You need to get a reference to that material, then its node tree, then the principled bsdf node, and finally the color input field.
First make sure you have python tooltips enabled in your preferences :

And then you can get the path to most fields just by hovering over it or with right click > Copy data path.
See this question for more information.
In your case you could access this particular field from this particular material with :
import bpy

def draw(self, context):
    layout = self.layout

    # The name is case-sensitive :
    mat = bpy.data.materials["Material.005"]
    # Assuming you didn't rename the bsdf shader :
    principled = mat.node_tree.nodes["Principled BSDF"]
    # Add the property in the layout. This will automatically create a color field.
    # You can access inputs / outputs directly with their index or with their name as a string

    layout.prop(principled.inputs[0], "default_value", text="Color")  # Text argument is optional

Result :


Okay, well, I think I found what I was looking for. I'll post the link for others who are curious. Just wasn't looking up the right keywords.

The answer is by using Boids in blender. Boids allow you to create a model and then apply it as a particle to create a "swarm" effect. The link shows how to create a school of fish that move in a manner like particles by using Boids in Blender.

https://cgi.tutsplus.com/tutorials/create-an-animated-fish-swarm-in-blender-using-particles-part-1--cg-13929


how to set the position of the camera with respect to an object of the scene?

add an empty

parent the empty to the camera

now you can set keyframes on z-rotation for the empty on frame 0 (0) and frame 100 (360)

add location keyframe for the empty on frame 100

move your empty to your second point of interest

keyframe new position of empty at frame 150

now you can set keyframes on z-rotation for the empty on frame 151 (0) and frame 250 (360)

you can repeat step 5-7 for several points of interests, but of course you have to adapt the frames!

if you prefer to watch tutorial videos (which i do too because it is much to follow), check this out:
https://youtu.be/_RqDQuLfV1E
UPDATE:

to set the camera to a position just change x,y,z coordinate you want
add "track to constraint" -> choose target your cube/building/whatever
repeat steps from above to rotate the camera around the building

you can also check my tutorial for this:
https://youtu.be/B4jk75gbQwo
UPDATE & hint:
if you do not see all tabs, just hover with the mouse over it and scroll up/down to see more.


How can I associate collections with different view layers?

It should be pretty straightforward.
I didn't understand the shortcut you used to disable collections from your question. This is how you exclude collections from view layers in the outliner :


How do I add together two a⨯a images to a single 2a⨯a image in the compositor?

I suggest a different solution:

here's the Compositing setup:

The first node (image node) is an empty image (generate in blender as 100% alpha image) with the full size of your output image (1024x512). When the alpha image is added to the rendered image, the output (file output) is a 1024x512px file.

Add the second scene (again translated in the opposite direction) and you'll have the two renders aligned.


How do I assign a color ramp to a 360° axis?

You can set a Gradient Texture to Radial for this. Here i combined it with the Object Output of the Texture Coordinate Node, but depending on your geometry you might have to put a Mapping node behind it.


How do you save materials that you create to use them later, in a different project?

Just save it as .blend and use the append function (Edit>append and select the materials)


Measurement tool incorrect against ruler in image by VARYING amounts

The photo has barrel distortion, so the ruler scale isn't linear. Hence the inconsistencies.
Still, you can align it to the grid.

Adjust transparency for the image, to see the grid underneath
Move the 3D cursor to 0mm markings and set it as Pivot Point (using the overlay menu)
Scale the image until the 170mm markings match the grid

(The gif starts with the ruler perfectly aligned)


I have a model and a normal map, can I bake Ambient Occlusion from both?

you need to bake in AO from the geometry, not the normal map...you can bake out the original mesh or possible apply the normal map as a displacement to the current mesh...just add a multires modifier before the displacement and subdivide it a few times.


UV Unwrapping Issue. No visible stretching, but part of the texture appears stretched

It turns out I had a ton of ngons as a result of, presumably, dissolving edges needlesly.


Lagging IK joints in Playback and Exports

It turns out I had my DEF joints constrainted to joints that were constrained to other joints.
When I was originally building the rig, I had to import the rig from MotionBuilers auto-rig set up where I ended up parenting the bones to the IK controls the entire time. So when I switched to FK, my IK controls would just follow the FK. So my DEF bones were constrained to my IK cntrls, then to my FK cntrls.

So after fixing the orientations, and connecting all my DEF joints(Except for the feet), I set my set constraints and switches to the actual DEF.
So instead of DEF -> IK -> FK, I set it up like DEF ->IK and DEF -> FK. Then I used drivers to switch.


The "real" cause of the issue, is the subdivision modifier:

As the subdivision levels does not match in viewport and render, the cloth cash is not valid when rendering.
Turn the *render subdivision levels" to 1 and that will be ok.


Here's a question: which is more high-res, your object, or the normal map? If the object is more high-res, than the normal map is going to hide that with it's low-res faces.


Video Sequence Editor Alpha Over png transparency speed control effect

I found the solution. Actually, it was easy and very intuitive.
First, I added the video and image strips, in the image strip properties chanced to Blend: Alpha Over and next I add the speed control to the video file (only changed multiplayer property, the others are left default).

No need to add Alpha Over effect separately.


It's really easy to solve. There are just not enough transparency bounces in your settings.

Just crank up the max. number of Transparency Bounces to say 18 and the problem is gone. EDIT: 18 works for this view. From an other viewing angle you probably need a lot more. This might result in bad render times...

The problem occurs at places, where the ray has to bounce more. Because the max. number of bounces is to low, it draws an black pixel.

Transparency set to 18 or higher solves the issue


Cycles, or really any renderer for graphics is not a completely physically accurate model of light. Cycles in particular uses an rgb based model for colour, rather than a spectral model (luxrender does use a spectral model for colour which may get slightly better results for stuff like this). As far as I know, neither bother to model things like coherence or polarity or anything like that.

Either way, material properties and light effects are vastly simplified in order to provide visually appealing results in a reasonable amount of time and to make it easy for artists to build materials without detailed scientific knowledge of the interactions between light and various materials.

These kind of rendering engines are not and never will be scientific simulations. If you want to find a scientific simulation of light, you will need to look elsewhere for programs build for that purpose.


How to render Lattice all shape keys to images using python?

Select  lattice object and run script. Iterates thru each shapekey
and renders to "Key:" plus shapekey name dot png to the directory of your render filepath.  Make sure this is set, on linux this is commonly /tmp.

import bpy
from os import path

context = bpy.context
scene = context.scene
lattice = context.object
fp = path.dirname(path.abspath(scene.render.filepath))
key_blocks = lattice.data.shape_keys.key_blocks
lattice.show_only_shape_key = True
for i, kb in enumerate(key_blocks):
    lattice.active_shape_key_index = i
    scene.render.filepath = path.join(fp, "Key:%s.png" % kb.name)
    bpy.ops.render.opengl(write_still=True)
scene.render.filepath = fp

Used render.opengl for testing purposes.  Change to render.render if desired.


How to unlink / remove an object from a scene?

While the active scene is Scene.001 select Cube.001 and press X. You can also right-click   on the object in the outliner and choose Delete.

Deleting an object only applies to the current scene, any other "copies" in other scenes will still remain there.

You can link the object back to Scene.001 by selecting it in Scene and pressing ⎈ CtrlL->Objects to Scene->Scene.001

You can also remove the object using python, you can type the following into blender's python console or paste it into blender's text editor and click run script. Changing unlink to link will let you replace the object back into Scene.001.

bpy.data.scenes['Scene.001'].objects.unlink(bpy.data.objects['Cube.001'])


The cycles diffuse node does not support transparency on its own. In the material nodes you need to add a transparency node and mix it with the textures alpha channel with a mix node. If you had it transparent from the start it might've been using the blender internal rendering engine which you can change from the top bar where it says cycles render and switching it to blender render.

If you plan on atlasing the textures, using cycles does not support transparency when baking textures.


How can I add a 2D asset as a 3D object in the shape of the png minus the alpha?

When using the "Import Image as planes" function (Shift A in the 3D Window), there are options for using alpha, animating an image sequence and use an emitter or shadeless shader.
The 3D shape is not affected, but the result is a cardboard cutout.
The images of the sequence have to be named with the same base name and a progressive number (Object_001, Object_002, .......).
In the shader editor you will use the image texture node to set the duration and the time offset of the animation.
If combined with grease pencil objects the material has to be set as "Alpha clip" in order to work in Eevee, to avoid uncorrect Z depth.


Add confirm upon release event to a custom shortcut

I now understand I've been overthinking this while the solution is simply to set spacebar for panning both in 2D view and 3D view.
For some reason I thought in the 3D view/pan view window I needed to set mouse movement, then spacebar as a modifier and then in the view3D Move Modal section in the bottom also set confirm: spacebar: release to make it work the right way (see image with my overcomplicated setup) It did work but was unnecessary complicated and could not be applied for 2D view.


it can be the progressive refine setting "on": Progressive rendering will make a tile as big as your image -> render time will be long


Combining two IMAGES so they fade into one another in a gradient or transition

I'd say your intuition is correct, you don't even need to remake your materials.
Just use a single plane, and use a gradient texture as a mix value in the Factor socket of a Mix Shader node to fade between the two.

Then copy paste your two materials into the same shader tree and mix them together.

You may use a color ramp node to control the transition.


You can join objects by selecting them (ShiftRMB) and pressing CtrlJ in the 3D view while on Object mode.

The selected object(s) will be joined to the active object.

The active object the one with the yellow outline, usually the last object selected.


How to get a bone’s Pose Mode transform matrix

The PoseBone.matrix_basis attribute works as expected. Use the matrix's decompose method to extract the quaternion rotation.

To test the script, open up a new file, delete everything and create an armature.

import bpy

for b in bpy.context.scene.objects.active.pose.bones:
    # use the decompose method
    loc, rot, sca = b.matrix_basis.decompose()
    # or use the to_quaternion method
    rot = b.matrix_basis.to_quaternion()

    print(rot)

Result: <Quaternion <w=1.0000, x=0.0000, y=0.0000, z=0.0000>>

If you want to use the matrix for other things you can easily make a copy with the matrix.copy() method.


How to fix animation actions that are separated and duplicated onto every bone in the heirarchy

This looks like it was baked "out of" somewhere, rather than the actual (correctly rigged) file. The only thing I can think of, for you to work, would be to arm (create) a basic rig, and apply constraints to those bones to the bones on your given rig.
The second thing you need to do is to "bake" in Blender, each action from each of those bones. That means, you'll delete everything but "walk" from the outliner (save an "original bones with mixed actions" files first), then save the "walk" file. Clean and delete everything that is not "walk", save "walk" file". Do the same for the remaining actions.
Open the "walk" (action only) file and do a BAKE to YOUR basic rig. Delete your given "walk" actions and the previous (broken) rig.
Now you have a completely re-build Walk (baked) action in your new basic Rig.
Go to your ACTION EDITOR WINDOW and NAME the action accordingly (this is important, so you can pick it up, later).
Do the same for all other files.
When you complete all that, you can go to your "walk" (baked) action, and FILE>Append>yourOtherBakedSeparatedActionFile.blend>ACTIONS>Append.
You will now see it on your ACTION EDITOR (name that you given your action from the previously fixed files in their action editor window).
You can now push this action into the NLA, to be exported (file>export>fbx> Press N > export NLA clips and Actions) when you're done editing them.
After all of this, you can now start EDITING whatever you needed to edit.
Here's an in-depth video about what gets exported and what not (from other applications into Blender), this is a recommended watch since you inherited a non-editable file, thus you need to reconstruct it, bake it, organize the actions so you can do your work.


How do I rig each blade to fan out like an aperture lens?

Copy Rotation Constraint + Local Space

I would move the triangle's origin somwhere along the shortest edge.

Then assing to the object a Copy Rotation Constraint pointing to an empty.

We are only interested in copying the rotation on one axis, in this case the Z axis as the blades are in the XY plane.

Notice that we must also change the Rotation space as in the picture above to transfer the rotation of the empty to the object's Local space.

Then we can duplicate the object and control the individual rotation of all blades with the empty:


This started as a question but how I ended up finding the answer I think I should share since I didn´t find anything related to this subject here.

There´s a way of decreasing from 60fps to 30fps. Today if the movie file is  imported straight on VSE and use 30fps the video will be on on slow motion "off course it´s divided by two times right?".

So the first thing it´s import the file using 30fps:

Now select your movie strip and apply an Speed Control and on the setting use the values:

That´s it now your 60fps file it´s at 30fps and you can continue the editing.


Whats problem with my mesh to shrinkwrap?

The project option projects along the normals of the object which is projected.

So here, you need to orientate the eye along the face of Spider Man:


Is there a way to use local transforms without pressing keys twice?

You could set the 'Transformation orientation' to 'local' and show the translation, rotation and scaling arrow (you can use Shift to select multiple of them), and use these to transform your object.


The problem is probably in color management. Go to the render tab, and look for color management. It is probably on filmic at the moment. Change it to standard, and the colors will be right.


How to set this strange anim. keys in outliner?

The little camera and eye icons you use to change visibility in the outliner are toggling object properties.

The eye icon links to the hide property, while the camera icon links to the hide_render property and the cursor is the hide_select property.

To insert keyframes using python you set the property and then use keyframe_insert to create a keyframe with that value.

obj = bpy.context.object

obj.hide = True
obj.keyframe_insert('hide', frame=1)
obj.hide = False
obj.keyframe_insert('hide', frame=10)

obj.hide_render = True
obj.keyframe_insert('hide_render', frame=1)
obj.hide_render = False
obj.keyframe_insert('hide_render', frame=10)


Why does this execute method makes AN stop working

It was inconsistent use of tab and spaces. I used tabs where the document was using 4 spaces before.

The console clearly report this.


You have the Clipping Border active  Alt  +  B , hit the same shortcut to clear it. You can also find the command in the View menu in the 3D viewport header.


You most likely have modifiers that are not visible in render mode, changing the way it will look. Make sure that every modifier is enabled for rendering.


Blender 2.74 (x64 Linux): Application of Hair Dynamics produces unexpected results

Don't worry! I've found my solution.

Convinced that the problem was due to the mesh, I continued to look into things regarding its construction. Whence, I looked at the scale. The X, Y, and Z scales were all uneven, and more importantly not 1.0.

For reasons best known to Blender, if a shape is not scaled "normally" i.e. 1x1x1, it seems to upset the physics engine in this respect.

The solution was to change all the scales to 1 again and using the scale function (S followed by X, Y, or Z) resize the mesh to fit. Since I had an armature, it was unaffected so I un-parent-ed it and made it fit before reparenting.

The physics engine has been happy since.


How to get Blender's temp directory via the Python API?

Python's tempfile module.

First of all, Python has its own tempfile module, which is quite comprehensive and can likely do what you need(handles creating, temp files, directories and optionally - cleaning up when you're done).

Blender's User Preference

If you want to access the temp user preference, you can do so via.bpy.context.user_preferences.filepaths.temporary_directory
... which is initialized based on environment variables (See Environment Variables in the manual).

Blender's 'session' Temp Directory

However Blender crease a sub-directory within the temp directory, for each session, which is cleared on exit (even in the case of a crash).

And this is accessed via bpy.app.tempdir, in the case you describe, this sounds like it may be a good option.

Note that it may work well to use the tempfile module, even if you access Blender's temp directory using Blender's API.


Why is my rendered my image not being saved as a file?

Have you actually saved it ?

Blender does the render and displays it but doesn't automatically save it as an image.

To save it, use the top left of your Image Viewer window click on "Image" > "Save As" and give your file a name and save it.

In 2.8

in 2.79 use the UV/Image editor window

If you want to save the render automatically you need to render as animation (CtrlF12), just set the range to render only one frame.

Do a little more research and/or show that you have done some research next time you want to ask something here. Some folks on this forum don't have quite as much patience as I do and might reject your question for showing too little (if any) previous research


Why is my mirrored object in blender lighter/darker than the original object? Even with a simple cube?

Figured it out! I just hollowed out part of the mesh, on the side that would touch the mirrored object.

And basically just went, delete / faces on that part.

Hopefully this can help others having the same problem.
Here is an image showing what I mean.

http://imgur.com/a/7PIHf


Invisible faces problem in Game Blender Engine

This is most likely the result of flipped faces, resulting in this:

One way to fix this is to disable backface culling like so:

Or you could simply recalculate/flip normals of the faces:

Hope this helps.


Do it by make your armature an Root bone.
1. Select your Armature

2. Press Tab to enter Edit Mode

3. Press Shift + A To add new bone. Name it Root or whatever you want

4. Parent your current Root bone (which mean if you move it, the whole armature will move with it) to your new Root bone you just add.
Select your current Root bone, then Hold Shift and select new Root bone.
Press Ctrl + P then select Keep Offset

5. Now you can move your new bone to the origin and whole armature will go with that.


Is there a way to make the scale an actual representation of the measure system (metric) I use?

If you set up a unit scale for Blender, inputs will parse the strings you enter in any field which expects length.

Supposing you have set the units to meters, and the Unit Scale to .5 (at least, in my build)..

If you enter '1', Blender will always interpret that as 1 Blender Unit (50cm)
If you enter '1m' Blender will interpret that as 1 meter
You can enter '25cm' or '250mm' or '.25m' etc. to refer to that length
If you enter '1in' Blender will interpret that as 1 inch. Because you have declared your dimensions to be in meters, that will be translated to 2.54cm
You can even enter an expression like '25m / 4' to get 6.25 meters

I'm open to correction, but it is true that the last-used radius for object creation can not be made to persist in the .blend file, and reverts to 1 of your declared base unit when you reopen it. However, the last creation size requested (in the tool region) does persist within sessions, on a per-primitive basis.

These are deliberate choices on the part of the developers, not careless. There are many choices in Blender that I don't personally agree with, but in the vast majority of cases, if I stop to think about them, I can see the arguments for the choices having been made that way. Usually it's to do with 'cleanliness'.. i.e. consistency between different parts of what is, after all,  a large application. I have been pleasantly surprised by that consistency in Blender's way of thinking, compared to many proprietary applications, especially those with a long history of accretions .. :)


i had the same problem a few months back, my solution to this was checking for duplicate vertex, check if a face on the inside of the mesh is preventing the merge, and recalculate normals, that or your vertex isnt aligned to 0 properly.
most of the time i fixed it by recalculating normals with Shift N
hope it helps


Sculpting tools don't seem to work unless using remesh or dyntopo

I was able to sculpt when I applied the two modifiers (mirror & sub) and filled the holes in Edit Mode (select all + f for fill). I don't know enough about the sculpt tools but maybe brushes like crease need closed meshes. Depending on what you want to do don't expect high resolution and details without Dyntopo on this one.


This is more of a general software recommendation question, I believe, but one thinks it may be migrated in the future.
I'm familiar with one specific program known as Allway Sync which is for Windows (multiple versions) that can be configured to monitor/check specific locations. When a change is made to that/those locations, the files are then copied/synchronized with the configured destination.
I've used this specific function to prevent data loss for a client, which worked well. The program can also be configured to respond only to a specific device, which means you can exempt a different drive from storing the synchronized files, or alternatively, use multiple drives.
The free version will work until you've performed an undetermined number of backups/synchronizing actions at which point it will request payment. The cost is relative low for such a useful, powerful program.
There may be other similar types of programs available.


How to eliminate, remove or mute audio from video strip

You can just delete the sound strip by selecting it and pressing X or hide it by selecting it and pressing H on your keyboard. Both works fine, though if you want to use the sound later the hiding method is obviously better, cause you can easily unhide it again if needed.


When I parent my model with a Bvh animation the arms cross? why is that?

So the answer to my question is, because my model was not in a complete t stance when I Parent it,  the animation starts on t stance which mess up my model. If this makes any sense lol. So the answer is make sure your model and bvh rig matches up before you parent it.


Caching is done with any type of physics (except for fluid simulation) while playing animation (files are being written to disk while animation is played) and everything will be cleared once any changes of settings are made. Note that you'll be able to edit settings of physics simulations on the fly, and previous cache will be cleared once animation playback started again (new values will be initialized).  It will not start if animation playback was started after starting frame of simulation.
Because of amount of computations done in real time, caching will last longer and speed of animation might be quite slow.

  Caching

  As animation is played, each physics system writes each frame to disk, between the simulation start and end frames. These files are stored in folders with prefix blendcache, next to the blend-file. Note that for the cache to fill up, one has to start playback before or on the frame that the simulation starts.
  The cache is cleared automatically on changes - but not on all changes, so it may be necessary to free it manually e.g. if you change a force field.
  Cache and Bake

Baking will pre-calculate animation taking into account every option set up and animation will not be changed unless bake freed or deleted. Once simulation is baked it is impossible to change most settings of objects used; meshes changes won't be taken into account and old results will be played instead.

However, no computations will be done in real time and animation playback will be faster.

  Baking

  The system is protected against changes after baking.
  If the mesh is changed the simulation is not calculated anew.
  Cache and Bake

Note also that baking physics simulations can be different in options depending on type of simulation, so several settings will depend on what you bake.


Imported object is locked to world origin

A few things you could do to fix this:

1) set the origin of the fbx file you imported to it's own geometry.

You can do this by going to object > transform > origin to geometry in object mode with the object selected.

2) you can set the object to be it's own user.

This is a fix for an error caused by linking objects from other scenes. Somehow your object might have a similar response, so setting it to have it's own user may help.

You can do that by going to object > make single user > object. Or if it has a material or data then object > make single user > object & data & materials & tex.


There's an example of shape keys round-tripping (glTF to Blender to glTF) in the glTF-Blender-IO test suite, which is a collection of .blend files and .gltf files that are used by an automated process to put new versions of the Blender glTF importer/exporter through most of its paces.

The tests/roundtrip/01_cs_morph folder contains a glTF file that is imported and then re-exported, and is expected to preserve the glTF "morph" animation via Blender's shape key animations.

There is also a tests/scenes/01_cs_morph.blend file that is tested via the exporter.  This is a Blender 2.79 project, but the test suite loads it into 2.82 beta (currently) and expects it to export correctly.  You can download the blend file to see how these shape keys look in any recent version of Blender.

It's not clear from the OP screenshots what the problem is there, but start by taking a look at the examples from the test suite to see how it's supposed to work.  If you still have a case where it's broken, please file an issue and include a sample project for testing.


Area Lamp in Viewport in Blender Internal Engine

Area lamps, as you may already know are not supported in BGE/UPBGE 0.2x, however we can still bake lighting such as area lamp lighting onto an image.
Cycles bake tutorial. The same can be done with Blender Render, just with different, compatible materials to that particular render engine.
https://www.youtube.com/watch?v=7pcjenAfFto


How to add a mirror modifier to all objects of a certain collection?

You're better off using bpy.data.objects to manipulate them. This way you don't need to rely on what is selected, all you need is the objects name.
import bpy

mod_name = 'My-Mirror-Modifier'

for obj in bpy.data.collections["My-Collection"].all_objects:
    if obj.type == 'MESH':
        mod = obj.modifiers.new(mod_name, 'MIRROR')
        mod.use_axis[0] = False
        mod.use_axis[1] = True
        mod.use_axis[2] = False
        mod.mirror_object = bpy.data.objects["Light"]


Acrylic Material with Light Transmission

All it took was extruding thickness to my floor sorry I'm an idiot LOL


Easy way of snapping Objects and Faces to vertices?

You need to enable "Snapping".

Switch to the edit mode.

Enable snapping by selecting clicking the magnet icon. Select what you want to snap to.

Grab the mesh and let it snap into position.


How to move an Arduino's servo motors using Blender?

Try looking at this video.  The gentlemen explains, step by step how to control an sevo with python and arduino I think this is what you want.

This isn't actually a blender specific question, if blender uses fully featured python!  The difference between this and "regular" python, (if I'm not mistaken) is that python "here" knows how to talk to blender.

You might want to move this to Stack Overflow, there are a likely a lot more users with these kind of skills there - it's part of the same network of question and answer sites as this.

Remember, once you get this working, you will have to be clever enough to make the python algorithm:

A.) Get the information from blender
B.) Figure out what it means for the servo
C.) Optionally but preferably, do this at an appropriate time!  (ie, whenever a relevant part is moved)

Always Remember: In Engineering, it is important to break problems into their component parts.

If it were me, I would follow the video by itself first - that way, you can actually move the servo, blender or not.  Then make sure a python script that can talk to blender will do this.... it doesn't matter if you have to run the script by hand, at least it will work!

Then once you can make blender move the arm, - even if it doesn't care what is on your screen in blender! - do step "A".  Now you're cooking!  Figure out what the screen means for the server, and make it happen!

Finally, once you can make everything, see if you can work on "C"!  This is the cool part.  Remember everything that look "cool" has had a lot of backround effort put into it.

Inspiring Question! Good luck!


Blender 2.49b opens with all tools and menus super small - how to fix?

Go to "Panels - View all" or press the Home key on your keyboard. This  should align the panels according to the size of your Buttons window.

If you want to resize the panels manually, you can do this by pressing Ctrl and use your Mouse Wheel to adjust the size.


Go into the particle tab of the properties window and add a new particle system to your object. In the particle settings look for the Textures panel and add a new texture.

If you return to the textures panel it should then turn into particle texture editing, along with a pull-down menu to choose texture context from.


Different Enviroment Map per object/layer. (Blender Engine)

By using multiple scenes you can get the different parts and composite them together. Have one scene that renders the background you want, then another scene for the object with the environment you want reflected on it's surface, render this scene with the background as transparent then composite the objects onto the background.

You could setup multiple scenes to get different reflections for each object. The object index can help to mask out each object when compositing.


Pressed something and outliner expands all recursively. How to revert?

The easiest way to fix this is to close one level at a time by pressing Numpad - repeatedly until all levels are collapsed.


Is it possible to make visible spotlight lightrays?

Yes, this is now very easy to do efficiently. Add a spot lamp where you want it, and then add a cube and edit to just barely contain the spot lamp:

Make the material of the cube as shown. Note that the Transparent shader is not necessary, and you can leave the Surface input blank. However you can have a surface material and a volume material at the same time.

Then add a plane as the ground and render:

Since the volume is so small to render, it renders very quickly, this test render took about 3.5 seconds.

If you want to move your spot lamp, just parent the mesh to it with CtrlP > Object.


Objects disappear in eevee render blender 2.8

Totally work fine with me.

Try to load that file in a clean UI(don't load UI) and another build of Blender 2.80.

Also the data in %APPDATA%/Blender Foundation/Blender/2.80(Windows) should be cleared for new preference. (or load factory preference)


You can convert the curve to a mesh (best if you keep the original as well, there is a setting for that), and then snap to the edges of that mesh. The mesh resolution of the converted result depends on the Preview U value in the curve shape tab:

Once that is set high enough, you can select the curve and hit Alt + C to get the convert to popup. Select Mesh from it. Then, set the Blender snapping mode to Edge and snap your vertex to the curve. See this animation for clarity:


Which engine in Blender should i start with?

As newbies we started with cycles(side note, we still are newbies).  Cycles looks incredible. It seems to be the most common for achieving photo realistic renders in blender. The draw back is that, it is a little slower. And if set for shorter render times, it can introduce noise. The blender internal render engine is a fast and solid render engine. It can take a little more tweaking to get photorealistic results. In some cases photorealistic results can not be achieved. It has some features that have yet to be ported to cycles or in some cases are just now being imported to cycles, i.e. freestyle, halo and volumetric lighting. The blender can be much faster choice for animations as far as render time. We chose to focus on cycles first and work with the internal render engine as needed.  We have been happy with our choice and results. If you need features from one engine that are missing in the other blender has a compositor at its disposal for combining images. We still have so much to learn. We will be looking into other render engines as well.

Summary:

Cycles Pros

Easier to achieve very photorealistic results

Cycles Cons

Much slower than the internal engine
Can introduce noise as artifacts

Blender Internal Pros

Much faster than cycles
Has some features that are not present or not as mature in cycles.

Blender Internal Cons

Not as easy to achieve photorealistic results.


How can I freeze part of object while applying simple deform(twist)?

I believe using vertex groups/weight painting would be the best way to accomplish this. In the screenshot below the selected vertices are added to a vertex group and plugged into the deform modifier:

Keep in mind that with weight painting, you can also have areas that are only partly influenced: (more flexibility)

Lastly, there are tons of resources on the web about vertex groups, here is one link to the blender manual.


Clip Start and Clip end not showing in blender 2.81 for sun light

Sun light shadow bounds are now automatically calculated, so manually adjusting clipping values is no longer necessary.
The properties have been removed and the UI adjusted accordingly.


Fixed it by importing the model and armature in a new scene.


BGE: Change physics attributes of an object in real time. (AKA while playing)

import bge

controller = bge.logic.getCurrentController()
owner = controller.owner
boost = owner["boost"]

if controller.sensors["boost"].positive and controller.sensors["is boostable"].positive:
    owner.linVelocityMax = 7
else:
    owner.linVelocityMax = 2

requires two sensors:

"boost" -> requests to boost
"is boostable" -> checks if boosting is available

this does not include counting.

Counting needs a frequent trigger otherwise you count how many times boost was requested, not how long it took. I suggest to add an always sensor with [True Level Triggering]. This way it constantly triggers the controller. The controller is simply an AND controller. There is not need to execute Python all the time.

For better reading this this is placed at a different state. Make sure both states are enabled when starting the game.

Remarks:

I suggest to call the property something like "boost energy" as I guess it should represent some sort of consumed element.

The above system (as you described) is a very easy and simple system assuming t the amount of consumed "boost" is constant. If that is not the case you can indeed create a system that takes away a part of the boost value (immediately reducing the property value) and results in a velocity change. This requires the code to run at each single frame.

I'm not sure if changing the max-velocity can be considered as "boost". The max-velocity applies to all physics calculations inclusive falling.


Is it possible to make an optically functional camera lens in cycles?

I already tried things like this, but on a much smaller scale. If you want to be sure that your project works, you should try Luxrender because it is based on a physical simulation.


How do I export multiple separate objects in an obj file?

The lines that follow show that your two cubes are contained as two separate objects:
*snip*
o Cube.001
*snip*
o Cube
*snip*

If the point of failure is how they behave upon import into Unity, it may be better to phrase the question for that community.
Also, exports to FBX are supported in Blender: http://docs.unity3d.com/Manual/HOWTO-ImportObjectBlender.html
In any case, there's no way to further separate the object coordinates in obj format than they are already, other than exporting each cube to it's own file.
Are you perhaps asking "How do I independently manipulate two objects from a single obj file in Unity?"?
Hope that helps.


UV grid only showing on the uv/image editor not the 3d view

Judging from your screenshot, you're using Cycles Render engine and Textured View in the viewport. Cycles in this case behaves like this: It will show the image texture node on your model which is at the moment selected in the Node Editor (in the screenshot i marked it in a red circle), no matter if it is connected in the Node Tree or not. If you click another Image Texture Node in the Node Editor, the viewport will show you this one. Not seeing any texture could either mean you have no material set up at all, or an Image Texture Node is selected which does not provide any output at the moment.

The material preview mode on the other hand will give you a representation of the "real" material output, i.e. it tries to evaluate all nodes which are connected and show the result, independent of your selection.


TexDraw doesn't actually draw anything onto the model

You have created a Texture Mask, and as it is completely black you can't paint anything, you need to remove it:

Also maybe lower the stencil Opacity:

And make sure the normals are correctly flipped (ShiftN):


How can I improve my mesh imported from Sketchup?

Is there a better way to import the files that will give me a cleaner mesh?

This is less a Blender question at this point than a Sketchup question; The import isn't making all the tris, Sketchup is. Perhaps see if there's a "quads" export option.

Assuming that isn't an option  (because if it is, you can stop reading), you have two options;

1: Retopologize the mesh (either by modifying the current mesh, or by making a new mesh on top of that one with the intention of recreating the same shape with a different edge flow)

2: Don't model in Sketchup first (obviously not applicable for this model, this is future-looking).

If my memory of Sketchup holds true, it isn't concerned with per-vertex manipulation, it just allows you to make shapes and plunk them together. That said, you will always get haphazard meshes from it. If you start with Blender, you can keep edge-flow in mind from the get-go, and you can skip all the cleanup or remeshing.

  Do I need to add Loopcuts and new edges everywhere to get rid of the triangle faces?

No. Yes. Kind of both, depending on what you need;

If the mesh needs to be one continuous part with no missing faces (otherwise referred to as "manifold"), then you do have to make loop cuts if you want consistent edge-flow (particularly on meshes that use subdivision modifiers).
If is can be multiple parts, you could make, for example, one part for a roof section, and one part for the walls. Then, if you want to add a windows, you wouldn't need to loop cut all the way around the roof every time.

Also, in general, if you are working on hard surfaces (mostly non-biological, like a house, or a car) you can forgo loop cuts throughout the model by carving up a face, then terminating the edges locally. For example, let's say you started with this house (forgive the quick model);

Now, you want to add a door here, but then these would be the loop cuts;

Yuk. Instead, you could add the following edges;

Now you can extrude out that one face, and you have the start of a door;

(Then maybe you add a door frame, get a little fancier, etc etc);

Of course, this is all well and good, and everything is still in quads, but it can be argued that you've traded one problem (bad edge flow) with another (poles). What's a pole? Any vertex with more than 4 edges. We've created 2;

Now, this is a VERY wide topic, so you'll want to research both edge flow and poles, but the short version - in this specific case - is that

1: This is a solid structure that might be subdivided, but won't be distorted (like a human elbow or shoulder model might need to deform). So the poles shouldn't be an issue

2: We've hidden them in an out of the way area (which also applies to a human model). At some point or another, many models will end up with poles, even subdivided biological ones. The key is to hide the pole (and thus, the potential artifacting and UV issues) somewhere out of the way (like a rafter, or an arm-pit, or a nostril).

The above example works on windows as well. Not only would you have cut through the roof;

You would have cut through the entire middle of the house (and any other details along the way);

Oof. But we can apply roughly the same process as before. You can use "cut" (the "k" key) to draw the basic shape (hitting enter at the end);

Then use "cut" again to fill in the missing edges (one at a time, hitting enter after each);

Two windows can be achieved with the following pattern;

Of course, now we have 4 Tris. If you want to reduce that to 2, you can add a single loop cut (instead of the 4 you might have tried before, one for each left and right side of each window);

Then you arrange the edges like this (and maybe extrude some faces for window frames, first pulling them out, then pushing them back in);

You could get rid of all Tris, but at this point it's a game of "how badly do I want to have all quads, and what kind of edge flow do I want to maintain?"

Hope this helps!


You could try to use raytraced transparency, instead of Z-transparency:

does it get better?


If you select all of the text strips and then change ex. the color value of the active strip, you can right click on the color and use 'Copy to Selected':


I looked at it, you said it isn't render restricted, It IS. Your rig has a visibility driver system that turns its visibility on and off. I don't know where the controls are, I only know it because I see a lot of drivers going in and out of its restriction settings. I would just delete them if I were you. But if you wish to make use of this function, I think it's best to contact the author for manual.


White frames appear after rendering na animation

Okay, I fixed it. The reason is quite silly - my render layers node wasn't connected to composite... :)
So the solution is to check nodes in a compositor and connect everything what is important.


Animated object exported to fbx does not have any animation

When exporting, tick Include Default Take. Also, since you aren't using bones, you should apply the scale on the model before exporting (CtrlA > Scale).

The animation(s) should now come over with the selected one (in Blender) as the default take.


Deforming/curving a mesh in two directions

If you need to loft a specific set of curves, Bsurfaces is a very good option: it can be used for modelling as well as retopology.

But for this job, probably:

Duplicate ShiftD the front edge of your box.
Rotate it up, and use it to form the back profile, and remove doubles at the corners. (Blue, below) .There are many ways of getting the shape here - the Loop Tools Add-on > Space, Proportional Editing, Vertex Smoothing are all handy.
Select all but one or two of the corner vertices, and extrudeEY,EZ the edges a bit. The sections to be bridged must have the same number of vertices for a clean result.
After selecting the new inner edges, CtrlE Edge Menu > 'Bridge Edge Loops'
In the tool's settings, adjust the number of cuts, and the smoothness, to suit.
Cut the result in half, and assign a Mirror modifier to manually fill the holes, make other tweaks, perhaps using the tools already mentioned.

The approach in this answer is sub-division modeling, in which you keep the hand-made topology as simple as possible (not necessarily regular,)  and let Catmull-Clark sub-d do all the work of creating smooth curvatures. With relatively few vertices, you can manually adjust the number to be equal in the horizontal and vertical profiles to be bridged.

Ctrl-select the path between two symmetrical vertices in one profile - you will see the number selected  at the top of your 3D view. Select the corresponding segment in the other profile, and note the difference.
Add vertices by subdividing edges, or remove by dissolving, to make the numbers equal. Don't worry about where..
..because you now use the invaluable Loop Tools > Space feature to spread the vertices evenly along your chosen segments. If it's a lot of work, you may do this work under a Mirror modifier, to halve it.

You will probably want to match segments with high curvature in separate batches from straighter ones, to maintain sufficient density in those areas.

You could forget the extrusion step, and just bridge the original edges, but I don't think the curve is quite as good.

You can assign your Subdivision Modifier after this, with the rest of your model, so they match.


Denoiser works with algorithms done via feature passes and final image data. It's currently not implemented for the viewport nor for progressively refined renders.

Official Documentation


It looks as though you have a non-planar face.  Since there is no such thing as a curved surface in computer graphics each face gets "triangulated" down to one or more tris (triangles).  So even though a face may only have four edges, it is really composed of two tris, separated by a hidden edge.  This can cause unpredictability when the face is not planar.

To put an editable edge there you can select the two vertices and hit J to join the two vertices.

Alternatively, you can make the face planar by going to Mesh menu > Clean up > Make Planar Faces.


Susu was correct in assuming that there are overlapping sections. More specifically, overlapping sections in which the same border crosses over or folds over itself kind of like if one would write the number 8. Intersecting with another path doesn't cause the evident gaps.


What's a good way to make planks in a pattern from a vertices pattern (see image)

Select all the faces in Edit mode. Press I (letter not number) to inset, then press I again to inset all the individual faces. Only do a small inset so there's a small gap, then without deselecting the faces, press P and select > By Selection to separate your new faces into a new object.

From there you can extrude the faces up, and delete the object containing the filler that you no longer need.


Object set to solid but some parts are still showing up as wireframe

1) Install the 'Mesh:F2' add-on from user preferences.

2) Go to edit mode and change the selection type to face select. Select your whole mesh by pressing A and press F to create faces in empty spaces. After that, select the extra face and delete it.


Set all selected objects to be displayed as wireframe

Yes.

Select them all and set the Max draw type to wire.

Right click on the max draw type menu and select Copy to selected.

This works for many buttons and settings across blender.


Why does the y-axis of one of my objects appear to be backwards?

You have a negative scale - see the Scale panel on the right-hand side. Press Ctrl-A and Apply Scale and the transform should behave as you expect. You may also need to Recalculate Normals once you've applied the scale in case any are left pointing in the wrong direction.


Automatic update of the image in the UV/image Editor

UPDATE: I've noticed that some of what I wrote here originally is unnecessary.  If the Slot mode in Texture Paint is left set to 'Material'  you can simply select a node in Cycles and quickly enter and exit Texture Paint mode to have the texture appear in the UV Image Editor.

That's an unfortunate design choice for the UV Image Editor in Cycles. It could change if people come up with some clear and well constructed reasons for changing the current system so the BF devs might feel motivated to change this.

There is a way around the issue now that Slots have been added to Texture Paint.

(Incidently, to make the slots tab show on the main tab you just have to shift+ click the handle to pin it so the tab is always visible)

The following image shows where to find the selector when default settings are used.

Just be sure to change the Painting Mode to Image since the default is Material.


Is there a way to compute vertex density?

Assuming Cycles, the simplest method is to use the Point Density node.

The Point Density texture calculates the distances from a set of points and can be set to either take those points from a Particle system or from mesh vertices. By using Object Vertices and setting the Object to itself, it will provide the density of the vertices of its own mesh. In the above example, the Vector Transform node is used to translate Object coordinates into World coordinates to drive the Point Density. This ensures that the Point Density is in the same location as the mesh.

Adjust the Radius to affect the influence of each vertex (higher values increase the distance at which each vertex will have an effect - effectively smoothing it out further), increase the Resolution if the results are 'blocky' (higher values will be slower to compute) and adjust the Multiply node to scale the result (here I divide by 1000 to bring it within the range 0.0 to 1.0 for the Emission node).

EDIT : Here's an example using the example from the original question. I've adjusted the settings to produce reasonable results without the circular artifacts mentioned by @LukeD. The artifacts are due to the Point Density also providing values between the vertices (rather than LukeD's approach that generates distinct vertex colors). The artifacts can be minimised by adjusting the Point Density properties - Radius, Interpolation, Resolution as shown :


Final:

Overview:

Seems:

This is how I have placed them, not ideal. Seem should be marked along middle edge for a better result. Just count them and select right one.

Unwrapping:

Use my answer from here and don't skip any step. This is crucial.

https://blender.stackexchange.com/a/78362/29370

Correcting UV:

Now you should have nice straight UV map.

Select middle edge (or edges).

Turn on Proportional Editing and change Falloff type to Linear.

Move selected edges on X axis to minimise stretching. Don't forget to use Falloff scale - MouseWheel.


How do I simplify the polygons of a 3D scanned model?

One way to simplify geometry would be to use the Decimate Modifier.

Add the Decimate modifier set to Collapse, and turn down the ratio.
Click Apply, if you want to edit your geometry manually after.

If you want to see the polygons like in my gif, enable Wireframe in the Overlay menu.

Then just manually select and join faces into one.
Vertex > New Edges/Faces from Vertices
Shortcut: F

There are also other ways to simplify geometry, I didn't want to overwhelm you.


In object mode set the shading to smooth in order to avoid seeing the individual polygons of the mesh when sculpting.

Blender 2.80:
To do this open the "Object" menu in the 3D viewport header and choose "Shade Smooth"

Blender 2.79:
In the 3D viewport press  T  to show the toolbar. In the "Tools" tab select "Smooth" under the Shading section.

Alternatively you can search for the operation "Shade Smooth" or just "Smooth" by pressing  Space  in 2.79 or  F3  in 2.8

Note Dynamic Topology has its own Smooth shading option for Sculpt mode which overrides this setting from other modes and should be set separately.


Why does Denoising take up so much memory?

Like Cegaton said, it uses the other tiles in the memory. Using that logic, I ran a test, and found that if you reduce the tile size (in the performance pulldown) the image renders using much less. My file was usually around 1.3GB when rendering, but as soon as the denoise kicked in, it shot to 9GB, but I reduced tile size from 512 to 256, and now, the entire image rendered with denoising maxing at only 1.7GB.

So if it crashes, just remember that you can reduce the tilesize, and you should be fine.


I can't make my armature affect any mesh deformation

I downloaded your file and got it to work. I am very out of practice with Blender but the file seems to have issues. seems like a lot of vertices for the bear, there is some strangeness in scales of things too. there was a parent loop in the Teddy and armature , when I cleared the parenting the armature shrank. I ended up deleting the whole armature and just making a new one and then the parenting with automatic weights worked.


How do I set up a control bone for a mechanism that follows an arc?

You could achieve that using an action constraint on the arc bone.

First create an animation of the lift going from the lowest position to the highest position (or vice versa) and then set the z axis location of the control bone to be what drives the action. you'll need to adjust the settings of the action constraint to fit the length of your animation and define the range as well.

If your goal is to have the platform move along the z-axis at a constant rate (which is what you would need for it to always be at the level of the control) you could use a circular interpolation for your animation so the change in height would be linear.

However, doing this would result in rapid rotation of the arc bone at the top and bottom of the lift, which may or may not be a desired result.


You can use wget which is a command line tool to retrieve files using HTTP, HTTPS and FTP you can download it from here and these are the installation instructions and how to use

Also rather than coping it to a text file you could have right clicked on each of the six files and clicked 'save link as....' (a easier way) after that just put all of them in a folder and put that folder in the add-on folder


I made a game and I put a skybox or simply box but when I start game the camera isn't displaying it

There is a Very simple reason why your sky box is not displaying. The reason for this is that you did not reverse the normals on your cube.

If you enable Backface Culling and set the normals to display,

You will notice that your normals are pointing outward. This means that you can see them from the outside.

If you reverse the normals, (Select the faces that are pointing the wrong way and click Flip Normals

it will make the normals point inward.

Now you are seeing through the faces pointing inward to the other side.
If you were inside the cube, you will see all the faces properly.


How to move a mesh without disturbing origin point

Simplest way is switching to Edit Mode and moving the mesh instead of moving the object in Object Mode, thus the origin stays in place:

Select the object
Toggle to Edit Mode Tab
Hit A to make sure all vertices/edges/faces are selected
Move the mesh via Grab/Move G or simply use the 3d Manipulators

In order to get precise control about moving the mesh, also see:

Is there a shortcut or hotkey that I could use to access the Transform panel of the properties shelf in the 3D viewport?
How do I rotate and scale edges in Edit Mode?
Constrain to any 2 axes during transform?


This is because the bone needs to be connected to it's parent as shown below, this will solve your problem:


Assign a higher value to Render Properties > Light Paths > Max Bounces > Transparency


By default your extrusion will follow the normal of your face, so if your face is slightly tilted on the Z axis it won't follow the Y axis. If you want your extrusion to follow the Y axis, you need to constraint the extrusion: press E to extrude, then Y. Also don't forget to activate the Clipping option of the Mirror modifier, it will prevent the creation of any inner faces.


How to smooth the appearance of a specified subset of faces without topology changes with a script?

Set your object to smooth shading.

Add an edge split modifier. Apply it if you wish.

Depending on the angle setting in the edge split modifier, surfaces will appear smooth shaded preserving sharp edges.

Internally, the modifier splits edges based on the angle of the adjacent faces.

This will add the edge split modifier and "apply" it. The topology will change.

if 1 == 1:
    name = "pole_piece"

    me = bpy.data.meshes.new(name)
    ob = bpy.data.objects.new(name, me)

    scene = bpy.context.scene
    scene.objects.link(ob)

    me.from_pydata(verts, [], faces)

    bpy.data.objects[name].select = False
    bpy.data.objects[name].select = True

    for p in ob.data.polygons:
        p.use_smooth = True
    mod = ob.modifiers.new("edge", type='EDGE_SPLIT')
    ob.data = ob.to_mesh(scene, True, 'PREVIEW')
    ob.modifiers.remove(mod)


As said in the comments you cannot use HDRIs to cast shadows but the reflections are still showing up. You can't render the first layer without that transparent options else you won't be able to add that Shadow Plane correct? So here is my Solution:
For the first layer enable Environment Pass and then add it in the compositor like this:


Make sure the bevel factor is set to a value of 0.5.
Also make sure your object's scale is applied in all axis.

Be aware that beveling a 2x2 units plane to a distance of 1 unit will likely create duplicate overlapping vertex at the edge midpoint that may cause problems down the road. It will also turn your four-sided face into a large NGon which is largely regarded as bad practice, and likely to create problems for animation and UV Mapping.


A simple approach can be the use of knife project (but depending on the shapes you want for the compartments) :

Here I started from a cube and planes giving the shape of the compartments.

Select the planes RMB
Add the cube to the selection Shift+RMB so that both are selected and the cube is the active object.
Go top view Numpad7
Wireframe mode to have a better visibility Z
Enter edit mode (that will edit the cube but keeping the planes selected) Tab
Use 'knife project' (don't check cut through as we want to keep the base intact)
Then extrude down the compartments E along Z axis

Edit : following the comment, I add here the blend file with step by step explanations :


You can pin UV vertices with P and unpin with AltP. This will prevent them from being effected by unwrapping.

Pinned UV vertices will turn red.


You need to animated the bevel end factor of a curve object.

Step 1: Add curve and change its shape in edit mode.

Step 2: Set key frames for the bevel end factor in the curves panel

And the result:


Add menu entry to generic right-click menu?

As of this commit, thanks to @p2or and @brecht, the bpy.ops.ui.copy_data_path_button() operator now allows to copy the full data-path of the active property under the mouse cursor to the clipboard  which can be used to assign custom values to the active property (only available in latest versions).

Simplified version of the provided example in the patch (integers only):

import bpy

class MouseCursorPropertyOperator(bpy.types.Operator):
    bl_idname = "screen.active_int_property_add"
    bl_label = "Adjust active mouse cursor integer property"
    bl_options = {'REGISTER', 'UNDO'}

    my_int = bpy.props.IntProperty(default=100)

    @classmethod
    def poll(cls, context):
        return bpy.ops.ui.copy_data_path_button.poll()

    def execute(self, context):

        # get the data path
        bpy.ops.ui.copy_data_path_button()
        path = context.window_manager.clipboard

        # get full data path
        bpy.ops.ui.copy_data_path_button(full_path=True)
        full_path = context.window_manager.clipboard

        # split path in class and property
        rna, prop = context.window_manager.clipboard.rsplit('.', 1)

        # set attribute if type is integer
        if type(eval(full_path)) is int:
            rna_eval = (eval(rna))
            value = getattr(rna_eval, prop)
            setattr(rna_eval, prop, value + self.my_int)
            self.report({"INFO"}, "{} set to {}".format(prop, value + self.my_int))
        else:
            print (type(eval(full_path)))
            self.report({"INFO"}, "{} is not an integer property".format(prop))

        return {'FINISHED'}

addon_keymaps = []

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

    # handle the keymap
    wm = bpy.context.window_manager
    kc = wm.keyconfigs.addon
    if kc:
        km = wm.keyconfigs.addon.keymaps.new(name='Screen')
        kmi = km.keymap_items.new(MouseCursorPropertyOperator.bl_idname, type='Q', value='PRESS', shift=True)
        addon_keymaps.append((km, kmi))

def unregister():

    for km, kmi in addon_keymaps:
        km.keymap_items.remove(kmi)
    addon_keymaps.clear()

    bpy.utils.unregister_class(MouseCursorPropertyOperator)

if __name__ == "__main__":
    register()

And as of this commit, thanks to @plasmasolutions you can now add an operator to the menu:

Provided example of the patch:

import bpy
from bpy.types import Header, Menu, Panel

def dump(obj, text):
    print('-'*40, text, '-'*40)
    for attr in dir(obj):
        if hasattr( obj, attr ):
            print( "obj.%s = %s" % (attr, getattr(obj, attr)))

class TestOp(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "object.test_op"
    bl_label = "Execute a custom action"

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

    def execute(self, context):
        if hasattr(context, 'button_pointer'):
            btn = context.button_pointer
            dump(btn, 'button_pointer')

        if hasattr(context, 'button_prop'):
            prop = context.button_prop
            dump(prop, 'button_prop')

        if hasattr(context, 'button_operator'):
            op = context.button_operator
            dump(op, 'button_operator')

        return {'FINISHED'}

# This class has to be exactly named like that to insert an entry in the right click menu
class WM_MT_button_context(Menu):
    bl_label = "Add Viddyoze Tag"

    def draw(self, context):
        pass

def menu_func(self, context):
    layout = self.layout
    layout.separator()
    layout.operator(TestOp.bl_idname)

def register():
    bpy.types.WM_MT_button_context.append(menu_func)

def unregister():
    bpy.types.WM_MT_button_context.remove(menu_func)

classes = (
    TestOp,
    WM_MT_button_context,
)

if __name__ == "__main__":
    from bpy.utils import register_class
    for cls in classes:
        register_class(cls)
    register()


How to hide reference images in different orthographics?

Just move images from center at 1m or what offset would you prefer X and Y axis it's would't be harm for modeling process.Hope it will help you.
Also make separate scene collection and move all references to there as you do so turn on in filter outliner tab with arrow and then next to collection unpin arrow (or next to each image).It will protect you from accidentally move image while modeling.
Sorry for bad English.


a screencast key add-on that displays combination keys like g+x or g+z etc

If you are working on Linux, try a key-mon - small but versatiles app to show multiple pressed keys, easily configurable.

See https://code.google.com/archive/p/key-mon/


I want to duplicate an object accross scenes but without deuplicating the materials attached to it

Turns out copying a whole collection will duplicate materials, this won't happen if you select materials and copy them from the viewport context. Learned something new!


Fading Text In and Out - Video Sequence Editor

Get the latest beta version of Blender https://builder.blender.org/download/ - it will have fades in the Add menu:


Do motion blur shutter curves work correctly?

I experimented with the shutter curve and it actually works like you expected. I have a Picture here showing tests with different shutter curves:

The white diagramm shows the curve I used for that render. As Object I took the default cube and made it glowing white on black background. I think the main trick to achive the effect that you want is to increase the shutter time to at least 1 (I used 1 for my renders) but that depends on the speeds of your objects in your scene.


Rotate Empty on Local X-Axis using Python Script

Your first attempt did not work because (as Ray Mairlot pointed out) the attribute is rotation_euler, not rotation.euler. Further more, with the proper notation it will only rotate the active object, not all objects selected.

This five line script rotates all selected objects by 90° on the local X axis.

import bpy
from math import pi
for ob in bpy.context.selected_objects:
    ob.rotation_euler[0] = pi/2
    ob.convert_space(from_space='LOCAL', to_space='WORLD')

The from math import pi line is just so we can use pi/2 instead of 1.5708 as the value to rotate by.


How can i add specularity, shadows and decals on top of a Blender Cycles bake

Switch to Blender Render or Blender Game, import your baked texture and set the emit to 1.0 to get the full lighting information. Optionally you can then import a roughness texture and set it as specular color to create some effects on the surfaces.

Add point light where light are coming from, inside a room add them on each window. Change the color to match the color of the exterior (sky, green garden, other room). Uncheck Diffuse so it will not emit light and leave the Specular checker.

Now adjust the specular intensity of your material and the hardness.

For the shadow add a sun, keep the same sun orientation that you had used for the Cycles baking and enable shadow, check Only Shadow but keep the Diffuse and Specular checked. Adjust the light intensity to contrast the shadows, set the Buffer Type to variance (to get smooth shadow borders) and adjust the settings. Use the Shadow Box to only include your level to maximize the performances or parent it to the camera and reduce the shadow box so you get shadows on close objects only.

For decays add a new texture completely transparent, you can use an high resolution, then paint or project images on your 3D model using the stencil mode. Blend the image in Multiply mode to keep the lighting informations.

You can then add post-processing filter like Bloom in the logic editor.


How do I change the layer of certain objects in a group?

Be aware the BGE does not know about layers (in terms of logic and object management). The differs between

active objects (residing in visible layers inside Blender) and
inactive objects (residing in hidden layers inside Blender).

This assignment is fixed. You can't change it while running the game.

Finally you do not need to do that.

The trick is to place the linked objects inside the hidden layer. This makes them inactive and therefore available for AddObject.

I usually assign linked objects (even single objects) to a group. I link the group from the target blend file.

This allows me to instantiate the group as often as I like in any scene and any layer.

In your case you can create an instance in an hidden layer. While you run your game you can addObject() all objects of the instance.


Is there a way to get icon_value for the UIList using icon name from enum?

Look at the icons addon.
If you look at the code to the Development Icons Addon will see that it uses data defined in that very UILayout.icon  development_icon_get.py Line 86 in version 1.4 method mentioned in question.
Which if crunched into python console
>>> icons = bpy.types.UILayout.bl_rna.functions[
...                 "prop"].parameters["icon"].enum_items.keys()

>>>
>>> icons
['NONE', 'QUESTION', 'ERROR', 'CANCEL', 'TRIA_RIGHT', 'TRIA_DOWN', 'TRIA_LEFT', 'TRIA_UP', ...

There are over 800
>>> len(icons)
802

Make a reverse lookup, name -> index
>>> icon_ref = {k : i for i, k in enumerate(icons)}
>>> icon_ref['XRAY']
563

Or using items()
>>> icons = bpy.types.UILayout.bl_rna.functions[
...                 "prop"].parameters["icon"].enum_items.items()
>>> icons[100]
('IMAGE', <bpy_struct, EnumPropertyItem("IMAGE") at 0xbb1c6c0>)


How to simulate keyboard ESC command using Python builtin modules?

Here is the solution for Windows I was looking for:

import ctypes

VK_ESCAPE = 0x1B
ctypes.windll.user32.keybd_event(VK_ESCAPE)

Beeing written as a function and appended to bpy.app.handlers.render_pre it simulates pressing ESC on the keyboard and aborts the render.

In my addon I used another solution: it turned out to be possible to replace original Blender main top Render menu with custom one which buttons execute addon's operators instead of original Blender's. It was done by recreating inside the script and re-registering original class TOPBAR_MT_render(bpy.types.Menu) which can be found in your Blender current version folder -> scripts -> startup -> bl_ui -> space_topbar.py

Also I replaced operators for original keymap shortcut settings by editing bpy.context.window_manager.keyconfigs.active.keymaps['Screen'].keymap_items, so in the end user uses the same buttons and shortcuts he used to, but they execute addon's operators instead of original ones, and this is suitable for every system, not only for Windows.


How to apply textures with alpha channel?

It looks like the ground that you are trying to apply the texture to is on the Background layer and is being used as a sort of a mask, so it is not being rendered.  What I did to fix your problem is duplicate the ground, move the duplicate in the Z direction just slightly to avoid it intersecting with your ground that is being used as a mask, and then move the duplicated ground onto the foreground layer, which you have defined as the first layer, by pressing M.

Now the ground will render.  Next, you need to apply the cracks as a texture to the new ground.  Applying textures with alpha channels is simple using cycles.  Here is the node setup that is used:

Now if you render your should be able to see the cracks.

\


It appears that collisions while sculpting will arrive in 2.91..not 2.90: https://wiki.blender.org/wiki/Reference/Release_Notes/2.91/Sculpt


How to create this extruded piece from a rectangle?

I would probably start with an "Inset" operation (I) to create the geometry for the center hole, then move it slightly on the Y and Z axis and then eventually remove the face in the middle of the inset. Further detailing steps (such as solidification and bevelling) are of course necessary but that should give you a starting point.

If that's not what you were after, please clarify the question. I'm assuming you want to model the pictured piece in Blender.


Object/edit mode is not related to UI.

I think one issue here is that some add-ons do not handle their init code correctly (assuming keyconfigs are always present in wm, which iirc is not the case when Blender is started in background mode, a lot of things get disabled then).

So a first thing to try is to start blender with --factory-startup option, which only enables official add-ons (which are supposed to behave correctly).

Second point is that, afaics, you do not select anything in your mesh before calling the dissolve operator? So if no faces are selected in existing objects, dissolve cannot merge anything…


Shear in object mode is not intended to shear an object mesh but to shear several objects from their locations.

But you can use a 'lattice modifier' in order to shear an object in non destructive way:

Above on left an object sheared in edit mode.

On right, another one with a lattice modifier. The object is not sheared but the lattice is itself sheared in edit mode.

To do it:

Place a lattice at the object location.
Add a lattice modifier to your object and set the lattice as 'object' in the modifier.
Enter edit mode for the lattice.
Shear the lattice.


Select all the faces you want to assign the texture. Press 'U' and click in 'Unwrap'. If the texture is already assigned to those faces it will automatically distribute the texture. If not you can go in 'Material Properties' in the right side of the screen and click 'assign' with the texture you want selected.

If you want your bricks to be smaller you can create a texture map in your node ang set the scale of the texture higher. This will make the material look smaller in the mesh but will also show its rectangular pattern if it gets too small.

Best regards.


Can someone help out with a better approach for this model

You could create a material that would be a mix between Voronoi (Distance to Edge mode) and Noise, with a bit of Emission in order to fake translucency:

Then add a particle system with a collection of gravels. To vary the amount of each gravel, use the Use Count option:


Unable to select whole mesh in edit mode

It was a simple problem. Other faces of the mesh were hidden.

The answer was to unhide them with Alt + H in Edit mode


How to remove blur off toon shading blender render

What you are seeing isn't a blur, it is reflections and highlights.

You can either turn the size and smooth down to zero for the diffuse and specular settings -

or enable shadeless to eliminate all highlighting.


Select all your dupligroup instances and on the active one change the dupli-group group. Then righ-click the input field and select Copy to Selected:

This will change every object in selection.

You can use this technique on many object properties.


I copied and pasted an object from a different Blend. Maybe that's why it was locked. But why is that?

If you link an object from another file, it can only be edited in that file, not the one you have added it to. What Blender is doing is making an exact copy of a portion of another .blend file, and reverse connections are not currently supported (being able to update the linked .blend). You will need to Import the mesh in order to edit it.

Changes to the source .blend file will not be automatically visible in the linked mesh, you will need to re-link or update the mesh.


Textures split up when using "Data Transfer" modifier

Delete Data Transfer modifier.
Create a UV map.
Create a new image in the image editor.

In the low poly object's material nodes, click the blue thing to make it a separate material from the original object's.
Unlink the image from the Principled BSDF and select the new image.

In the original material, plug the texture into the Material Output.

Select the original object then the low poly object so that it is active.
Make sure the disconnected image node is selected in the node editor.

In Properties Editor → Render Properties, set up the Bake section something like this.(This section is only available for CPU rendering.)

The Extrusion setting is the one to fiddle with.
After setting the render samples to a low number (1 worked for me), click Bake.

This should leave you with a nice new image texture that will work with the UV map that you created.


How to export object with its texture for 3d printing?

I originally followed this tutorial where it outlines smart unwraping as part of the UV creation process. I started from scratch, and instead of doing the smart unwrap with island spacing, I just did an unwrap (more like one of the posts I looked at) and things now work as expected. The only downside is that some of the geometry has warped into very small triangles on the PNG file, but this isn't (in this case) a big issue.

PLY's still don't embed the data, but that's a problem for another day :)


Dual brush function in texture painting?

Edit: No, there isn't a way to switch between two textures based on pressure in the brush itself. The example given shows how to switch between two colors with the same mask texture used, which is closer to what the linked video showed at the time mark given. IF you simply want to mix two textures, one can be set to the brush texture and one to the brush texture mask, and use separate mapping.

If the gradient is what you are looking for, here is a quick example of the settings to use with a 'Texture Mask' brush and using a two stop gradient set to pressure.

Here I set an image of a square to the main brush texture calculate alpha, rake and use stucco on brush mask set to 'cutoff' for pressure. I hope this one maybe helps. Square has to be mapped to like 1.60 instead of 1 so that there is visibility of the edges inside the brush sphere.


Selecting keys in Graph Editor from different channels at same time and value?

Answering my own question: I finally realized that I was clicking again on the key to move it-- which deselected the other channels. Need to click-drag away from the keys to move them together.

BUT... when multiple keys are selected the numeric boxes disappear from the properties panel! Is there a way to assign a single numeric value to multiple keys?


Model and materials turn black after I reopen the project

Painted textures need to be saved as image files first.
Blender doesn't save them for you when you close then project or when you save the blend file.
Unless you save the textures manually you will not get them back next time the project is opened.


unable to run two (or more) scripts together

Using the rigify addon as an example, you add a custom property to the armature that holds a unique rigID for each rig, then you register duplicates of your operators and panels that are customised for each rigID.

rig_id = "ThisRig"

class Rigify_Leg_FK2IK(bpy.types.Operator):
    """ Snaps an FK leg to an IK leg.
    """
    bl_idname = "pose.rigify_leg_fk2ik_" + rig_id
    bl_label = "Rigify Snap FK leg to IK"
    bl_options = {'UNDO'}
    ....

class RigUI(bpy.types.Panel):
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_label = "Rig Main Properties"
    bl_idname = rig_id + "_PT_rig_ui"

    @classmethod
    def poll(self, context):
        if context.mode != 'POSE':
            return False
        try:
            return (context.active_object.data.get("rig_id") == rig_id)
        except (AttributeError, KeyError, TypeError):
            return False
    ....

As an example, if you were using rigIDs of char1 and char2 then you will find the following classes registered -

bpy.types.pose.rigify_leg_fk2ik_char1
bpy.types.pose.rigify_leg_fk2ik_char2
bpy.types.char1_PT_rig_ui
bpy.types.char2_PT_rig_ui


Since there is no switch node, I just created groups of the setup that I did earlier (switch shader and switch color). It's limited to 10 inputs, but that should be enough for what I'm doing...otherwise I will extend it.
But a real switch node where you can set any number of inputs would be great...just sayin...


Is there a delta transform for collection?

RIGHT-CLICK your collection in the outliner, Select Objects
Now you can move, rotate, scale, etc. all the objects together.
Or:
If all the objects you want to move together are the only ones visible, hit A to select all and move, rotate, scale, etc.


How is it possible, incorrect keyboard assignments

Do you have multiple languages on your computer?  I ran into this b/c I also have French on my computer and whenever I pressed alt+something (I never figured out what I pressed) it would change languages and so the keyboard would change and so would the shortcuts.  The way to fix this is to minimize Blender, go on the taskbar, bottom right, and see if there is a different language select.  If so, you've found your problem, just click on it and change it back.  If not, IDK.


As suggested in comments, you could simply hide it at animation start and reveal it at 150 keyframing its visibility.

To do this you can keyframe the domain object "eye" icon when it must change state (press the i key on it) in the graph editor you can edit this as usual but it will add a "restrict view" channel.

This can toggle visibility on/off by getting values of 0/1 (visible/invisible) as below:

which works like this


How to make particles of an object that is made of several arrayed objects?

So I had a quick player around with a scene I just made.

You have to make sure that the object (in my case plane) is in a sperate collection to the the lupin objects.

In the "Particle Properties" tab in the outliner toggle "Advanced" in Hair to get the some more options you might need.

Under the "Render" tab, switch "Render As" to Collection (which I believe you did). In the same options toggle "Whole Collection" in order for it to emit the whole lupin/object as one and not random segments.

In my case (you may not have to) Under the "Rotation" settings I had to change the "Orientation Axis" to Global Y, but have a play around with it, it may be different in your case.

Note You should play around with the "Hair Length" under emission tab in conjuncture with the "Scale" under the "Render" tab in particle properties to get the size you want.


They do move together, you just need to click or press enter to confirm and see the change.
If you want to see the mesh move in real time while you are moving it with the armature, disable Delay Refresh in the Display panel of your armature.


Mirror Causes Left Handed Local Transform

Turns out  the "problem" is that the scale was -1 after the mirror operator.   After applying scale, the coordinate system was right handed again.

-P


The problem is that you have too many control points on the curve, which makes it hard to control.

Would be best if you could fit a bezier or bspline curve to the shape of your curve with less control points.

You can control curve(s) with vertex hooks modifiers pointing to bones. Add an armature and make a bone in every curve's control vertex location. Select bone in posemode, shift-select curve, enter edit mode, select control vertex at bone's location (or multiple points if there are many in line), Ctrl+H+Make Hook to Pose Bone.

Then pose the bones so they are straight. You can parent them into a chain and position them by rotating the parents, so the curve points move naturally in an arch.

The more control points the more tedious it is. This process can be however scripted easily.


Merging an array of paths to be used as a curve deformer

Unless the paths are connected (not just joined together in a single object) the array will not extend past the original curve.
Convert the curve to mesh, and then apply the array (making sure the merge option is enabled) that will give you a mesh with the shape of the arrayed curve.
Then convert the mesh back to curve and the other array should work as you want.


Multiple materials with different textures

Not entirely sure what you mean. From the screenshot it looks like you have several meshes, one for each texture. What is "material display mode"? You can have different textures applied to the same mesh without splitting the mesh up like you have done. I think that might be what you need to do if you want them to show up all at once. Like this.

Edit: To explain a little better. Here The red material has no textures, the green material has one texture (cloud) and the blue material has two textures (cloud and noise) Hope that helps.


Parametric design for pen adapter for 3D printing

I understand your problem to be:
"How do I make this model parametric, so people don't need to change vertices in order to adapt it to their physiology"

Here I have a few pointers:

The question of the pen is probably the easiest solution: Create a mesh for a pen and use a boolien modifier to create the hole. Each grip can be scaled but the hole for the pencil will remain the same size.
Unless blender implements an node based modelling toolkit in the near future, your toolkit in order of ease to use consists of:

shape-keys Morph targets: A sphere shape turning into a cylindrical unwrapped sphere shape
boolean modifiers
scripts


As you said you've tried Ctrl+p, so the door is not a child of any object.
Then the only thing that can cause this problem is that the origin far away from the door. Select the door, press T > on left hand side menu set "Origin to Geometry".

If it still doesn't work, share the blender file with us or recreate the problem (if you can) in a separate project and share that file.


Strange flickering while modeling in Blender 2.8 beta

The flickering was because your Clip Start distance was way to small. This setting can be found in the View menu of the Properties side panel. The N key to toggle view or hide panel.

It was set at 0.00002m :

Increasing the distance a little to 0.1m .........


Try the following solutions

Maybe just because of the Smooth Shading applied for a low poly 3D model: Your model is currently at a low poly stage so change it into high res model or remove smooth shading until you add in more details to the model(maybe at least till you add subsurfs).
Normals Issue: Try recalculating the normals -> enter edit mode and select all then press Ctrl+N key
Duplicate Vertices or edges issue: Enter into edit mode and select all, then press W key and click on Remove doubles


How to display and use operator properties in a custom UI panel?

You can set new property like this:

bpy.types.Scene.my_use_x=bpy.props.BoolProperty()
row.prop(context.scene, 'my_use_x')

And set property of operator like this:

operator = row.operator("mesh.vertices_smooth")
operator.use_x = context.scene.my_use_x
operator.use_y = False
operator.factor = 2

I do not use blender 2.8 and I did not test this. But it should work.


GPU computation difference between rendering and cloth baking

Besides the OpenGL viewport preview, GPU Acceleration inside Blender can only be used currently for rendering with the Cycles Render Engine using either CUDA on NVidia GPUs or OpenCL for AMD Graphics cards on certain supported hardware. OpenCL acceleration may also be used on the compositor for image processing.

Physics baking, particles and cloth simulation and all other areas currently only use CPU, as far as I know.


Limit selection to visible not working in orthographic perspective

I reduced the clipping distance down from 1000000 to the default 1000 and scaled down the model and it solved the problem.


How do I get pixel by pixel depth data out of a .exr file?

Enable the Z buffer on the output settings:

To check if the Z buffer is correctly rendered, you can load the OpenEXR file in the compositor and add a normalize node to visualize the Z-channel:


Why is my face orientation moving while I orbit an object and how do I fix it?

Your clipping distance starts very low, and Blender doesn't like it :).

Either increase the Clip Start distance in SideBar > View
or switch to Orthographic view through View > Orthographic

Increase the Clip Start distance...

...or switch to Orthographic view


Why are my ocean/glass shaders not being rendered properly?

I just accidentally found out, i was having a not-displayed older object lying beneath the other object and intersecting at some areas.


Track object and draw path on top of video

Track your object in the Movie Clip Editor

Select the tracker and in the solve section select Link empty to track.

Switch to the the regular 3d view. Through the camera biew you'll see an empty that behaves like the tracker.

(I added the video image as background for clarity, but is not necessary)

Select the empty and snap the cursor to the empty (Ctrl+S and select Cursor to selected)

Add a Curve > Bezier object.

I edit mode (Tab) select the end control point of the curve, and snap it to the cursor, that will move the end of the curve to the empty.

Exit edit mode.

Select the Empty and while pressing shift select the curve. And enter edit mode (this is done so that the Empty becomes the target object for the next operation)

Press the space bar, type "hook" and select "Hook to Selected object".

That will make the end of the curve follow the empty.

Go to the first frame of the video (or where the movement begins), and snap the cursor to the empty (Shift S > snap cursor to selected). Don't worry if the other segment seems to unhook from the empty momentarily

Then select the curve, enter edit mode, select the first segment of the curve and snap it to the empty (snap selection to cursor). (don't worry if the other segment seems to unhook from the empty momentraily)

Note that the curve will track the beginning and end points but not necessarily curve along the way... you might need to adjust that manually.


Why does the same material look different on another object?

The procedural Brick texture in the 'WO_Wood Texture' node group has no vector input connected to it so it uses 'Generated' texture space that maps the texture's x y z values to the bounding box of the object so it depends on the size and orientation of the object - if you rotated the object and applied rotation (ctrl+a) you would see the texture change its orientation. To solve the issue you need to use texture space that is uniform in size. You could use 'Object' space and it would be the same size for objects with the same scale, but you would need to match orientation by applying it while the object rotation is aligned to the texture and then rotating it back to the way it needs to be in the scene. My recommendation however would be to use UV texture space and match the sizes and orientation of your UV maps:


How to adjust operator settings after leaving the settings panel

Unfortunately, you can't. Once you perform another operation, the changes are set.

However, the operator should retain its last-used settings; you can delete the knot and re-add it, then change the settings to suit your liking.

If you want to change the settings before doing anything else, you can use the panel in the Tool Shelf, or press F6 in the 3D View to bring up the options for the last-used operator.


I think these are face sets, as explained here by Blender Guru, they are a kind of masks that you can create in Sculpt mode in order to delimit certain areas:

To remove the face sets you can select the tool again, Ctrl left click on a grey area and paint on the colored areas. Or you can simply deactivate the option in the Viewport Overlays panel:


Saving startup file does not effect startup

I believe it's a bug of blender I reported here, which already fixed in the current development branch and will be backported to 2.83 LTS version (fix included in version >= 2.83.4). For a workaround, after you do save your startup file, then navigate to preferences dialog and do any setting to get userpref.blend file generated in the blender user config folder, then it should works.


Most likely the issue is that you have two different curves in the SVG file and they got imported as different objects, so they are filled differently.

In edit mode select both curves (select one first and then press shift and select the other) and join them pressing CtrlJ

Now the fill should work fine:


Why is one of my objects is not visible in the final rendering?

you can check if relevant objects are enabled/disabled in render.
I usually prefer to show it in outliner like this:

click on filter icon and activate the button with camera icon

then you can see it in outliner and check if object is enabled/disabled for rendering

and since you are using modifiers you should check if render is enabled for modifier too (it is always the camera icon)


prevent add-on being enabled in lower Blender version than 2.8

Blender 2.80 already protects against enabling incompatible add-ons. If the Blender version in the bl_info is too low, it will display a warning in the preferences. Blender will not run the register() function on these add-ons. However it does allow to tick the checkbox and the user may get the impression that it's properly enabled.

If you want to avoid that, you can check the Blender version and raise an exception in your __init__.py. This will prevent the checkbox from being enabled and the user gets an error message right away. I'm not sure if it will have the intended effect, since some users may not read or understand the error message.

bl_info = {
    "name": "Version Check Add-on",
    "author": "Robert Guetzkow",
    "version": (1, 0),
    "blender": (2, 79, 0),
    "location": "View3D > Sidebar > My own addon",
    "description": "Checks if the correct version of Blender is used",
    "warning": "",
    "wiki_url": "",
    "category": "3D View"}

import bpy

if bpy.app.version > (2, 79, 0):
    raise Exception("This add-on is incompatible with Blender versions newer than 2.79.\n"
                    "For Blender 2.8 please download the version from the following link:\n"
                    "[insert link here]")

class EXAMPLE_PT_panel(bpy.types.Panel):
    bl_label = "My own addon"
    bl_category = "Name of your tab"
    bl_space_type = "VIEW_3D"
    bl_region_type = "TOOLS"

    def draw(self, context):
        layout = self.layout
        layout.label("Congratulations, your Blender version is supported.")

classes = (EXAMPLE_PT_panel,)

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

def unregister():
    for cls in classes:
        bpy.utils.unregister_class(cls)

if __name__ == "__main__":
    register()


How to rotate or snap object parallel to specific face of another object?

As @Sanbaldo mentioned in comment section, we can use Measurement tool to determine angle between faces and rotate source detail.

In more complex situation this answer is available to solve this task:
https://blender.stackexchange.com/a/156469/87633

Thanks to @JachymMichal


What you need to do, is remove doubles. You have 36 doubled vertices in your model, and that is what is giving you problems it seems. After doing this, bevel gives no issues. Tab into edit mode, then select all, and press W>remove doubles.
Then proceed to bevel, and you shouldn't have any problems.


How do I export an object from blender to Unreal Engine 4 correctly?

You save your model as Obj or Fbx and import it to your scene. Fbx is more practical for rigged models and I would suggest that you use the TGA file type for textured meshes.


From the problem you described. I have a few suggestions.
To "apply the scale but keep it as it is":

On your duplicated eye. Press CtrlA then apply "Rotation & Scale". The reason for rotation is because scale would not make it flip, but rotation might.


Control object emission strength (not material)

The simplest for me would be to use the object pass-index.
This is supposed to be used in the compositor workspace but the value can be accessed in the shader editor. It is an integer value so if you want more precision, you can add a math node set to divide between the "Object Info" node and the "Emission" node.


How to make the camera follow an object's trajectory in 2.8?

Give your object a Copy Location constraint with your object as Target, click on the Offset option so that you can still move your camera the way you want.


Why does a rigid body with Convex Hull collision bounds not move in BGE?

Enable Physics at your material.

Hints (outside of the question):

You named your objects and bricks - I like that. It was really helpful when looking at the scene.
The meshes have way too much faces for a game. They do not need that many for that little detail. I strongly suggest to remove the subsurf modifier(s). You can use smooth shading instead.
The floor creates projectiles. This was really distracting when analyzing your file. I would not expect a floor to behave this way. A separate object (e.g. called RandomProjectileSpawner) could do that job. You can add/remove it without loosing the scene's floor. You could even have more than one.
The dimensions of the projectile's physics shapes are way too large. They collide with the physics mesh of object Ship right after creation. I suggest to enable collision bounds at the physics tab on the projectiles. A box shape should be good enough.
Be aware the physics engine has problems with small travelling objects. It might happen that they do not collide with another face and suddenly are inside of an object, or that a collision does not get registered.

I hope it helps


Object Info returns 0. Random materials for different objects

I found the mistake myself. The object info values are only applied once the scene gets rendered. Therefore I could not see any changes myself in the editor.


Can I export to .stl without selecting items (export everything)?

You cannot export .stl files without selecting at least one object.
My suggestion to you is dot not use box select objects by pressing 'B'

To select all object just hit 'A' , to deselect all hit 'A' again


Randomize the UV of an object with an array modifier?

Try V-Offset/V-Offset in Array Modifier.


Each UVmap always contains the UV coordinates of all the object's faces.

If the material is the same for each face, I would suggest to make 1 material with 1 big texture that contains all 6 individual textures. Each face's UV island should cover to only a portion of the UV layout as it's done in this related answer https://blender.stackexchange.com/a/28349/15140

This is just one of the possible UV layouts. Sometimes can be useful to have a 3x2 matrix of images and using a rectangular texture... it dependes on your needs.


means that that layer does not participate in rendering. This option is useful when you need to do separate renderings (different renderlayer) to merge then compositing