Problem with selecting faces vertices edges and texturing

Ok. I think I fixed it. What I did was delete the light (so I could select all and only get mesh parts). In object mode, I selected all, and right click > join to make it all one piece (one mesh). I tried the CTRL+J method a couple of times first, so you might have to fiddle with it -  I don't know why it didn't work until I used the right click method. Anyway, once it was all joined into a mesh, I went to edit mode, then select all > mesh > clean up > merge by distance - because there are "seams" between the edge pieces. I counted 1160 vertices removed. After that, I had to UV unwrap again because there were overlaps, but I think it's good to go. If, in the future, you need it to be more pieces, you can always separate it later.
I'll upload a copy of the file I modified for reference.
Here it is -
Hope this helps.
EDIT - Here is your file "cleaned up" it still is not perfect - I did a quick and messy job on the UV unwrap just so I could get the textures to look decent - you may have to redo them. Also, many of the floors are still n-gons, this might not matter, but if you want to triangulate for a game engine later, you might want to make sure it's all quads first to be sure there a re no issues. I separated what "chunks" of floor looked appropriate, but obviousely, you will want to divide some of them on your own for texturing reasons - i'll leave that to you. I also have to remove your texture in order to pack the ones I used, you'll have to replace it.
Here is the (cleaned up) file.  Hope this finally works for you.


If you have a face on the edge perpendicular to the front face, then you can select the face and move the view with ShiftNumPad 1. That will rotate the view so that the edge is alined, then the angle constraint in the knife tool will work.


Make a Low-Poly Object with an equal balanced number of Vertices

For redistributing the verts try the remesh modifier.

To make your model look more like the picture you posted, you have to lower your polycount, which you can do by editing parameters in the remesh modifier I mentioned or by retopologizing manually.

As for good low poly modeling, there are plenty of tutorials, and that's not something I can answer here. It'll take practice and patience, as low poly is harder than it looks.

For texturing, since it's done on a face-by-face basis, do not use UVs or textures, but instead use multiple materials and assign different materials to different faces.

Lighting like that is decently simple. Flat shading, a directional light, and some global illumination. If you're using Unity, also look into the image effects standard assets, like screen space ambient occlusion or color correction. After that, just iterate.


I think it is meant to be something like
row.operator("render.render", text="Render Animation", icon='RENDER_ANIMATION').animation = True


I downloaded the OBJ file and imported it, and sure enough;

I've seen this issue before. I don't know if it's the default in blender, but my "Clip Start" value was incredibly small (0.01m). I changed it to 1m, and the model looks fine now;

Edit: It's also worth noting that this model is massive. I scaled it WAY down to work with it originally. However, I started with a fresh file, imported it, and the following settings work with the original scaling;

The "Clip start" was making the surface look weird. The "Clip end" was cutting off the back of the model.


How do I programmatically determine if an object is a 'linked duplicate' of another?

Object.data
Linked duplicates will have the same linked data, if there is linked data.  For an empty ob.data is None
import bpy
from collections import defaultdict

scene = bpy.context.scene

data_links = defaultdict(list)
for ob in scene.objects:
    data_links[ob.data].append(ob)

for k, v in data_links.items():
    print(k, v)

Sample output,  notice there are 4 objects using the mesh "Cube.001"
<bpy_struct, Mesh("Cube.001")> [bpy.data.objects['Cube'], bpy.data.objects['Cube.001'], bpy.data.objects['Cube.002'], bpy.data.objects['Cube.003']]
<bpy_struct, PointLight("Lamp")> [bpy.data.objects['Lamp']]
<bpy_struct, Camera("Camera")> [bpy.data.objects['Camera']]
None [bpy.data.objects['Empty'], bpy.data.objects['Field']]


I expand my comments above, to post some example image. I still think it's a matter of mesh density:

To better visually describe I exagerated size of the diff meshes, but this is the overall setup:

this is how a subdiv level of 2 on a standard UV sphere, in boolean diff with a cube, enough subdivided and extruded, then hidden. Still, you see some artifact on the hole edge.

I tried a gif animation showing the effect of changing settings, but due to color banding it gets lost... so here is a rendered comparison with subdiv 0,1,2, and 4 (enough in this example)

As said above I can't show you here, but even "moving around" the sphere doesn't show artifacts (or they are much more subtle) in the viewport, and the same goes in the render.

I don't know how better you can solve this, but using much higher resolution on the edges of the subctraction, at least, will help blender to find a "smooth" setup for normals of geometry around that area...


Try installing a proper media player software like VLC, MPC-HC, MPC-BE or Potplayer

Also for future reference it is always advised to render animations to image sequences, never directly to video file formats


Watertight surfaces can't be unwrapped in one time without seams

The issue comes from the absence of any seam in the portion of mesh that not belong to the pool's stairs. As there is no edge marked as seam, you are asking the software to unwrap a shape that is "solid", that cannot be profitably unwrapped, an operation that leads to the "default" result (the same you get when choosing the reset function).

That is true even for simple object like the shown pyramid. You simply cannot unwrap watertight mesh (unless the are bi-dimensional): you need at least to make an hole somewhere or, preferrably, mark some seams:

Here's a possible result using the provided mesh:

Seams has been made all around the floor of the pool (on both sides) and the resulting ring has been cut in half at some point.


How to create list bullets in an operator's class description? (see example)

Tool description
The bulleted list is a description of the measureit ruler tool, the source of which can be found in startup/bl_ui/space_toolsystem_toolbar.py
@ToolDef.from_fn
def ruler():
    def description(_context, _item, km):
        if km is not None:
            kmi_add = km.keymap_items.find_from_operator("view3d.ruler_add")
            kmi_remove = km.keymap_items.find_from_operator("view3d.ruler_remove")
        else:
            kmi_add = None
            kmi_remove = None
        return tip_(
            "Measure distance and angles.\n"
            "\u2022 %s anywhere for new measurement.\n"
            "\u2022 Drag ruler segment to measure an angle.\n"
            "\u2022 %s to remove the active ruler.\n"
            "\u2022 Ctrl while dragging to snap.\n"
            "\u2022 Shift while dragging to measure surface thickness"
        ) % (
            kmi_to_string_or_none(kmi_add),
            kmi_to_string_or_none(kmi_remove),
        )
    return dict(
        idname="builtin.measure",
        label="Measure",
        description=description,
        icon="ops.view3d.ruler",
        widget="VIEW3D_GGT_ruler",
        keymap="3D View Tool: Measure",
    )

The bullet is character \u2022.  The associated shortcuts are gleaned from the respective keymaps.
Operator description classmethod.
Find link

Operators can now have multi line tooltips. Here I've put the above description into the simple operator template
class SimpleOperator(bpy.types.Operator):
    bl_idname = "object.simple_operator"
    bl_label = "Simple Object Operator"

    @classmethod
    def description(cls, context, event):
        return (
                "Measure distance and angles.\n"
                "\u2022 %s anywhere for new measurement.\n"
                "\u2022 Drag ruler segment to measure an angle.\n"
                "\u2022 %s to remove the active ruler.\n"
                "\u2022 Ctrl while dragging to snap.\n"
                "\u2022 Shift while dragging to measure surface thickness"
                ) % ("Foo", "Bar")

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


How do I make a face swap animated character in Blender?

There are multiple ways to do this.

Assuming your three faces share topology, the simplest is to join them as shapekeys to a base version of your mouth, and animate the shapekeys with constant interpolation instead of bezier handles.

If you need to use multiple models, you can control the visibility of a mesh using drivers, driving either Cycles settings or material transparency.  Because Cycles doesn't handle coincident meshes well, even transparent coincident meshes, you may have to combine this with simple shapekeys that shrink the hidden meshes.  Again, you will want to animate with constant interpolation-- you don't want to fade in and out, and you want hard switches.

Your drivers should probably all use the same ultimate control.  A good example would be via a bone, where you set the mix node between a regular shader and a transparency shader based on, say, the global Z position of a particular bone, and you set the expression to be (var>= 1.0) and (var <2.0) .  That way, you make sure that you're never showing two meshes at the same time.


how to create fake reflections on objects?

So when you have created your shape in Illustrator or whatever application you use for SVG.

You create a new scene in Blender, delete the cube and put the render engin to Cycles

After, just import your svg file

You should have your tiny svg file appearing in the scene, select all parts that will have the same material (Shift + B) and join them

Go to your material panel and click on use nodes

To ease the process, change the viewport color to white

We're ready to work on the extrusion and the bevel, so go to the curve panel and play with the settings to have something that suits you.

Now the material part, go to the node editor

And add (Maj + A) a Glossy Shader, a Mix Shader connect everything as the image below

Time to add some light, create 2 planes, that you'll place in order to have good reflections, you'll have to play a little bit with it so the render suits you

The we are going to create the material for the planes, so go back to the node editor and create a Emission shader, set the strength to 15

And last but not least, the glowing corner. Select the part that you didn't join during the first steps, and create a node setup as this one

Set the camera and hit render, you should get something like this:

It is not perfect, but with some tryouts, and a little bit of compositing you should reach a good result.


Custom search data to UILayout.prop_search

Use a pointer property with a poll.
To distinguish a regular material from one for a gp object there is the handy attribute Material.is_grease_pencil
Similarly to https://blender.stackexchange.com/a/159155/15543 and using a poll method https://blender.stackexchange.com/a/101303/15543
Will narrow down the selection based and offer the same choices as the regular material drop down.
import bpy
from bpy.props import PointerProperty

def poll_material(self, material):
    return not material.is_grease_pencil

class TEST_PT_layout_panel(bpy.types.Panel):
    bl_label = "Prop Panels"
    bl_category = "Test Panel"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "scene"

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

        col = layout.column()
        col.prop_search(scene, "prop", bpy.data, "materials")
        #or
        col.prop(scene, "prop")

def register():
    bpy.types.Scene.prop = PointerProperty(
        type=bpy.types.Material,
        poll=poll_material,
        )
    bpy.utils.register_class(TEST_PT_layout_panel)

def unregister():
    bpy.utils.unregister_class(TEST_PT_layout_panel)
    del bpy.types.Scene.prop

if __name__ == "__main__":
    register()

Kinda related:
How to populate UIList with all material slot in scene? 2.8


Incorrect matrix_world after transformation

Note for those using blender 2.8x: scene.update() has been removed as of 2.80. Use bpy.context.view_layer.update() instead, as per this post.


Motion Blur problems with wheels and Rigacar

The issue appears to be with the way that I created my instances. The origins of the instances of the wheels are at the center of the instances making them move smoothly in the viewport. However, the source of the instances has the origin of the tire set not at the center of the wheel.
To fix the problem: I applied all the modifiers on the tire tread and centered the tire's origin.
I also had to rebuild parts of the scene and the following paths in order to implement the new instances.


Reverting shifts and rotations to an imported object

For reverting, the information you're missing is the exact location of the origin, before it was moved.

If you can find it (maybe reimporting the mesh, and pressing Shift S - cursor to selected) it should be simple to perform a "backflip" (just use negative values for the trasforms)


Shaping Bezier objects and applying Physics collisions?

Apparently you can have soft body physics on Bezier Curve Objects as detailed on the Quick Noodle Physics in Blender Tutorial Youtube Video

According to the video the trick is using a highly subdivided curve, there must be lots of actual vertex (display subdivisions are insufficient), many of the settings are ignored.

You should turn off Soft Body Goal, and tweak the parameters under Soft Body Self Collision like Ball Size and Stiffness.

Some other object set to Collision Physics type must be present at the scene for interaction.

Also see related Are curve physics possible?


Ok so, what you have to do is tell the shader where to draw your logo and where to draw the metallic part. If your lid is uv-unwrapped you can manipulate the uv coordinates to do it. Provided you have a png with an alpha channel this is quite easy. This is my setup :

Basically you take the uv coordinate and pass it through a mapping node to tweak the scale and position of your uvs. Then plug it to the image texture node and remember to set it to clip so that it doesn't repeat. Plug the alpha in the factor input of a mix shader and plug in the top input your metallic shader and in the bottom one your logo shader.
Then tweak the mapping node as you wish.


Using Custom Properties (ID properties) works:

for key, key_type in props.items():
    context.active_object[MinkoScript.format_property_name(i, key)] = script.get_property_default_value(key)

In order to be able to iterate on a specific script properties to draw the panel, I also store the properties dict in an ID property:

context.active_object[MinkoScript.format_property_name(i, '$properties')] = props

Then in the panel:

for i in range(0, context.active_object['minko_num_scripts']):
    layout.label(
        context.active_object[MinkoScript.format_property_name(i, '$name')] + ':',
        icon='TEXT'
    )
    box = layout.box()
    script_id = 'minko_script_' + str(i)
    script_props = context.active_object[MinkoScript.format_property_name(i, '$properties')]
    keys = sorted(script_props.keys())
    for key in keys:
        row = box.row(True)
        col = row.column(True)
        col.label(key + ':')
        col = row.column(True)
        col.prop(
            context.active_object,
            '["' + MinkoScript.format_property_name(i, key) + '"]',
            text=''
        )
    row = box.row(True)
    row.operator(MinkoRemoveScriptOperator.bl_idname, text="Remove").script_id = i
    row.operator(MinkoReloadScriptOperator.bl_idname, text="Reload").script_id = i


You have to check "Tab for Pie Menu" box in Preferences>Keymap


Remove all zero vert mesh objects from scene.
Script below will remove all zero vert mesh objects from the scene.  For your use case could instead look only over context.selected_objects.
import bpy
scene = bpy.context.scene

empty_meshobs = [o for o in scene.objects
                 if o.type == 'MESH'
                 and not o.data.vertices]

while empty_meshobs:
    bpy.data.objects.remove(empty_meshobs.pop())

Another alternative is to not split if the selected vertices are all of total.
sel_verts, _, _ =   context.object.data.count_selected_items()
if sel_verts < len(context.object.data.vertices):
    bpy.ops.mesh.separate(type='SELECTED')


The easiest way to do this is the Curve modifier.

In the following screenshot you can see a torus mesh to which I added an Array modifier and a Curve modifier.  The curve modifier refers to the Bezier curve.

I had to rotate the torus array 90 degrees around the Y axis because it seems the curve array defaults ton the X axis.  I guess I could have picked a different deformation axis if I had noticed that radio button array earlier.


Set active collection by selected object Blender 2.83

With J key in Outliner or in View in Object Mode it switch collection to active by selected object.
It can't be implemented as always on, because you can't change active collection then, it will be always related to active object which in some cases problems.
    # ##### BEGIN GPL LICENSE BLOCK #####
    #
    #  This program is free software; you can redistribute it and/or
    #  modify it under the terms of the GNU General Public License
    #  as published by the Free Software Foundation; either version 2
    #  of the License, or (at your option) any later version.
    #
    #  This program is distributed in the hope that it will be useful,
    #  but WITHOUT ANY WARRANTY; without even the implied warranty of
    #  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    #  GNU General Public License for more details.
    #
    #  You should have received a copy of the GNU General Public License
    #  along with this program; if not, write to the Free Software Foundation,
    #  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
    #
    # ##### END GPL LICENSE BLOCK #####

    import bpy
    bl_info = {
        "name": "Switch Active Collection",
        "location": "3D View / Outliner, (Hotkey J)",
        "version": (0, 1, 0),
        "blender": (2, 90, 0),
        "description": "Switching active Collection to active Object selected",
        "author": "APEC",
        "category": "Object",
    }

    #Recursivly transverse layer_collection for a particular name
    def recurLayerCollection(layerColl, collName):
        found = None
        if (layerColl.name == collName):
            return layerColl
        for layer in layerColl.children:
            found = recurLayerCollection(layer, collName)
            if found:
                return found

    class OUTLINER_OT_switch_collection(bpy.types.Operator):
        bl_idname = "outliner.switch_collection"
        bl_label = "Switch Collection"
        bl_options = {'REGISTER', 'UNDO'}

        @classmethod
        def poll(self, context):
            ar = context.screen.areas
            __class__.area = next(
                (a for a in ar if a.type == 'OUTLINER'), None)
            return __class__.area

        def execute(self, context):
            obj = bpy.context.object
            ucol = obj.users_collection

            #Switching active Collection to active Object selected
            for i in ucol:
                layer_collection = bpy.context.view_layer.layer_collection
                layerColl = recurLayerCollection(layer_collection, i.name)
                bpy.context.view_layer.active_layer_collection = layerColl
            return {'FINISHED'}

    addon_keymaps = []

    def register():
        bpy.utils.register_class(OUTLINER_OT_switch_collection)
        wm = bpy.context.window_manager
        kc = wm.keyconfigs.addon.keymaps
        km = kc.get("Object Mode")
        if not km:
            km = kc.new("Object Mode")
        kmi = km.keymap_items.new("outliner.switch_collection", "J", "PRESS")
        addon_keymaps.append((km, kmi))

        km = kc.get("Outliner")
        if not km:
            km = kc.new("Outliner", space_type="OUTLINER")
        kmi = km.keymap_items.new("outliner.switch_collection", "J", "PRESS")
        addon_keymaps.append((km, kmi))

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

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


In these situations I like to delete the edge and use F2 add-on for reconstructing the geometry(F2 comes with Blender and just needs to be activated in the Preferences). I have it enabled anyway for modeling and this process is quite pleasant because of the simplicity of it - only pressing f a few times:


Toon material present some kind of deformation, jagged, spike noise

The problem is caused by the geometry at the pole of the UV Sphere interacting with the Smooth Shading to produce artifacts in the generated Normal as described in this question and its associated answers : How to avoid the wrinkle at the poles of the UV sphere?

The UV Sphere consists of edges formed from the Latitudinal lines (those around the sphere) and the Longitudinal lines (those going north to south). The Longitudinal lines all converge at the poles and this creates a number of long thin triangle faces as shown :

The problem is that slight inaccuracies in the smooth shading of each adjacent face is resulting in noticeable artifacts in your toon shader.

You can avoid this problem by changing the geometry to avoid such long thin triangular faces. The attached answers provide some methods of achieving this but an alternative is to use an Ico Sphere in place of a UV Sphere.

The geometry of an Ico Sphere is made up by subdividing an Icosahedron (a 20-sided regular mesh) such that each face is an equilateral triangle. As there is no 'pole' to provide difficult geometry you should no longer get the issue.

Once you have created the Ico Sphere you can adjust the number of sub-divisions to determine the level of detail.

Setting the mesh to Smooth Shading should produce a consistently smooth sphere.

For the shadows you could simply use the Shadow output of the existing Lamp Data node as the factor to a MixRGB node set to Multiply by a light grey (vary the intensity of this grey to affect the density of the shadow) as shown :


Where is "Film" setting to allow rendering transparent background?

You have to be in cycles render, then look to the render propreties tab


How do you scale both sides in axis Z while the other side is less affected?

If you're referring to creating this effect with a mesh, you could use an array with a custom object offset, like in this blend here:

All you need is a Plane (Or Cube) plus an empty. The empty should be created at the origin of the Cube to easily understand how the effect works. Then, add an array modifier to the cube.

Instead of using the Relative Offset, which is the default, you can use the object offset and choose the Empty. Now, each element of the array receives the Transform differences between the cube and the empty. Move the empty to the side a bit, and you'll see what it means. If you now scale the empty only in the Z direction, you get the effect which (I think) you want. Each array element is a scaled down version of the element before. So the first one has Z = 0.9, the second one Z = 0.9 * 0.9, and so on.

To put it on a circle, use 'Simple Deform' or curve modifiers, whatever works best for you.


Issue with grid and Blender Unit (Screenshot attached)

Try setting the unit scale to .001. The drop down settings only affect what prefix is used to display the units, not the actual scaling.


Problem with Curve Modifier on object array

Curve modifier needs a subdivided,  the more the better, mesh to work as expected. Instead, use Bevel object which is a bezier circle with handles set to vector to form a square. Then rotate it and make a rectangle.


This happens when you don't check ✓ Use Nodes in the Compositor.
In such case, only the Render Layer will be composited, as you described.


This is because it is not a perfect sphere, it is constructed of flat faces and it is not perfectly symmetrical. ( could have a vertex at the top and a flat face at the bottom), to get it  close to the dimensions you want increase the resolution of the sphere (segments and rings ).

just consider a simple case of a circle since it is made of finite straight lines its dimension wouldn't be as expected depending on its resolution :

you can clearly see why X differ from Y for this circle.


Why does the frame around the camera flicker while running the BGE embedded player?

I quess this has something to do with the transparency of the area out of the camera region. By trial and error, I figured out that the flicker dissapears when you set the passepartout to 1.0.

However, in my case some of the text objects in the UI still flicker.


Displacement moves my mesh away from it's position in Render Mode

You should plug the noise texture output into the "Height" input of a displacement node, then plug the output of this node into the displacement input of the "Material output" node.


Well, turns out that the smoke-cache, (and other "cache bakes"), are actually stored in the .blend, if not set to bake externally. I tested this by baking a smoke sim, then stopping it at frame 40. I exited Blender, then loaded the file again. All the information for the smoke was still there.


Why does Joining objects together stretch UV mapping for some individual faces?

I've figured it out, Selecting the object and pressing CTRL+A in 'Object Mode' then applying  the scale fixed it.

(credit to @Paul Gonet)


Reset object origin without moving object

Here's one way which assumes your object is centered over 0,0,0:

Snap the 3D cursor to the object's origin (⇧ ShiftS)
Depending on the orientation of your object, set the 3D cursor's location to 0 along one axis (based on your screenshot you'll want to set it to 0 on the Y axis)
Snap the origin to the cursor (⎈ Ctrl⇧ Shift⎇ AltC)

Apply rotation (⎈ CtrlA) to vertices (this will reset object rotation).


Blender 2.77 Bsurfaces add-on works with "d" key in Mac version but not on PC version

I found a work around for the issue with the NX500 Zenbook from Asus not working properly with Blender when using the "d" key to draw with the touch pad.  It works by just using the touch screen.


How can I deactivate all the materials before rendering in Cycles?

You can assign a single material to the whole layer. The original materials will remain assigned to your objects but will be ignored at render time and will be replaced by the material specified on this setting.


Can we render a sky layer with transparent layers?

The easiest solution to this is to do a third render without any visible objects and Alpha set to Sky in the shading properties in the render menu. Once that's done, alpha over your sky background just like you have done already between the two scenes.


The current screen you are in has context.  A screen is made up of a number of areas.  Each has a "space".

The property panel displaying the clipping is in the 3d view space its context area type is VIEW_3D

The console has its own area and space types, pertinent to (... in the context of ...) running script in the console. There is no clipping or view angle etc needed for the console, it displays text and runs code.

Hence the error, the python console space has no clipping distance.

As an example,  I have a screen with 4 areas open, the 3d view, the python console, properties and the outliner.  as Illustrated below with python console code

I am interested in the view 3d area, and see that it is index 3 of all my screen areas.

Once I have the area of the right type the space is area.spaces.active .. (often seen as area.spaces[0] I prefer the former) to which I can set the clipping distance.

See docs.  https://docs.blender.org/api/master/bpy.types.SpaceView3D.html#bpy.types.SpaceView3D.clip_end

Notice how the space of a 3d view is type SpaceView3D

>>> for i, a in enumerate(C.screen.areas):
...     i, a.type
...
(0, 'PROPERTIES')
(1, 'CONSOLE')
(2, 'OUTLINER')
(3, 'VIEW_3D')

>>> v3d_area = C.screen.areas[3]
>>> space_data = v3d_area.spaces.active
>>> space_data.clip_
                    end
                    start
>>> space_data.clip_end = 1
>>>

If I write an operator or panel to be displayed in the 3d view, then the space would be in context and I could simply use

space_data = context.space_data


glitch on my meshes (Except wireframe mode)

I suspect the usual problem where you set extreme ranges in the Clip Start/End values. Try to keep the Start Value to be at least a 1/10000 of the End value.


Irregular mask size compositor vs movie clip editor

Your mask node indicates 'Scene Size' and your scene is set to 50% of the render settings. Try adjusting this to either 100% of the render settings (if they match the image size) or choosing 'Fixed' and setting the actual pixels in X and Y axis.


You can go to User preferences > Input and set Presets(drop down menu to the top left and another one to right) to Maya.

It's been a long time since I've used Unity, but I think Unity and Maya are very similar in this aspect.

If Maya is not similar, try the 3DsMax preset.


If you want a glare with lines it is easy to do in the compositor.

In your scene add an object and give it an emission shader and use a strength that is more than 1.

Then in the compositor add a glare node in streaks mode. Use the threshold value to determine what values get affected by the glare node (in this example any value larger than 1 will be affected by the glare, darker values will remain unaffected). You can also choose the number of streaks you want:

(click on the image to enlarge)

Now, if what you want is to have is a more realistic "fog" effect, you need an environment (or a domain) with volume scatter. If you use volume scatter as volume for the world, then you can create real volumetrics, in which the suspended particles get lit by the light source and the mesh will create shadows (be ready to increase the strength of your light sources). Think of volume scatter as filling the scene with dust or smoke, the density for volume scatter will determine how hazy it is, usually the default value of 1 is way too high.

(click on the image to enlarge)

And don't forget that you can combine volume scatter with a glare node in the compositor as well:


Is it possible to alternate between the two colors in the Brick Node without any in-between shades?

Rather than connecting the brick texture to the colour input of your shader, you can use it to define the mix factor of different colours. With this approach you can use a colour ramp node to adjust the shading of the brick texture so you get less variation in the colour.

By connecting the fac of the brick node into a colour ramp you easily get a choice between brick and mortar (assuming you have a mortar size)

Then connect the colour output to a colour ramp that is set to constant interpolation and adjust the positions until you get a variation you are happy with.

Connecting the black and white colour from the colour ramps into the fac of the mix nodes lets you choose which colour is used.

Which leaves you with two brick colours and a mortar colour.


Ruler doesn't start from mouse & scale on object & pose mode is different

Using Ruler /Protractor

Ctrl+Left Mouse Button (will snap the start point) and Hold ctrl and drag

It snap to the edges


Select the faces ( if it's a loose part ctrl+L ) > spacebar > shade smooth

edit:
In the latest blender defaults F3  is the search feature instead of spacebar .

Alternatively select an
object > w > shade smooth


How do I mirgrate all image textures to a different folder?

If you don't have many Wavefront materials and you are copying all images from the same location to another location (also same for all pictures), open the .mtl file and replace all texture paths manually. You can try to speed this process up by using well-placed replace commands.

Otherwise, you'll need to write a script that reads all the path and edits them manually.

Read the file line-wise
Split each line by space. The first sub string will be the command
on "map_kd" and other map commands, read the rest of the string a path.
Edit the path. In Java you move a path path from path from to path to with the following code: to.resolve(from.toAbsolutePath().relativize(path));
Overwrite the line

You can also import the file as is if the program you used for importing supports moving source files.

And don't forget:

Always back up your files!


Why doesn't Blender have groups that allow you to transform grouped objects all at once?

To achieve what you want to do, simply right click on a collection and press "Select Objects", effectively selecting every single object in said collection, then transform however you like.


Assumption:

The speedometer does not move or rotate. It stays at the same place in scene.

Design:

Animate an invisible object (axis) that turns according to the input values.

Parent a visible indicator (needle) to the axis. Enable slow parent (Properties editor / object tab / Relation Extras panel) with an offset > 0.

Effect:

while the axis immediately shows the received value the needle will smoothly go for that pose.


Well, blender.stackexchange focuses around usage oriented questions, specific tasks etc, not opinion based, open questions about the market place.

But the answer is: Yes, there are people doing that. At the Blender Conference 2018 was a talk from someone working at Lucasfilm:

https://www.youtube.com/watch?v=UpcKPJTmqSI
(Blender Workflow for Feature Films - Jama Jurabaev)

Grease Pencil is a beast.

https://blenderartists.org/ might be a better place to have a discussion


How to keep a custom gizmo at the same place while changing is value?

Find my answer. Now the gizmo is comming back it's origin:

# Example of a group that edits a single property
# using the predefined gizmo arrow.
#
# Usage: Select a light in the 3D view and drag the arrow at it's rear
# to change it's energy value.
#
import bpy
from bpy.types import (
    GizmoGroup,
)
from mathutils import (
    Matrix,
    Vector,
    )

class MyLightWidgetGroup(GizmoGroup):
    bl_idname = "OBJECT_GGT_light_test"
    bl_label = "Test Light Widget"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'WINDOW'
    bl_options = {'3D', 'PERSISTENT'}

    @classmethod
    def poll(cls, context):
        ob = context.object
        return (ob and ob.type == 'LIGHT')

    def setup(self, context):
        # Arrow gizmo has one 'offset' property we can assign to the light energy.
        ob = context.object
        mpr = self.gizmos.new("GIZMO_GT_arrow_3d")
        mpr.target_set_prop("offset", ob.data, "energy")
        mpr.matrix_basis = ob.matrix_world.normalized()
        mpr.draw_style = 'BOX'

        mpr.color = 1.0, 0.5, 0.0
        mpr.alpha = 0.5

        mpr.color_highlight = 1.0, 0.5, 1.0
        mpr.alpha_highlight = 0.5

        self.energy_widget = mpr

    def refresh(self, context):
        ob = context.object
        mpr = self.energy_widget
        mpr.matrix_basis = ob.matrix_world.normalized()
        mpr.matrix_basis.col[3][2] = -mpr.target_get_value("offset")

bpy.utils.register_class(MyLightWidgetGroup)


Export armature DAE -> glTF rotates mesh 90 degrees

The solution was to upgrade Blender from 2.82. 2.83 had big improvements in skinning for the glTF importer.
By the way, if you ever have issues with how a skinned mesh looks in edit mode, you can also try toggling the "Guess Original Bind Pose" option on the glTF import screen.


How to check if EEVEE or cycles is used?

You can enable Material Output for a specific render engine. This will allow you to create a single material with one material output for Eevee and one for Cycles.


How to scale all key frames in a layer of grease pencil?

If you parent your grease pencil to an object - in this example an empty - the children will follow the scale that mum or dad tells them to do...


Move an object while connected tubes "follow" it, automatically stretching and shrinking

While I don't see a way to automatically detect collisions, I expect some things can make your task fairly easy.

The first task of placing an object within a modelled room is easy. You can use snapping to place a mount point onto the wall. then by 'locking' the right axis of each wall mount you can easily move the mounting around the wall and have it stay on the surface, a small adjustment can be made to transfer it to another wall.

Curves are defined by a number of control points. By adding a bevel to the curve they become "tubes" that automatically flow between each point.

By using hooks each control point can be moved while the tubing adjusts to suit. One end of each curve can be hooked to the wall mount, the other end to the object, and then a simple empty can be used to adjust each point in between. Instead of using hooks for each control point you vould edit each curve manually.

In the following example that I created for the previous screenshots, I have two curves, that go from the wall to a fume extractor. Each curve has two control points to adjust how it flows from the wall to the extractor. For easy viewing the building is set to always draw in wireframe.

To use, you place the mounts on the wall, then position the extractor and then adjust the curves to flow nicely between the two.

While I have used a nurbs path in this example, you can also use bezier curves to get more control over where the curve goes to and how sharply it bends at each point.


Cycles procedural material displacement is different (up/down) on different faces

You could use a color ramp and set the black value to a grey to add a plateau:

Node setup:


What seems to be happening is the light is hitting the bottom of the glass, going through it, and then reflecting upwards hitting the top of the bottle, creating a weird reflection. The reflection changes based on the angle you look at the object.

I'm pretty sure that this is working how it's supposed to. It just looks weird to the eye. There are a few things you could check/do to fix it though.

Check to see if the liquid, is touching the glass. This is known to cause artifacts.
You could change the camera position or lighting to make it less
apparent.
You could also adjust light bounces in the light paths drop down in
the render panel. (this would decrease the realism, but you could lower the bounces so that the light doesn't reflect enough times to cause that reflection)

I think you might benefit from this tutorial. I linked it at the point where he started doing the liquid.


Creating a emission plane and hiding it in Blender 2.81

Use the Light Path node to make the material appearance different from its influence.

From Add > Input > Light Path use the Is Camera socket to mix between your Emission Shader and a Transparent Shader.


2.92.0 bug? EEVEE AOVs are not fully opaque

Was able to reproduce, bug report has been filed.  ColorRamp wasn't the issue.


Hiding inner faces of transparent object in render

You can select all the outer faces and assign them a vertex group:

Then give your object a Mask modifier with the group as Vertex Group:


Why can't I use a vertex group to control a particle system's density?

Never mind, I guess I was supposed to assign the vertex group in the particle system, while not in Edit Mode. So make sure you create a vertex group and then apply that vertex group in the density panel in the particle systems under Vertex Groups. And make also sure you aren't in Edit Mode.


When I sharpen edges, why do I get random spikes?

welcome to BSE, you need to work more in the topology, that spike is an "ngon" that got triangulated by the sub-div modifier, for working with surf you need to have a decent quad topology to generate the shape you want.... you small objects seems not merged to that ngon, keep those separated like that...


How to restore visibility of animation panel?

Every portion of the window can be configurated rappresenting an editor, the animation-related windows are: timeline, graph editor, dope-sheet, and NLA editor.

You can create a new portion of window by selecting and dragging the little triangle in the up right angle of every portion of window. Right clic on the separation line between two windows to join them.

Check also the upper header (info window), for default templates of windows organization.

If you have the option "back to previous", click it!


How can I render a toon character's head to always be visible in front of his body?

you could make it a flat object with a constrain to always  point it to the camera


Why does my object lose color when the slot is changed?

It doesn't exactly "lose color". Paint slots are handled as layers, so if you add a new slot to your model it "spraypaints" the model with whatever colors you have in that slot. Since in your case there are no colors (or a texture, to be more precise) the model appears to have no color at all.


So I figured out how to make it myself and folks can find the script here:

Code on pastebin

If you have a very simple scene then you might get some wonky results, as this calculates based on render duration and every single time you render a frame (even the same frame), you'll get different times. The best use for this is on a semi-complex scene so that the various samples (diffuse, transmission, etc.) really get to take effect and modify the total render time.


Using own.hit Object List? with ["Near"] sensor

You can do it this way.

from bge import logic

if logic.getCurrentController.sensors['Near'].positive:
    for obj in controller.sensors['Near'].hitObjectList:
        print(obj)

KX_NearSensor

KX_TouchSensor


How can I create a cylinder linking two points with Python?

i wrote my own script, as there is no way to do it with blender API direcly:

def cylinder_between(x1, y1, z1, x2, y2, z2, r):

  dx = x2 - x1
  dy = y2 - y1
  dz = z2 - z1
  dist = math.sqrt(dx**2 + dy**2 + dz**2)

  bpy.ops.mesh.primitive_cylinder_add(
      radius = r,
      depth = dist,
      location = (dx/2 + x1, dy/2 + y1, dz/2 + z1)
  )

  phi = math.atan2(dy, dx)
  theta = math.acos(dz/dist)

  bpy.context.object.rotation_euler[1] = theta
  bpy.context.object.rotation_euler[2] = phi

enjoy :-)


Can the clone brush sample surfaces facing away from the camera?

If you want to clone from a surface directly behind the brush, then no, this isn't supported.

However, if its slightly offset - you can do something like this using hidden faces.

disable back-face culling in the project paint options panel.
enable face-masking in the header (MKey)
select faces on the clone source, then Hide with HKey.
select faces to paint onto(note that border select works well in both cases).
paint...

Another option would be to duplicate the geometry in editmode and move it so it can be used as a clone-source, though this is isn't very convenient.


Only half of the object is getting texture, the other half is dark

Incorrect, corrected after the first image

The issue is with your material's bump node. Change it to a Normal Map and everything works fine.

I don't know why the Bump node doesn't like hollow shapes, but every replica mesh I created and plugged into the material always ended up with those black surfaces. When I unplugged that Bump node, the problem went away.

Edit:

Seems like I finally found the source at the same time as HelloHiHola. You probably meant to plug in your normal image into the Strength input, not the Normal input.


Why is my animation performing weird rotation from one frame to another?

This answer is late because I completely missed your comment. Sorry about that! This topic is very large and can take a lot to understand all of it, so I will keep my answer as simple as I can to address the question.

There are two terms I will use in this answer and it is important to understand the differences: rotation and orientation. Orientation is the transform of the bone at any given point. A rotation is the action or difference of changing the orientation of a bone.

Euler:

Euler rotation math is a common cause of problems in animation, primarily because the underlying functionality of Euler angles is hidden from the user. This is something you're discovering for yourself. Euler angles are compound calculations. Each axis is calculated in sequence based on a particular order. In XYZ order, X is calculated first, Y second, Z third. Because of this ordering, axis rotations can counter each other. You don't need to know the particulars of gimbal lock, but when you get further into animation it is good to research. Euler rotations are advantageous when a bone needs to rotate on one axis continually or for long stretches of time.

Quaternion:

Quaternion math is a solution to this problem. When using quaternions, rotations are always interpolated as the shortest path between two orientations. This makes it easier for the animator to work in the 3D view without worrying about underlying functionality. There are no axes fighting each other in the math.

Conclusion:

If you are working in the 3D view, don't need the graph editor, and your bone is not rotating continually in one axis, your safest bet is to use quaternion mode for your rotations. If you rely heavily on the graph editor and you understand the idea of compound rotations, use Euler in one form or another.

For further education, I highly recommend Nathan Vegdahl's Humane Rigging training DVD on Youtube. The video in the link is the start of his explanation of rotation modes.


How to assign a specific weight to vertices? (instead of painting it)

Ah, I was fooling around and found an answer.

In the weight painting mode, use the Vertex selection masking for painting  V
Select wanted vertices for example with Circle select tool C
Set the wanted weight from Tool Shelf T
Weights -> Set Weight Shift+K

In addition, there's a useful addon for setting weight values:
http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Paint/Palettes


Assign mirrored existing weights from bone_L to bone_R vertex group

Method 1: Ensuring that you will always get mirrored weights from the very start of your project.

While in Weight Paint Mode, look in the Properties Shelf to the right of your viewport (press n to bring it up) and select the Tools tab. There is a Symmetry section, as well as an Options section. Do not activate anything under the Symmetry section, as it will not do what you want. If any Axis buttons are activated under the Symmetry section, press them to deactivate them. What this does is add whatever weight value you are painting to the other side of the mesh, but only for the current vertex group, not its mirrored partner.  Instead, you want to make sure that X Mirror is checked under the Options section. This will ensure that whatever weighting you add on one side is mirrored to the corresponding vertex group on the other side. Provided that this other vertex group exists, of course.

Method 2: Mirroring existing weights after they've already been created.

Go into the Object Data tab of the Properties Panel with your mesh selected in Object Mode. Press the Plus Sign to the right of the Vertex Group section to create a new vertex group. Even though you only want to mirror a vertex group, you must create a new one first, and assign weights to it from selected vertices. It seems like you should be able to mirror vertex groups without beginning with a creation step, but mirroring without creating a new vertex group first will actually remove the old weights from the old group and replace them with mirrored versions of those same weights,now on the opposite side of the mesh, which is not what you want. Note that creating a new vertex group first doesn't alter this behavior, but it does ensure that the weight reassignment takes place only for the newly created vertex group, while leaving the old one alone. The end result is that you will now have two vertex groups with mirrored weights. It's just that you needed to manually create the new vertex group before mirroring, to avoid losing the original weights in the old group. So understand that the Mirror Vertex Group option creates no new vertex groups, but merely reassigns existing ones.

Give the new vertex group a name, and end it with either a .L or .R suffix, based on which side you will want it on. Switch back to Edit Mode and select the vertices that will be assigned to this group and hit the Assign button. Make sure the blue Weight bar under the Vertex Groups section is set to a value greater than zero, or the assignment will have no effect (it's usually at 1 by default, meaning full influence).

Now go back to Weight Paint mode so that you can see the effect of what happens next. In the Object Data tab once again, make sure your new vertex group is still selected under the Vertex Group section, go to the Vertex Group Specials pulldown (1) and choose Copy Vertex Group (2). The new one will be given the same name as the old, except it will either have a "_copy" or ".001" suffix, which is not what you want. Rename it to have a '.R' or '.L' suffix, whichever is the opposite of the one you first created.

Now that you have two groups, instead of one, you can mirror the new one. As explained earlier, mirroring will remove existing weights from the selected vertex group, but that is okay, because you still have the original vertex group's weights in tact. From the same Vertex Group Specials pulldown, with your new vertex group selected, choose Mirror Vertex Weights (3). You should see in your viewport that weights have appeared on the opposite side of the mesh.


how to change the texture of the material from polished to natural chipped

You could do it procedurally:

Use 2 Noise nodes that you mix into a MixRGB (Overlay mode) node. Then you can add some glossiness or bumpiness, it all depends on the realism you want to give to your material...


Does the NVIDIA Quadro FX 5600 1.5 GB. meet Blender 2.8 minimum system requirements?

I'm not sure about that specific card but it should work even if it is legacy (cycles GPU compute may not work Eevee will still work). I have a  Quadro 2000 and blender works fine on mine (for most work loads). After looking at comparisons between the 2 the Quadro FX 5600 is better than mine therefore it should work with blender.
Graphics support


Select the face and create a new orientation coordinate system clicking the plus button. Then set cursor to selected, then select the head of the bone and set selection to cursor, then do the same with its tail ( so both are in the same spot) then (still with only tail selected) press G Z, move the mouse and confirm LMB.

This procedure will automatically set the roll.


Can you bake keyframes in BGE and have them work in cycles?

In short, yes you can. It is as simple as activating a checkbox called Record Animation in the Menu, and then playing your game:

When you hit Esc to exit the game, it will take a little while, as then all keyframes are evaluated. Once done, you can select the object and edit keyframes in the Graph Editor, although it might not be great fun to do so:

Using clean channels or clean keyframes you can simplify the curve, but the risk is to change the animation too much:


You have some seriously uneven and messed up topology in your mesh, there are vertex overlapping faces, tris mixed with quads and ngons at unexpected places, all that contributes to bad topology and potential artifacts at render time.

Anyway there's an (apparently) useless and undesirable Bevel modifier and the end of your modifier stack causing trouble in the resulting mesh.

It is causing artifacts even in the viewport, and some more in the rendered view. Disabling it seems to mostly fix that problem.

You may want to read up on why quad based topology is important

EDIT

You may also want to remove doubles in your mesh (under edit mode select all and W > Remove Doubles) and recalculate normals (under edit mode select all and Ctrl + N)


How to check if a known object is intersecting with an object using python

Use some kind of quick bounding box culling like this (javascript demo on collision detection by mozilla, but should be easy enough to adapt for your case) to eliminate objects that cannot overlap. Beware that Blender objects' provided bounding box is in object space, so may not be axis aligned in world space. You will need to convert it to world space and then generate a new bounding box of that bounding box that is axis aligned.
Then build bvh trees for each mesh that may intersect, and test, re-using the tree for your test object.


Weight painting on low poly model acts weird

You have duplicate vertices in your model, and you are working in opaque mode ('limit selection to visible'), so only one of the duplicates can be selected. Several ways to get around this, one would be to select the vertives you want to work on in edit mode, then switch to weight paint and activate the icon directly to the left of the layer selection block (a cube with one highlighted vertex, "vertex selection masking"). Then you'll be able to only work on the selected vertices (you might need to unselect 'limit selection to visible').

Or you could remove the doubles in edit mode...


Can Blender be used for business purposes?

Blender is GPL licensed - and subject to all the terms of GPL licensing (barring some components of it).  For more information, look here: https://www.blender.org/about/license/


Cycles, shade based on proximity to another object's geometry

Dynamic Paint is the perfect tool for what you're trying to achieve.Here you find all information on the topic you nead.In case from some reason this tutorial will disappear,I'm talking about this:


Render's shadow always looks pixelated with Blender Render

You are probably using Shadow Maps type of shadow in your lamp object.

Shadow maps are good for real time rendering, but not really necessary for "offline rendering". Switch to other "true" raytraced shadow type.

You are also possibly in Game Engine mode, switch the active render engine at the top of the screen


This is an addition to @Denis 's answer.

There are other armature deform options, but with automatic weights looks like it's the most reliable with empty groups weights in a close second. It all just depends on how you want your mesh to deform. I made a turkey to show you:

here is the article to look to for a run-down on armatures, by yours truly.


How do I batch import one format, then export to another?

Here is an outline:

Make sure 3DS importer and Three.js exporter are installed and enabled

# test
hasattr(bpy.types, "EXPORT_OT_threejs")

# enable
try:
    bpy.ops.wm.addon_enable(module="threejs")
except ImportError:
    print("Threejs importer addon not available")

Loop over all the files and perform below actions for every single one,
you may use glob.glob() or os.walk() unless you want to select the files via UI
(see the Operator Import tempate, you will need to provide
files = bpy.props.CollectionProperty(type=bpy.types.PropertyGroup), docs)
Clear scene if desired, e.g.

 bpy.ops.object.mode_set(mode='OBJECT')
 bpy.ops.object.select_all(action='SELECT')
 bpy.ops.object.delete()

Import 3DS, basically call the operator bpy.ops.import_scene.autodesk_3ds(filepath="the_path_to_file.3ds")
The importer should select the imported files, but there will usually not be an active object. To run operations on the imported data or for some exporters you might need to set one object active (or process each individually and make one active after another).
Export to JS, basically call the operator bpy.ops.export.threejs(filepath="target_file.js", **kwargs),
kwargs stands for all additional arguments you may wanna give to the export operator.


Audio and video segments are not the same length

Modern codecs like AVCHD  often are not well supported by Blender's decoder. You may find that these clips are frame segmented, which Blender incorrectly treats as sort of interlaced, thereby reducing the frame number but maintaining frame rate. Only solution is to transcode into a format that Blender does understand. Check out this thread for details on the effect of frame segmented media in Blender. Sorry.


By pressing D over an input field you are telling Blender to create a driver for that value. A driver is a way of controlling one value (the driven value) by another value (the driver). For example you  could drive the scale of one object by the rotational value of another.

To remove the driver you can either right-click on the value and choose 'Delete Drivers' or you could:

Navigate to the 'Graph Editor' from any screen area:

Change the view from 'F-Curve' to 'Drivers':

Shift select all the driven channels in the list and press X to delete them:

If you want to view and delete drivers for multiple objects at the same time make sure to toggle off the cursor icon which limits the view to currently selected objects:


2.8 how to move 3d curser like a normal object?

You could use the cursor tool on your toolbar, drag it and then press x,y or z to move it along an axis.


How to disable AO on smooth edges, but keep it enabled on sharp edges?

Adding an EdgeSplit modifier before a Subdivision Surface instead of doing autosmooth seems to alleviate the problem. Dirty, I know...


How to merge two objects at identical face?

I am not aware of a specific function that would align and merge at the same time so doing it manually is the best option that I know of.

First, to align the two objects select them both and in the properties panel (N) you will see rotation values, right click on them and click "Copy All To Selected" you should get something like this:

Then, under the viewport you should see a magnet button, enable the magnet and then set the snapping to vertex:

Select your "Plane" object and then press G after moving it in the general direction of the other object (its best to view it from the angle of the other face) the object will align to the vertex on the other shape:

After that switch into edit mode and keep the whole "Plane" object selected, then align one corner to the other and it will be perfectly aligned:

Finally, exit edit mode, select both objects and hit Ctrl+J, now go back into edit mode and you can edit both objects, simply merge the vertices together (This will be difficult but not impossible just click around the vertices and it will select both sides) and delete the inner face to clean up and you're done! :) Final result:

I would just like to say that although this method works it is completely unnecessary as these objects should've been created together in the first place, from what I saw there was no need for these to be separate objects, in future create objects in edit mode or extrude instead of creating new separate objects it will save you from going to all this effort and will be much faster too. Happy Blending :)


Yes, Orientation is everything in 3d and your question has many possible answers due to what your object has had done to it. Like, Cloning, Parenting, Applying scale, transformation, and rotation can affect how an object behaves. this video may help
https://www.youtube.com/watch?v=ABayYXu7OfI


How Can I make a Copy of an object multiple Times Knowing that it must be animated as the original?

The easiest solution here would be with DupliVerts:

Take your animated objects and bundle them as a group (Ctrl+G). This is mostly for your convenience later.
Name that group something relevant (Groups panel in Object Properties). Also a convenience.
Back in the 3D View, create a Grid object (Shift+A→Mesh→Grid).
In Edit mode (Tab), scale up the grid so it's larger than your molecule. It's important to do this in Edit mode so your scaling doesn't get messed up.
Select one of the objects in your molecule group and then select all of the other objects in the group (handy shortcut: Shift+G→Group... this selects all of the objects that are in the same group as your active object).
Shift+Select your grid object to make it your active object.
Make the grid object the parent of your molecule objects (Ctrl+P→Object).
In the Duplication panel of Object Properties, click the Verts button.
Boom. You should see a copy of your molecule at every vertex of your grid object. And when you playback your animation (Alt+A), you should see all of your molecules animating at the same time... much like the icospheres and Suzanne heads in this blend file and the screenshot below.


How to make the grid infinite in User Ortho Views?

I don't believe there's an option to do this specifically for orthographic mode, however if you go to the property panel (press N to make visible), under "display" you can set the number of lines to show on the grid. By setting it to its max value of 1024, this will achieve a similar effect to what you are looking for.


How do you rig eyeballs without affecting the rest of the face?

Here's my workflow for eyes:
First clean any weight paint of your eye bone from your face mesh.
If I understood it correctly face mesh is connected to the eyes? If that's the case then select face in object mode > Edit mode > select eye faces > ctrl + I > H, this will hide everything except eye(s).

Select bone of an eye in pose mode > Ctrl + tab.
Now we have to apply our selection from edit mode.

Click on the second from the right side icon.

Weight paint whole eye with value 1(red). This creates vertex group with weights for my eye bone.

Hope this helps.


Execute Node Tree returns different result each time it is run in static setup

By reading the transformation values of your instances in the Object Transforms Input node and later setting them on the same instance in the Object Transforms Output node you create a feedback loop. Each time you execute the node tree you modify the object based on the values of the previous iteration and not on some default state. Only when you increase the number of instances you get “fresh” objects, which is why the instances might appear at the desired location at that time.

My suggestion is to not use the instances' Object Transforms Input but rather compute the transformation values some other way. For example by using the Index of the loop. You could also add some other objects' Object Transforms Input, e.g. the location of another cube to influence the offset of your instances. You only have to be careful if you write the transformation values that you're reading.

Edit:
I modified the previous solution to use a transformation matrix instead of a mathematical expression. A combination of a list of matrices or repeated multiplication – as AN's Matrix Math node has no Power built in – allows the recreation of something similar to Structure Synth's iteration function. A more complex node setup would also allow it to pick a different matrix (or a mixture of them) for each iteration at random, resembling the assignment of multiple definitions to the same rule in Structure Synth.
If you want to avoid the matrices you could also try to read the transformation values of an object's predecessor in the object instances list.


ImportError: dynamic module does not define init function (initbpy)

I also ran into this problem. I think Python3.x is needed or see bullet points below for more information.

Failed: python -c "import bpy; print('hello');"

Worked: python3 -c "import bpy; print('hello');"

"get Python3.x-framework from Python.org and install it."
"The Python version requirements are the same with building a regular blender binary (if Blender us using Python3.5 then there is NO WAY to use another version - 2.7/3.2/3.4 will all fail)."

Source: https://wiki.blender.org/index.php/User%3aIdeasman42/BlenderAsPyModule


How do you get hair to take on the color of the mesh it's attached to?

You have a Noise Texture node plugged into the Displacement socket of the Material Output, it messes up the render.
I don't know what you were trying to do with it but anyway you can't directly plug a Noise Texture into the Output, you need at least to put a Vector > Displacement node between the 2.


What settings will preserve quality when I output an edited .mp4 for Youtube upload?

Work from the best quality sources you can, and keep the work in EXR stills format until you are ready to conform the work to a master.
BINAC: Blender Is Not An Encoder. The bulk of your issue here is largely because you are relying on the various encoding settings from within Blender. Blender is not and should not be considered an encoder. Work from step 1 and provide a series of still images that your conformer can work with. For example, outputting to 100% quality JPEGs from your EXRs and then encode them with FFMPEG. FFMPEG offers many preset configurations that will deliver results that are leaps and bounds better than Blender's encoding defaults, as well as provide you with the flexibility to encode shot by shot if required to a suitable format.

For more information as to the low level internals and the whys regarding the above, you can see an answer I have posted here. Good luck.


Looks like you'd need to experiment.
Pick a small task, give yourself a week to solve it, reflect, iterate (cf. PDIA, Cynefin-complex, Fail faster).

Here's some ideas for you to test:

Making a different software out of Blender might require changing the source code, so try to build Blender from source. See if the build cycle is fast enough.
You'll likely need to remove the unnecesary tools from the user interface, so see if you can.
You'll likely need to add new tools or behaviours to the user interface, so see if you can.


Try using a property group class where you can store all your properties.

import bpy

class MaterialSettings(bpy.types.PropertyGroup):
    my_int = bpy.props.IntProperty()
    my_float = bpy.props.FloatProperty()
    my_string = bpy.props.StringProperty()

bpy.utils.register_class(MaterialSettings)

Assigning these values to the Object like this:

bpy.types.Object.my_settings = bpy.props.PointerProperty(type=MaterialSettings)

Note:
you can choose a custom name instead of 'my_settings'

And the name after the 'type=' is the classname of your property group .

You can access these properties like this: object.my_settings.my_float = 3.0
object.my_settings.my_string = "Foo"

This way, only the propertyclass will be visible in the properties tab and is only editable via script!


Yes. The Blender cloth simulator will not work if you only have a simple un-subdivided mesh. If you go to edit-mode, and set the subdivision setting to around 50 subdivisions, then the simulation should work well. Setting the step quality of the cloth simulator to about 7 yields a fast simulation, while not using up too much RAM.


What's the best way to model complicated pipes?

first create a circle of 16 vertices or 32 verts (16 its better for less polycount), then convert it to a curve with Alt+C , then add a bezier curve and set the bevel object to that circle, also if there are too much edge loops reduce the resolution size to 6 or 8, then stretch or shape your curve recording what you want in edit mode.


Cycles, weird shadows appear on baked textures

Dark areas on textures normally have one of the causes listed below:

You have overlapping geometry
You are baking combined textures, which means that you among others also bake the shadows.

According to the screenshots you provided we have both cases here.


Blender's official Archipack addon require additional setup steps in order to work.
Preferences -> Add-ons -> archipack -> Setup Actions -> Render Thumbs

From:
https://github.com/s-leger/archipack/issues/88


Python 2.8 - plane bevel disappears on object join

As well as an object being selected, one object is known as the active object, this object has its properties shown in the properties panels and may be affected by some operators that will ignore the other selected objects.

In your case, when joining multiple objects, the modifiers of the active object are kept while modifiers on other objects are disposed of.

You could set the plane as the active object before the join or add the modifiers after the join. Most likely you want to apply the modifiers to the plane so that the bevel on the plane is kept and is not also added to other parts of the joined mesh.


Emission plane is casting a shadows in cycles

They are not casting shadows, they only emit light from the faces, not form the edges. You can try to extrude the faces, but even so, the faces on the edges won't emit enough light to match the one coming from the front and back faces.


How to start an animation at a different frame than that of the start of the loop

Try this:

It starts one animation and plays it once from frame 1 to 20. Once that animation reached frame 20 the actuator isn't active anymore. This means that if you set up an actuator sensor to a Nand controller to a action loop frame 5 to 20 it will work.


Object location before and after parenting

Use AltP > Clear and Keep Transformation.

This will unparent the child and apply the transformation of parent.


Animate with position and orientation from txt file

It's very possible, and doesn't even sound difficult to do.

Make sure Object.rotation_mode is 'QUATERNION' (once for the object):

ob = bpy.context.object # active object, assuming there is one
ob.rotation_mode = 'QUATERNION'

Reading the file:

import bpy
from mathutils import Vector, Quaternion

file = open("input.txt", "r")
for line in file:
    x, y, z, q0, q1, q2, q3 = line.strip(" \t\r\n[]").split(",")
    loc = float(x), float(y), float(z)
    quat = float(q0), float(q1), float(q2), float(q3)

    # Or cast to Vector / Quaternion type if you need any methods of them later
    #loc = Vector(loc)
    #quat = Quaternion(quat)

I assume line 1 in the file is meant to be the first frame in Blender and so on. Let's keep track of the line number:

for i, line in enumerate(file, 1):
    ...

Assign the location and the rotation in our for-loop:

    ob.location = loc
    ob.rotation_quaternion = quat

and insert keyframes for frame i:

    ob.keyframe_insert('location', frame=i)
    ob.keyframe_insert('rotation_quaternion', frame=i)

Finally, we close the file:

file.close()

For a better performaning way to animate with python, see:

http://www.blender.org/documentation/blender_python_api_2_69_10/info_quickstart.html#animation


Sort of..

You can insert a "Value" node (under Input) into your Cycles shader, then add a driver to it (right-click the parameter and select Add Driver); get the driver to copy the rotation axis of whatever object you want to use:

With the Value node selected, go to the Graph Editor.
Switch mode from F-Curves to Drivers.
On the left hand side of the editor, find the "Value" inside Material > Shader Nodetree and click on it.

At this point you might need to reveal the panel at the right hand side of the editor - hit N if you can't see it.

In the "Drivers" panel, change "Type" to "Averaged value".
In the variable panel, make sure "Transform channel" is selected, then specify your Object from the input by name, change Type to "X Rotation" (or Y rotation, etc) and you should see its current value appear.

You can then attach the output of your Value node in Cycles to a Hue/Saturation node, or to the Fac of a Mix node to alter the colour. If you want each rotation axis to be available in the material, add a separate value for each rotation axis.

If you want to do something like map each axis directly to a part of the colour - e.g. X becomes R, Y becomes G, Z becomes B - add an RGB input node instead, right click the colour and add a driver to that. You can then find it under "Drivers" the way you might have found the value, and you can drive the four different components of the colour (R G B and A) individually.

Worth noting: the rotation value will hit the driver as radians, not degrees. It's also possible that the driver will get an input which is less than zero - you can get around this to an extent by setting the Type to Scripted Expression and using an expression like "abs(var) % pi" to keep the colour away from black.

There's an annoying drawback to this method though: as far as I know, you'll need to set the driver and material up separately for each object - so you'll end up having as many copies of the material as you have colour-changing ellipses. If your Cycles node setup is particularly complicated and you still want to be able to tweak it, you might try Grouping all the nodes in your material except for the Value, but use the Value as an input to your group. If the Object Node had X/Y/Z Location/Rotation/Scale, this wouldn't be necessary.


How Can I make a Fluid Simulation liquid become gooey or viscous?

Primarily you want to adjust the viscosity settings. The smaller the viscosity the more watery the simulation. Note that the exponent value is negated so increasing the exponent makes the final value smaller.

You will also find that the real world size makes a difference. A real world size of 10.0 will give a watery result while a real world size of 0.2 will be closer to a slushy with the same viscosity.

As for twisting the result, it will depend on the effect you want. You could use a simple deform modifier or a lattice deform. With a thick fluid sim you may also be able to use a collision object that spins around.


From my comment

  Bones/Joints are much better suited for movement which rotates around a pivot point, namely the eyelids and the jaw.
  The Jaw will interpolate strangely between open and closed if it is just shifting between a shapekey. A bone would ensure a rotation similiar to the real world jaw bone.
  Shapekeys are best suited for the eyebrows, mouthcorners and and other movements which rely more on muscle contractions instead of mechanical relations.

Edit: To understand the images illustrating this post, you must note, that I have used a custom weight paint range. Every vertex weight above 0.000001 looks similiar to the standard weight settings. However, a weight of 0.0 is set to white. I did this to be able to tell the difference between a very small weight (e.g. 0.00001) and actually no weights, which is not possible with the standard mapping of blue.

Weight Painting the Jaw

Make sure all of your head geometry is associated with the head bone.
Add the jaw bone, make sure that

there is a vertex group named exactly like the jaw bone
the jaw bone has deform enabled
the jaw bone is part of the armature used by the the mesh (via the armature modifier)
your geometry is not unnecessarily dense (it seemed you have applied the subsurf modifier, this makes the process very difficult. I would unsubsurf the model 1 step with the decimate modifier.)
in weight paint mode, Auto-Normalize is checked

Lock all groups except for the head and jaw vertex group.
Roughly paint the jaw to the jaw bone.

Now open the jaw with the bone and make sure the complete jaw is fully assigned to the jaw bone.

Now choose the the mix brush and paint weights of approximately 0.5 on the corners of the mouth. Choose other quantized weight for other areas if needed. Roughly block out the correct shape. You can raise the mouth corners by adding weights to the head vertex group and you can lower them, by adding weights to the jaw group.

Using the blur brush smooth the area. Then use the add brush with a very fine Strength to shift single vertices untill the desired shape is reached.

Image shows the head's weight group.


As you already noticed, the 3d Cursor is your friend.

Either click LMB  anywhere in the viewport or set its xyz location values directly (Transform Panel N > 3D Cursor). Object Mode or Edit Mode doesn't matter so you've got the control you need. When done, open up the Toolshelf T, go to Tools > Set Orgin and select 'Origin to 3D Cursor' (in Object Mode) or use  ShiftCtrlAltC shortcut for that.

Also see: Precisely move the 3D cursor?


Cycles render showing up black and weird

The problem is that your entire building has a material on it "realistic glass"

Take this off and viola problem solved. If you would like to put glass on one part of the mesh see this question.


Can the sequence of objects created by the Array modifier be scaled down linearly?

The solution for this is the "Object Offset" of the Array Modifier.

Select the object with the Array Modifier and press Shift+S selecting to place the "Cursor to Selected"
Add an "Empty", which should result it being placed at the cursor aka same location as the object.
Go in the Array Modifier options and activate "Object Offset", followed by picking/selecting the "Empty" as target right below.

Now you can select the "Empty" and by scaling it each clone will recieve the scaling like this:

Be aware though that everything you do to the "Empty" now affects all the clones, moving, rotating, scaling as well as the combination of those can fast result in sometimes wanted, other times unexpected results.

Happy Blending


Ok. You have Fluid modifiers everywhere! On the Scalp, on the Body and, on the (hidden) Hat object. (How did that happen?)
Here is a fix list ;-)

Remove the Fluid modifiers from the objects
When you remove the Fluid modifier from the Scalp object then the main hair will be modified (2nd picture of the model in the question). There is a long "children" strand on the left side of the head, far away from the hair particle (hair guide). The reason for this is that [X] Long Hair is ticked in the Hair Particle Settings for the Interpolated Children. Turn off Long Hair for the children. Then the children will follow closely the hair guides and the hairstyle will look like before.
If you make the main hair static by turning off Hair Dynamics the hair will change and look like in picture 3. This is because there is a Collection named "SCALP" set in the Hair System Settings → Field Settings → Effector Collection. Clear the value here and the hair will look fine again.

Side notes:

I've tried to run your hair simulation but when I press the Play button the frame jumps 1, 30, 70, 123, ..? I have no idea what's going on there. If I move the fixed Scalp object into a new blend file the hair animation works fine and the tips of the 'Fizz' hair move slightly.
The 'Body' has a Subdivision modifier, level 3 for viewport and render. This results in 280k faces and 500k tris. Maybe turn it down to 1 and 2? There is no difference between level 2 and 3 except for the 200k extra faces (70k -> 280k).


Ctrl Alt Numpad 0 keeps moving my object?

The answer was to first select the camera and press Ctrl+Numpad 0 and then perform the Ctrl+Alt+Numpad 0

User CD38 on http://blenderartists.org/forum/archive/index.php/t-78116.html explains:

  I'm pretty sure you made the body into the camera at some point with
  an accidental Ctrl-zero when it was selected. You need to be careful
  with those Numpad-zero commands. Here they are:

  zero alone: changes the viewport so you're looking
  through the active camera. ("I wonder what the camera's seeing?")
  Ctrl-alt-zero: moves the camera to match the current 3D
  viewport. ("I like this angle; let's put the camera here.")
  This is why your humanoid is jumping around and looking
  inside itself. Very mind-bending.
  Ctrl-zero : makes the selected object into the active
  camera. Anything can be a "camera." In this case it's your
  humanoid object. This is poorly documented and seems to cause
  all kinds of grief because it's an easy misstep.

  Select the real camera with the RMB and do Ctrl-zero and all should be
  well.

(I found this answer and decided to document it here on stackexchange because I had a hard time finding the answer and would have expected this question and answer on this site)


Materials, textures and how they relate to models before/after render

You got most everything right but there are a few misconceptions there.
Model
A model is the geometry giving shape to a 3D object, it is often of Mesh type but may be also composed of other geometry types, like Curves, Text Objects, or less commonly in Blender NURBS. It may also comprehend other animation related data like rigging, shape keys, and armatures.
The formats you speak of have nothing to do with models themselves, though they serve as way to export them. They are mostly interface file formats useful for transferring data between different applications, Blender does import and export most of them, but to faithfully save your data you must exclusively save in the native .blend file.
Texture
Textures are for the most part regular 2D images as in jpeg, png, tiff, tga, EXR image files. They are just a name for an image that will be controlling a property of a material, it is not a file format that contains "1+" images, it is an image. They simply describe color information, they hold no information regarding surface properties of an object themselves, and can't be used alone for the most part, but can however through a material serve various purposes like provide actual diffuse (visible) color of a material, or other surface properties like roughness (bump or displacement maps), shininess (glossiness or reflectivity), emission, and many other properties.
There are two main types of textures, actual image textures, as described above, using an image file, or procedural ones, generated by the rendering engine (generally can't be exported or used elsewhere outside the source program).
Material
A material is the collection of image textures, procedural textures, shaders, and surface/volume properties that describes the final appearance of the surface. It may include reflectivity, lighting, color and/or volume information. Materials can under certain circumstances be baked into a "static representation" of the surface for export, but are otherwise for the most part not exportable
A material can use any number of textures or none at all, and an object can have any number of materials (except for certain game engines). Materials are assigend to objects using Material Slots but only one can be assigned per face at each time. Of course using too many textures and/or materials may have a negative impact over performance of a scene or rendering.
Rendering
Rendering Is generally used to refer to the process of transforming a Scene (composed of 3D models with Materials) into a 2D image (like taking a picture with a camera). The process of transforming materials into textures, although also achieved through the same rendering process, is generally referred to specifically as Baking. Just to be clear, baking obligatorily involves rendering, but rendering doesn't necessarily require baking.


Animation with Physics (Cloth | Collision)

Cloth -  You've already found the settings that prevent the cloth falling through the wider section of the cylinder.  Your second query, re: stretching at the cloth's aperture...

Edit 17th July 2019 -

No stretch -  An alternative solution - (See below for the other)

Scripting might be able to circumvent Blender's physics from stretching the cloth's aperture but to do it from the desktop, it appears only a slight-of-hand workaround will avoid this.

The physics engine starts expanding the hole when it approaches the upper end of the pipe, so why not decrease the diameter of that pipe.  The hole will still expand but to a lesser degree.

Next we duplicate the pipe and strip that of all physics and animation so it's only scenery and therefore incapable of influencing the cloth.  That's then expanded in the X & Y axis' so it's the same height but fatter.

The original pipe (with physics) is made invisible but will still be seen by the physics engine and affect the cloth as before.

The end result is that the cloth will appear to be a snug fit at all times.

-===============-

Info - The cloth's wriggling is stopped by virtue of a swap with a duplicate of itself that's frozen at the switch-over frame, (the physics modifier applied).   Not recommended for beginners.  Post production in the VSE would be an easier way to achieve this.

-====================-

The earlier solution/suggestion -

It appears that inserting a hole in the cloth gives rise to unavoidable stretching at the aperture as it approaches the upper end of the cylinder.

A convincing workaround would be to add a mesh (non-cloth) ring or collar with the same material as the cloth.  That's then animated so it follows the cloth's descent.

Rather than add a new ring, the original cloth was duplicated and cleared of physics and animation at frame 1.

The outer faces are cut away, leaving the original material in what's left.  This should make it easier to match up should the cloth be textured.


Move connected elements along their individuals Nomals

AltS, the shink and fatten tool, will move vertices along their individual normals.


You need to run the Blender executable from the command line.

In Windows this requires you to run a new Command Prompt and the execute blender.exe from the correct location.
In Linux/MAC the process is similar.

On my Windows machine, I go to the Start Bar and type in Command

in the new window I type the directory to where Blender was installed followed by the program I want to run, blender.exe

To capture all the output a redirection character > is used.

Finally I have a folder on my C: drive called "tmp" that I know I have access to write to. You will have to enter a folder and filename your Windows user can write to.

After running Blender the new file myfile.log has the following contents. This was after simply opening and closing blender. (type is a windows program that just dumps text files to the console)


How to get my [solid mode] object OUTLINES back?

There are a couple places you can enable outlines. The first is within the viewport, to highlight selected and active objects. You can find that option here:

The other is in the object properties, here:

Enable wire to see the black edge outlines regardless of selection. Enable "Draw All Edges" to display all edges, whether coplanar or not. By default, coplanar edges are not drawn.


hit the 1 key to go to Vertex select mode. Deselect everything, tap B for Box select and drag box around bottom vertices to select those.

Then hit X and select vertices to delete.


Absolutely no light showing...totally at a loss

It seems fine for me, I get quite a neat render.
But if you want it to light up all of the boxes, just change it to a sun lamp.

If this is not what you were asking for, or I am not clear, please tell me.
Thanks!


How to get actual rendering progress and estimation from render_stats python handler?

I know it's not the best, but the best I've been able to come up with is code that processes the console output:

Output gives you the render time of the last frame
Output tells you the frame number that was just rendered
You know how many frames are in the complete render, which you can pass to your program
You know the start time of the render

From the above, you can calculate the average render time per frame, which I've found after just a few minutes becomes a pretty stable value.  If the number of rendered objects per frame changes dramatically over time, then of course the average value will change, but given the average render time per frame, you can come up with:

Number of frames which were rendered - grab that from the console
Amount of time elapsed (Current time - Start time)
Current running average render time per frame
Frames left * average time/frame == Render time left

If you have multiple scenes within an animation, you can then also do per-scene calculations, along with the overall animation calculation.

Again, it's not the optimal solution, but it's pretty easy to put together, and it does an effective job of informing you how much time do you have to go before your animation is done.

I hope this helps.


Select the outermost contour of an imported SVG

I went for the solution to iterate over the imported object. For reference the import routine, to see how the SVG gets imported in detail. The data is avail in the objects data.spline collection then.

The correct function relies on that the remaining element has to be the first object in the collection (key not in 0). At least for exported SVGs from corel draw this is true, I guess for others, too.

code snippet I use for now:

# remove all inner elements
svg_splines_collection=obj.data.splines
splineset_to_remove = [value for key, value in svg_splines_collection.items() if key not in (0,)]
for spline in splineset_to_remove:
    svg_splines_collection.remove(spline)

if someone comes up with a better solution I'd appreciate.


Put the mouse cursor over the Collections field and press Alt+H to unhide everything.


bpy.ops.mesh.primitive_cube_add()
a = bpy.context.object
bpy.ops.object.empty_add(type="SPHERE")
b = bpy.context.object
const = b.constraints.new(type='CHILD_OF')
const.target = a


In object mode, put the 3D cursor where you want the origin to be, then select the armature and choose "set origin - origin to 3D cursor".

If you need precision for the placing, select the place (maybe a vertex, a face, a bone or whatever) and press Shift S "Cursor to selected", then again set origin.

When inspecting your file, turn off this option (that I don't even knew it existed).


how to modifing existing torus's minor radius

No you can't. Once a primitive is set you cannot change it's properties, and there is no tool that will allow you to just change the inner radius without modifying the outter. Alt + S will just shrink or fatten the whole mesh. You can however create a new torus and copy location and rotation with the copy object addon to replace the old one. But if you want to be able to go change torus size at all time it might be good to try using a circle curve with some bevel to it instead of a mesh.


What you described in your question is called proportional editing.  to enable/disable this, in edit mode, there is an icon that looks like this:

it is located towards the upper right corner.  When you click it, you can scroll your mouse up or down to make the area you want to edit bigger or smaller.  When you enable proportional editing and move a vertex, the circle you described in your question should appear.  If it doesn't, try scrolling your mouse wheel down until you can see it.  Hope this was helpful!


How to bake normals from sphere to plane

It´s a UV problem. Check your plane's uVs. Should be completed. Else, enter into UV mode and edit the UVs until it covers the coordinates. Also: Good thinking, you've given me a few ideas with this. BTW: How did you get correct UV-localspace object normal ? just baked Normals?


No, this feature is not in Blender.

It has been suggested here:
https://blender.community/c/rightclickselect/7cfbbc/
But so far it has only one vote...

However, Shotcut has this feature:
https://www.youtube.com/watch?v=SkLgpx2E6CI


The falling grid is quite easy to do with particles :

I forgot some things in the original answer, added them in emphasis

add a Grid object with 9x9 subdivisions (= 8x8 faces) (Not strictly necessary, a simple Plane works as well)
add a ParticleSystem on it with Grid distribution, render Unborn, Died, no Emitter. Choose a Grid Resolution of 8.
create a object for your tile, and add it as a Dupli Object for your Psys. Adjust his Size.
create a Plane somewhere under your emitter, and in Physics enable Collision ; check Kill Particles.

The falling effect is working but all the tiles have the same color. To avoid that, you can give them a material like this one :

The Checker texture use the texture coordinates of the Grid object ; otherwise, the checker will apply on each individual Tile object.

The mapping node "kills" the Z component of the coordinates ; otherwise, the tiles will change color while falling (as their Z coordinate changes). Change X and Y Scale to 0.8 match the pattern of the tiles


Is there a way to turn off startup welcome screen?

It's right here in the Preferences (press Save user settings before restarting to test):


Simulation of objects falling one after another

So if you want to test physics, here what you could try:

Create 3 objects, a cube, a funnel, a plane.

Make your funnel and plane Rigid Bodies, Type > Passive (they are obstacles), Shape > Mesh (the topology will be taken into account).

Make the cube a Rigid Body, Type > Active (it will fall), Shape > Mesh (not necessary in that case I guess). Duplicate the cube. If all your cubes are ready and different, just give the Rigid Body to one of them, select all, then the one with Rigid Body and in 2.8, Object > Rigid Body > Copy From Active (in 2.7, T panel > Physics > Copy From Active).

Start the animation, the cubes fall.

If you want to keep them close to each others, create a Force Field > Force with a negative Strength.


How to add a flat base:

First of all, you need to reposition your mesh so that it is horizontal. After that, select your mesh, press Shift + D, click (don't move the mouse), and drag the new mesh down along the Z-axis. Now go into Edit mode, with Tab, select everything with A, press S to scale, Z (limit scaling to Z-axis) and 0. Your mesh should be flat. Go into Object mode, select both your objects, press Ctrl + J to join objects, go into Edit mode again, select the outer edges of both surfaces with Alt + RMB, press Ctrl + E, select Bridge edge loops, and you're basically done.
The result should look a bit like this:


Cut a hole in a cylindrical subsurf without losing overall shape?


How do I emit light from inside a object?

Cycles is a physically based render, and often the best approach is physical recreation.

Components:

Light source
Light cover

Light Source:

This would simply be an emission shader since it is literally a lightblub or LED. I took the button model, and scaled it down slightly on the X and Y axis. I then drastically scaled it on the z axis, and moved it down so the top of the source would to be flush with the of the panel that the button was set into.

Cover:

The cover allows light to pass through it, and is therefore Translucent so a simple translucent node will do the trick. It is also colored, which can be emulated by giving the translucent node a color:

The shape is also important: I added a small bevel to the edges to help see the look.

Final Image

Note

After some experimentation and some research, I discovered that using Sub Surface Scattering (SSS), and placing the light under the button instead of inside, would produce more accurate and better looking results. And it sure did... it also produced exponentially longer render times... even on GPU (using test build)!

Image with SSS:

The major difference is that the light source is under, not inside the button, and is scaled down on the X and Y axis. This method fixed the artifacts that were occurring on the corners, and is more technically accurate. I'd still use the first one, it is way way faster.


Is it possible to generate an image based on edges and corners?

As Ideasman42 hinted, it is possible to invert the normals and bake AO to get what you want. However, this doesn't work at all times.

It works like this. Normally when baking AO you want holes and dents in your mesh to be darker. Not the same amount of light reaches those areas. This can also be used for dirt. If we instead want to mark the protruding edges we can invert the normals. A protruding edge is converted into a dent (sort of). It will render darker when baking AO.

One tweak must be done. If you bake a cube 2 units wide it will be baked totally black. Rays for the inside of the cube (because the normals are inverted) will hit the opposite side of the cube. The Ray length must be set very short. Here are the settings for this:

A downside of this method is that it works porly with self intersecting geometry. Rays from the inside will hit the self intersecting pieces and render dark where you don't want them.

Vertex colours strike me as the superior method in most cases.

Comparison

Made a simple test to compare them both:

For the vertex paint method I hade to subdivide some to get the desired effect.

With baking AO I hade to save the image and edit it externaly (inversion and contrast).


How to make a charachter and/or car move on button press

change your editor type to logic editor,and here is your logic bricks


How can multiple Curves be used to control Camera movement?

You can animate the 'influence' value on each of the constraints you want to turn off. You can either animate the values off over a series of frames to fade the constraint's effects gradually or immediately.

The one thing to note is that when the object is no longer under the influence of the constraints it will return to the position it was at before it was constrained and will not stay at it's current position.

To counter this you can either reposition the object after the constraints are off or animate the 'influence' of some new constraints on at the same time as the old constraints are turning off.


Preview a voronoi/magic/clouds/other texture?

You can't currently preview cycles textures independently in the texture tab, as far as I know, they belong to a completely different rendering system.

You can however get some kind of preview of the texture by previewing the material itself in the Materials tab of the Properties Window by expanding the preview panel and switching to a Flat preview object.