACE')


You need to activate the compositor by checking the "use nodes" option in the node editor's menu header (make sure you have the composite tree selected!) It looks like this:

.

This has not been done in your file.


UV Unwrapping makes a mess and misses faces

You simply need to mark all the seems correctly and it will umwrap nicely. Make sure you mark all the small edges that could interfere with the unwrapping and try again.
Use ctrl+e while in edit mode to call the Edge menu where you can find Mark Seam.

It is also a good idea to apply scale of the object to get expected results when unwrapping. You can do that with ctrl+a with the object selected in object mode:


How do I get a Roblox Stormtrooper helmet to not be greyed out?

There are a few reasons why this could be happening.
Listed as follows are some, with their solutions.

You are using EEVEE renderer instead of Cycles.
Change this by going to the Render properties tab, and setting the renderer to Cycles.

You don't have a material set.
Go to the material tab in the object properties with the object you want a material set for selected, and add/adjust your material.

You need to adjust the material set for your object to something other than the default.
In the images, I try to achieve a material somewhat like a stormtrooper helmet.
First adjust the roughness, then adjust the metallic-ness of the Principled BSDF.

I believe you are doing this already, but it is always good to *Compare your object material to another object in the scene, with Rendered view selected.
In these photos I compare the cube object with the helmet material to a blue Suzanne "monkey" head. (Also with a principled shader.)

With no shader adjustment:
With roughness set to 0:
With final material:
One last tip: Adjusting world shader can sometimes give you a better preview of your materials. Here are examples of world brightness and color with a scene of objects with the helmet shader:
Sometimes a dark world background with a bright light helps too:
I hope this helps!


How do I transform two objects to the same frame of reference

As suggested by @MarkusvonBroady. I positioned both objects in the desired starting position. Then I selected both objects and pressed Ctrl + A, and then selected Apply all transforms. After that, the objects both had the same frame of reference, same angles of rotation etc.
We can also select individual transforms to apply, for example, we could just apply rotation.


Polygonal modeling vs. digital sculpting

In my personal opinion sculpting is better than polygon modeling - it's because in this world there is no perfection, so when you sculpt the model looks alive and like having a soul in it.


Keep smooth shading but simply use 2 very close control points at your sharp edges. This way you can control your bevel shading perfectly, the closer the points, the sharper. The drawback is added geometry (one additional curve segment).

Here is a sharp edge with a single control points. No sharp edge:

Instead, the same edge but using 2 control points very close to each other: