This could be a solution with VSE, but you'll get a blurried image (if you scale 300%)

Some consideration first:

The effect strip will scale always from the center of the image.

If you want to scale from the point A (508x291px from the top-left corner), you have to move the point A to the center first, then scale.

Pan and zoom in VSE

Add the first effect stript to translate the image by the offset you need.
Add the second effet strip to scale (3 = 300%)

Some math:

If your image dimensions are 1920x1080px:

first effect strip (position)

center: xc=960, yc=540

pointA: xa=508, ya=291

translation: xc-xa, yc-ya = 960-508, 540-291 = 452, 249

second effect strip (scale)

scale 3 = 300%

As you can see, the quality of the image is very low.
Since you are scaling 3 times the size, the resolution is 3 times lower.

Note

When you deal with scale in VSE, you have to pay attention to the original size and the render size.

When you add an image (or a movie clip) in the video sequencer editor, the image will be scaled to the render size.

If you want the image to maintain the original size, you have to check the "Image offset" option (transform in pixel).

Doing so, you can pan the image and center the point of interest but you cannot scale it down, because the image will be cropped.

If you want to zoom an image, I suggest you to use the node compositor or a camera moving in front of an image plane in 3d View.

Pan and zoom in 3D View

Using the 3d View, the image texture can be bigger than the render size.

Activate the "import images as planes" add-on, if it is not yet activated

Import the image to stage

Some considerations about the options:

Check "Shadeless"
If you're importing image with alpha channel (png), check "Use Alpha" and "Z Transparency"
If you want the image to have precise dimensions, the best choice is "Plane dimensions: Dots/BU)": it allows you to determine the dimensions starting from the pixel size (eg: 1920 x 1080px at 100 Dots/BU -> plane dimensions: 1.920 x 1.080 BU)

Pan and zoom in Node Compositor

Here a possible node compositing:


How to change the Shadow darkness in eevee with HDR map?

I usually use a sun lamp aligned with HDR main light source, then I lower the HDR light power. The result is quite different from that obtained with Cycles, but somehow it is satisfying, at least for me.


Try using update methods.  Changing the dir would be the time to populate the list, changing the enum ... run some other code.  A lot of the code in the items callback can then be removed.

import os
import bpy

preview_collections = {}

def enum_previews_from_directory_items(self, context):
    pcoll = preview_collections.get("main")
    if not pcoll:
        return []

    if self.my_previews_dir == "": # use better default
        # put some code in here to populate default list
        print("MAKE A NEW THUMB LIST HERE")
        newlist = []
        '''
        # a list of items with name, filepath to image, and unique i

        thumb = pcoll.load(filepath, filepath, 'IMAGE')
        item = (name, name, "", thumb.icon_id, i)
        newlist.append(item)
        '''
        return newlist

    return pcoll.my_previews

class PreviewsExamplePanel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "Previews Example Panel"
    bl_idname = "OBJECT_PT_previews"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "object"

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

        row = layout.row()
        row.prop(wm, "my_previews_dir")

        row = layout.row()
        row.template_icon_view(wm, "my_previews")

        row = layout.row()
        row.prop(wm, "my_previews")

# We can store multiple preview collections here,
# however in this example we only store "main"

def preview_dir_update(wm, context):
    print("wm.my_previews_dir = %s" % wm.my_previews_dir)

    """EnumProperty callback"""
    enum_items = []

    wm = context.window_manager
    directory = wm.my_previews_dir

    # Get the preview collection (defined in register func).
    pcoll = preview_collections["main"]

    print("Scanning directory: %s" % directory)

    if directory and os.path.exists(directory):
        # Scan the directory for png files
        image_paths = []
        for fn in os.listdir(directory):
            if fn.lower().endswith(".png"):
                image_paths.append(fn)

        for i, name in enumerate(image_paths):
            # generates a thumbnail preview for a file.
            filepath = os.path.join(directory, name)
            thumb = pcoll.load(filepath, filepath, 'IMAGE')
            enum_items.append((name, name, "", thumb.icon_id, i))

    pcoll.my_previews = enum_items
    pcoll.my_previews_dir = directory

    return None

def preview_enum_update(wm, context):
    print("wm.my_previews = %s" % wm.my_previews)
    return None

def register():
    from bpy.types import WindowManager
    from bpy.props import (
            StringProperty,
            EnumProperty,
            )

    WindowManager.my_previews_dir = StringProperty(
            name="Folder Path",
            subtype='DIR_PATH',
            default="",
            update=preview_dir_update,
            )

    WindowManager.my_previews = EnumProperty(
            items=enum_previews_from_directory_items,
            update=preview_enum_update,
                )

    # Note that preview collections returned by bpy.utils.previews
    # are regular Python objects - you can use them to store custom data.
    #
    # This is especially useful here, since:
    # - It avoids us regenerating the whole enum over and over.
    # - It can store enum_items' strings
    #   (remember you have to keep those strings somewhere in py,
    #   else they get freed and Blender references invalid memory!).
    import bpy.utils.previews

    pcol = preview_collections.setdefault("main", bpy.utils.previews.new())

    bpy.utils.register_class(PreviewsExamplePanel)

def unregister():
    from bpy.types import WindowManager

    del WindowManager.my_previews

    for pcoll in preview_collections.values():
        bpy.utils.previews.remove(pcoll)
    preview_collections.clear()

    bpy.utils.unregister_class(PreviewsExamplePanel)

if __name__ == "__main__":
    register()

You can get fancy with the update methods using the methods outlined here https://blender.stackexchange.com/a/39624/15543


Find Blender PNG (or other format) Metadata in Adobe

I just tried XNViewMP and it seems to be able to read Blender's metadata on both JPG and PNG Files.

JPEG seems to be using several comment fields, as opposed to PNG which uses dedicated ones for each information. It does save a File field with the name of the original Blend file it was rendered from, so if you had them saved under different locations while rendering from different computers you should be able to identify which files were from the wrong file from there I think.

XNViewMP has some search functionalities, maybe it can search EXIF info, not sure. Anyway it uses EXIFTool to extract this information, so if that fails maybe you could go there directly if XNView doesn't work for you.

Edit: Just to be clear, in XNView, open your image view and under view mode while previewing the image file right click on the image and select Properties then check the ExifTool tab


Trying to select objects by name with script, don't understand this behavior

The script is setting the location of whatever object is active when the script is run.

bpy.ops.object.select_pattern(pattern="my_Cube")

assigns to the  context selected objects list.  This is the list of all objects in the scene whose select property is true (obj.select).  Using "my_" as a search string for the op would select all your "my_" objects.  The operator setting one as active is somewhat meaningless. Use

monkey = bpy.context.selected_objects[0]

to assign the first of the selected objects list,  after running that operator.

The context active object,  is best set using

scene.objects.active = obj

after running an operator that sets active object.

Suggest replacing all the annoying operators  with API calls something akin to:

import bpy

context = bpy.context
scene = context.scene

for name in ["Cube", "Cone", "Lamp", "Suzanne"]: # not a my_ fan 8^)
    obj = scene.objects.get(name)
    if obj:
        obj.location = (5, 5, 5)


How to pause a video animation in video editor

You would have to split the strip using Shift+K, then ...
just grab the right end of the left strip with your cursor and move it to the right. Then the last pic will be shown as long as you dragged the right edge.


It's controlled based on the window when you save your startup .blend.

To make it default to maximized:

Maximize the window.
CtrlU> Save Startup file, or File Menu -> Save startup file.

Note that if you make any  other changes (not including the splash screen), they will be saved as defaults as well.


How do I make dynamic 3D-printable hair?

Blender 2.80, add hair at a reduced count, comb it out, go to modifier then convert.
Then place the origin in a center point of the head. In edge, select all, "A". Now "E" for extrude, then "S" for scale, making face. Now in object mode add the modifier for solidify.

Takes some playing around. Maybe shrink a sphere to this. depends.
 Shrink works pretty good for body mesh expressions on Manuel Bastioni models. Nice clean, crisp slice, I always delete behind the eyes and internal mouth.


Modifying blend weights without "painting"

In the right (N) panel in the 3D view, there's a section called "Vertex Weights". It lists all the weights the active vertex is assigned to, and you can change any of them here.

Note that this only works for the active vertex, not all the ones you have selected. If you want to assign the same weight to a group for all the selected vertices, go to the Mesh tab in the Properties panel, go to the Vertex Groups section, find your group and set your weight, and hit Assign.


There is an addon for blender available at https://github.com/mutantbob/blender-letterbox which can be used to quickly add and configure the necessary Effect Strip.

After you have installed this addon from the .py file (instructions) you can either use the Spacebar menu to invoke the letterbox operator, or find it in the Strip menu of the VSE panel.


To store reusable poses you can use pose library this would still require a rig to restore.

When you export to e.g. to a .obj-file you could store the mesh in different fixed poses without the armatures.


Why is my animation choppy when I render it?

This can happen when fast moving objects result in a large difference between consecutive frames.
For reference, here's what my test scene looks like at 24 fps without any motion blur:

To fix this, you have a couple options:
Increase the framerate
Increase the framerate, adding more frames while keeping the same run time.
AFAIK youtube will play high framerate videos at a reduced framerate at lower user-set quality levels, so this may not be an ideal solution for youtube (the results may not be the same for all youtube quality settings).
Here's the same scene at 60fps (click the gif to see a better version):

Add some motion blur
Add some motion blur to smooth the transition between frames
See the manual for details on how to use motion blur in blender internal and in cycles.

Or both
Of course, you can do both at once too ;)
Again, click the gif to see it in a video format..

Unfortunately gifs make terrible examples when showing framerate settings and SE doesn't support embedding of other formats. Click on any of the gifs to see it in a video format.


You missed at least two things while following the tutorial.

At 11:15 Steve explains that you have to set the Array Modifier to Fit Curve. Your screenshot shows you've set it to Fit Length.
The second thing is, after adding the Subdivision Surface Modifier he explains why it doesn't look smooth enough yet and at 12:25 he enables the option Merge in the Array Modifier.

Maybe these two things might help to make it look right.


I would start with a Voronoi texture as displacement map to get the "pebbles", then disrupt that texture with other kinds of noise.


This case is pretty basic modeling stuff, so I will not go deeper in simple details and just show you an overview not to write full blown tutorial here (it's not place for this). If this is your first day you will need to know some starter pack things like:

Edge Loops and Edge Flow in general (tris, quads, ngons, poles and such),
creating, joining, cutting (Loop Cuts), extruding faces,
adding simple modifiers (Mirror, Subdivision Surface, Curve).

Everything is here, on Blender Stack Exchange as well as on YouTube or any other place with Blender resources (there is topic with them here too).

  I'm trying here some new answer technique, so be gentle. I'll expand
  this answer as much as OP will need it.

Overview:

Start with simple Plane at extrude one edge along green curve 9 times (to get 10 faces).
Add Mirror Modifier with Clipping checked.
Fill in faces in the middle of paddle (I don't know how this rubber surface is called).
Extrude bottom face to have a handle.
Add Subdivision Surface Modifier.
Select all and extrude it to gave depth to paddle.
Add Loop Cuts along green curve (the same from first step) and the short one at the bottom.
Add Bezier Curve.
Add Curve modifier for paddle. Important! It should be above Subdivision Surface.
Move the paddle along Curve to adjust it.
Edit Curve to give it bend.

In the blend file, on layer 2 you have 3 models of paddle to study them.

Blend File:

Temporary link (Blend Exchange giving some error with URL):

paddle.blend


What is the max size of a scene in Blender?

You need to set clipping limits for 3D view and for camera:


My human mesh twists strangely while moving armature

https://blender.stackexchange.com/a/34858

hope this helps im pretty sure its a issue with the bones axis rotation i was have a similar issue  all in all this video helped me more then anything

https://www.youtube.com/watch?v=dYiAd_08-0k&t=77s


Select the lamps you want to share the same data, hit Ctrl+L and choose object data. The corresponding lamps will now always copy each others settings.


That could happen if you are viewing the render result. Look at the bottom of the UV/Image Editor and see if it says “Render Result”.  If that is the problem, just click the X to the right of the image selection box or select another image and you should be able to see the unwrapped pelt.


Can Freestyle draw lines when an object is behind a transparent plane?

Visibility is computate without considering textures alpha.

From the a Blender reference manual's page on the topic, one of the known limitation is:

  Transparent faces are treated as opaque faces

Blender is currently (2.76b) not able to distinguish transparent surfaces from opaque surfaces, I would guess it will unlikely be able to use the alpha channel of a texture the way you planned.

A possible workaround for your particular situation may be to separate the freestyle render layer, move all the object that could occlude the freestyle lines on a separate layer and exclude it from the freestyle render layer.

Masking the layer would be the perfect option, but sadly is currently another of the known limitations:

  Layer masks do not work with Freestyle.

'Suzanne in Hell'

In the image above you can see how the selected plane is on the layer 10 (the yellow dot in the layer selector), which is the same layer not highlighted in the freestyle render pass (just behind the cursor).

Next step is to hide the lines behind the "solid" texture of the plane. In this example I used the Z channel of the first render layer:

With a "Greater Than" Math node filled with an appropriate value (must be animated if the camera is moving fowanrd and backward) I isolated the part of the scene far away from the camera and used this mask as a factor form alpha mixing the layers.

Note: Z-pass is not anti-aliased; in a the previus scene this doesn't reperesent a big a problem, but, if needed, you can use in the same way the Mist pass (which is anti-aliased, but take a few more steps to be set up)


When printing an Object (with Cura) the Hole disappears

You have geometry made out of a few separate closed volumes that are overlapping:

That is definitely not a good idea. You should have one continuous volume per object. I can only guess how your printing process works, however the printer will probably need a continuous volume so the software is probably trying to automatically guess what it is using Boolean operations that do not work well with overlapping geometry that is also present in the model. You should simply model the object as a single continuous volume that has one continuous surface that does not overlap with itself. You should not have any overlapping geometry(vertices, edges or faces), there should also be no holes or non-manifold geometry in your models if you wish to avoid problems when 3d printing. In some cases printing software may fix the issues automatically, but obviously, if you wish the process to work every time as expected, you should ensure the geometry is tidy and suitable for printing in the first place.


How do I select vertices by material slot in Python?

Okay, I figured it out (and I'm dumb and if there is a way to delete these questions you answer yourself I would).

All I had to do was to set the active index of the material and then do a material slot select (as I already had).  So this works:

for num, m in enumerate(imported.material_slots):
    ...
    bpy.context.object.active_material_index = num
    bpy.ops.object.material_slot_select()

Now just to make a new material, assign the faces to it, and delete all the old ones, but I think I have that.


Download a copy of 2.78RC2 - the boolean modifier in 2.78 has a new BMesh solver that looks to give the results you are after.


Curves not showing direction in edit/object mode

2D curves have no normals.
For 3D curves enable show normals in the overlays section.


How to see Cycle's material transparency in 3D View

I think I've figured this issue out. I'm in Blender Cycles.

To see the transparency, make sure you're in the "Material" view in your viewport.

With your image-plane selected, go to the Material tab.

Toggle down "Settings" at the very bottom. Make sure "Viewport Alpha:" is set to something other than "Opaque". I find "Alpha Clip" and "Alpha Blend" worked well for the .png image I was using.

Hopefully this answers your question.


This happens because you haven't applied scale , so to apply scale ,press space bar search for Apply Object Transform , click the option then go at the tool-bar then under the tool-shelf and select scale.
then repeat the steps you are doing in your question.
Note: you should be in object mode to be able to search for Apply Object Transform.


Script to separate shared vertices that have different UV's, normals and colors

As you noted most data is stored per-face in blender; in the UI it is called "face corner data", the API calls it "loops".

This is fairly simple: just loop over the polygons, get all vertex data you need, pack it into hex, append the vertex to a list if it is a new one (using a dummy vertex to avoid duplicating too often due to inconsistent normals) and finally index the polygon's vertices in the vertex list to get the polygon's exported indices.

#output
mesh_vertices = []
mesh_triangles = []
#used to ignore the normals for checking equality
dummy_vertices = []

for polygon in me.polygons:
    tri=[]
    for loop_index in polygon.loop_indices:
        vertex_index = me.loops[loop_index].vertex_index
        co = me.vertices[vertex_index].co
        no = me.loops[loop_index].normal

        bfb_vertex = pack('3f',co.x, co.y, co.z)
        bfb_normal = pack('3f',no.x, no.y, no.z)
        if me.vertex_colors:
            bfb_col = pack('4B',int(me.vertex_colors[0].data[loop_index].color.b*255),
                                int(me.vertex_colors[0].data[loop_index].color.g*255),
                                int(me.vertex_colors[0].data[loop_index].color.r*255),
                                int(me.vertex_colors[1].data[loop_index].color.b*255))
        bfb_uv = b''
        for uv_layer in me.uv_layers:
            bfb_uv+= pack('2f',uv_layer.data[loop_index].uv.x, 1-uv_layer.data[loop_index].uv.y)
        #we have to add new verts also if the UV is different!
        if bfb_vertex+bfb_uv not in dummy_vertices:
            dummy_vertices.append(bfb_vertex+bfb_uv)
            mesh_vertices.append(bfb_vertex+bfb_normal+bfb_col+bfb_uv)
        bfb_vert_index = dummy_vertices.index(bfb_vertex+bfb_uv)
        tri.append(bfb_vert_index)
    mesh_triangles.append(pack('3h',*tri))


Particles rotate unwillingly on a surface along normals using Particles hair

Use Emitter instead of Hair

Check Rotation/Normal to align the particles to the Face normals
Disable Physics
Check Unborn and Dead to make sure the particles don't appear/disappear


I suggest a timeout implementation.

Use a timer property to let the BGE count the time for you (timer properties always count upwards).

I suggest to use states to toggle between "ready" and "blocked" status.

State "ready".

In this state the operation can be activated at any time.

When the operation gets activated, you switch the state to "Blocked" and set the (negative) timeout value.

State "blocked"

In this state the operation should not be available.

All you do is wait until the timeout happens. You do this by measuring if time gets positive. When it does you switch to state "ready".

Conclusion

There are other ways to implement timeout. This one is a pretty efficient one as there is not really much to do rather than waiting on the events to happen. By using states you clearly separate the logic of both states.

I hope it helps


Is there any way to make X Mirror respect delete?

I think Carlo's option makes sense, though it might need more explaining. The X- mirror splits down the center and mirrors in the negative X. Any changes you make in the negative, be that deleting or adding vertices will be updated in the positive X after you have applied symmetry. It does not work if you flip the process and work on the positive X first as the negative X will not be updated.


UI defined custom properties.
If you mean those defined by the UI

Example, two custom properties on default object
Iterate over custom properties without searching?
Their names via keys
>>> C.object.keys()
['prop', '_RNA_UI', 'prop1']

or via items to get key, value pairs
>>> for k, v in C.object.items():
...     print(f'ob["{k}"] = {repr(v)}')
...
ob["prop"] = 1.0
ob["_RNA_UI"] = <bpy id prop: owner="OBCube", name="_RNA_UI", address=0x7fa661ad48c8>
ob["prop1"] = 1.0

The _RNA_UI member holds all the info re min, max, description for layout, when not defined with a bpy.props. (If defined via bpy.props and non default the data is saved as a custom prop of same name)
Finding the source for "API Defined" custom properties
When should custom-properties be used instead of 'bpy.props'?


Baking objects always yields a black image

You have to recalculate the Normals of your ground, I guess they were messed up: Enter in Edit mode, select all and ctrl N, then Bake again.


What is the easiest way to curve a cuboid?

Wouldn't deleting a few faces from a Mirrored, Solidified, Subdivided hemisphere, or half round-cube, make an easier starting point than caving in the front of a full sphere?

Then duplicate some faces to new objects, and Solidify those the other way..

You can always randomise it later, maybe sculpt with a cloth brush..


You have Custom Normal Data assigned to this mesh.

Go to Data Tab > Geometry Data > Clear Custom Split Normals Data


Any way of serializing Blender cycles materials data?

There is the rna_xml module, which produces pretty verbose xml

from rna_xml import rna2xml

rna2xml(root_node="MyRootName",
        root_rna=bpy.data.materials['Material'].node_tree)

produces (not full output).  There is also an rna2xml routine.  To output to a file use rna2xml(fw=f.write, ...) where f is a file.

<MyRootName>
  <inputs>
  </inputs>
  <links>
    <NodeLink is_valid="TRUE"
              from_node="ShaderNodeBsdfDiffuse::Diffuse BSDF"
              to_node="ShaderNodeOutputMaterial::Material Output"
              is_hidden="FALSE">
      <from_socket>
        <NodeSocketShader name="BSDF"
                          identifier="BSDF"
                          is_output="TRUE"
                          hide="FALSE"
                          enabled="TRUE"
                          link_limit="4095"
                          is_linked="TRUE"
                          show_expanded="FALSE"
                          hide_value="FALSE"
                          node="ShaderNodeBsdfDiffuse::Diffuse BSDF"
                          type="SHADER"
                          bl_idname="NodeSocketShader">
        </NodeSocketShader>
      </from_socket>
      <to_socket>
        <NodeSocketShader name="Surface"
                          identifier="Surface"
                          is_output="FALSE"
                          hide="FALSE"
                          enabled="TRUE"
                          link_limit="1"
                          is_linked="TRUE"
                          show_expanded="FALSE"
                          hide_value="FALSE"
                          node="ShaderNodeOutputMaterial::Material Output"
                          type="SHADER"
                          bl_idname="NodeSocketShader">
        </NodeSocketShader>
      </to_socket>
    </NodeLink>
  </links>
  <nodes>
    <ShaderNodeOutputMaterial type="OUTPUT_MATERIAL"
                              location="300 300"
                              width="140"
                              width_hidden="42"
                              height="100"
                              dimensions="178.889 116.333"
                              name="Material Output"
                              label=""
                              parent="NONE"
                              use_custom_color="FALSE"
                              color="0.608 0.608 0.608"
                              select="TRUE"
                              show_options="TRUE"
                              show_preview="FALSE"
                              hide="FALSE"
                              mute="FALSE"
                              show_texture="FALSE"
                              shading_compatibility="{NEW_SHADING}"
                              bl_idname="ShaderNodeOutputMaterial"
                              bl_label="Material Output"
                              bl_description=""
                              bl_icon="NONE"
                              bl_static_type="OUTPUT_MATERIAL"
                              bl_width_default="140"
                              bl_width_min="100"
                              bl_width_max="320"
                              bl_height_default="100"
                              bl_height_min="30"
                              bl_height_max="30"
                              is_active_output="TRUE">
      <inputs>
        <NodeSocketShader name="Surface"
                          identifier="Surface"
                          is_output="FALSE"
                          hide="FALSE"


Creating floors for an SVG floorplan converted to 3D and exported for use with Unity

Maybe just add planes on top and bottom? Nice polycount, easy to hide in Unity if you need so.


When I right click while in edit mode, the context menu doesn't appear

go to Edit>Preferences>Keymap
In the searchbox type: Call menu
Then have a look in the search results for "Mesh Call Menu". And check what key you have assigned for it. Should be "Right Mouse" if you want it like this.


eyes not moving 100% with head / eyes lagging behind

I took a look at your file. Rigging eyes is complicated. I think the problem had to do with either:

The eye bones not sitting directly on the origin of the eyeballs...

OR

..that the head bone (spine.004) Y axis didn't sit on the same location as the origin of the eye balls but I'm not sure which or if any of those were what were causing the eyes to yaw off target. It always gets really complicated when you're working with many different bone rotations and origin points etc.

OR

That the eyes were a single object and needed separating. As the front of the head moved from side to side, the eyes only moved in accordance with the rotation of the head bone tail and not at the same height and angle as the eye sockets.

Now, I think it works perfectly but you let me know if it doesn't work.

If you want to follow a good tutorial on it, I use a similar method to this guy. This video is great :)
https://www.youtube.com/watch?v=-9GDj8_bx6M

Here you can download your edited rig:
https://www.dropbox.com/s/5xbykg8brg5msn2/human_male_EDIT.blend?dl=0

Let me know if you can download that file and I'll upload it to another sharing website.

Hope that helps :)


How to use presets for operator properties?

You can enable presets for an operator using the PRESET option.

eg:

class SomeTool(bpy.types.Operator):
    bl_idname = "object.some_tool"
    bl_label = "Some Tool"
    bl_options = {'PRESET'}

    # - snip -

The preset directory will be set based on the operator name and created on demand.


Sverchok

You can build the geometry starting from the curves interactively by accessing their vertex coordinates with the Sverechok add-on.

As you can see in the image sequence below, this will allow you to move each curve in object mode or it's control points in edit mode and transform the resulting surface by simply updating the script.

For the following, example I choose to build an 3-points-arch for the sake of semplicity as Sverchock has a built in node that is able to create an arc from a given points triplet, but with more effort you can surely achieve whatever result.

On the right of the image below you can see three Object input nodes, one for each curve, followed by a Matrix apply node to get the absolute coordinates of the vertices. As they are stored in separate lists, you'll have to join them. By enabling Mix option we esure that all the first vertices of each curve is bundled with the other in the array.

Then you just have to set the arbitrary resolution of the arc and place an output node (Viewer Draw in this case).

In order to get a full surface we should add some nodes. In this case I picked a Cylinder's polygons indices after filtering out the faces that were connecting the two curves on bottom and joining this data with the vertices coming out from the 3 Point Arc node.

The images above are showing a blue surface because it's just the add-on preview, no "real" geometry has benn created yet, as before we must define also the edges of the surface.

As did for the polygons, I filtered out the edges (they need some further math tricks) and then added a Bmesh viewer to bake the surface in the scene.

Here's the final node setup:

Note:
The nodetree is expecting curves made by the same amount of vertices (there is a node where you should input that). Keep them with the same number of control points & resolution. Same thing if you choose to input meshes instead of curves.


Smooth deformation of rigged vertex group

Welcome to Blender StackExchange!

What's going on here is that the vertices you have painted only have weights that move them, and none trying to hold them in place. When weight painting, you're essentially telling blender how much a certain bone will affect a vertex. Think of it like a tug-of-war. If there's only one person pulling, it doesn't matter how strong they are, they're going to win.

Thus, to solve this problem, you'll need to add a bone (say a head bone) that the stationary parts of your model are assigned to. Then it's just a matter of blending the two weights. A trick for this is to move the bones to a point where it doesn't deform well, then paint it until it does. Then you can reset the bone (Alt+G and Alt+R). You may find the blur brush handy as well, as that can eliminate the sharp transitions between colors that you see in the third image.


The lower arm mesh is influenced by the upper arm bone. You need to do several things:

First put your Armature modifier above the Subsurf, enable Preserve Volume, plus I don't think you need 2 for Viewport Subdivisions but it's a detail.
Your topology needs to be aligned on your bones and also you need to make sure that it will allow your elbow to bend smoothly, so move your elbow edge and bevel it.
Select the armature then the object, switch to Weight Paint mode, in the N panel > Tool, choose Blend > Subtract or Mix depending on if you want to subtract or add influence, in the Options only keep 2D Falloff so that you'll be able to paint through the mesh.
Select the upper arm and paint its influence so that it doesn't cross the elbow, same for the lower arm.
Move your bones to test.


Just to illustrate my comment :-).
Simply run an image texture through the Emission node.


You should be able to do this be adding a function to:

bpy.app.handlers.render_pre.append(function_name)

This way whatever function you name will be called before the render happens. Here is a little info on it: link

Make sure your function takes self as a parameter, like so:

function_name(self):
    print("Test")


Na, it's fine... you just accidentally got your smooth stroke enabled. Disable it and you will be fine.


Force fields affecting selected rigid body objects

This appears to be similar to the behavior described.

In this scene, the wood and metal cubes are affected by gravity, but only the metal cubes are attracted to the red cylinder.

In Blender 2.76, this can be accomplished using soft bodies instead of rigid bodies.

How to create this scene in Blender 2.76

Start with a new scene.
Add a plane, scale it.
In the physics tab, add collisions. Set the soft body damping to 0.

Move the cube up.
Go into edit mode. Select all vertices.

Subdivide the mesh. This will ensure there are vertices and edges for collision detection.
Create a new vertex group called 'Group'. Set the weight to 0. Assign all vertices to the vertex group. Settings later will use this to allow the soft bodies to move.

Go back to the object mode. Setup the soft body physics.

With the cube selected. Go to the physics tab. Select 'Soft Body'.
In the 'Soft Body Goal' panel, set the vertex group to 'Group'. This is the group assigned earlier.
In the 'Soft Body Edges' panel, select 'Stiff Quads', set the 'Push' value to 0.999, the 'Pull' value to 0.999, and bending to 0.100. This will make the soft body behave almost like a rigid body.
Select the 'Edge' and 'Face' collision options. This will help make the collisions more like a solid collision.

Test the simulation by pressing the play button on the timeline. You should see the cube fall to the plane, wobble a little, then stop. This indicates that the collisions are working and that the cube behaves like a solid.
Select 'Collision' physics. This will let the cubes collide with each other.

At this point, the cube is duplicated. One cube will be affected by force fields and the other will not. This will simulate the iron and wood.
Duplicate the cube. Rename the duplicate to 'Wood-Cube'.
Select the 'Wood-Cube', in the physics tab and the 'Soft Body Field Weights' panel, set the 'Force' to 0.000. This causes the 'Wood-Cube' to ignore force fields.

Add an empty to the scene. Move the empty to the edge of the plane. In the physics tab, select force field. So the force field attracts objects, set the strength to a negative value. This examples will use -10.

This has all of the elements for the simulation! The 'Cube' will be attracted to the empty's force field. The 'Wood-Cube' will not be attracted, but will interact with 'Cube'.
To troubleshoot, try different force strengths and clearing the soft body caches.

The file used to generate the animation above is located at


It's not working properly because you simply joined the two cubes. Now they are a single object, but in Edit Mode still two separate meshes with their own volume, but overlapping in some parts.
In order for the Boolean Modifier to work, the volumes you want to subtract from the landscape have to be either separate without overlapping or you have to create one continous volume for the overlapping cubes.
Since the overlapping is necessary in your case, you have three options, all require you to separate the cubes beforehand and make them two objects again:

Work destructively by first subtracting one cube, apply the modifier and subtract the second cube.

or:

Give the first cube a Boolean Modifier and join it with the second cube by setting it to Union, then choose the first cube for Difference in the Boolean Modifier on the landscape.

or:

Maybe the simplest way: put two Boolean Mdifiers on the landscape, choose one cube for the first modifier and the other cube for the second modifier.


Yes, you can in many ways. You can just mix RGB:

Or similarly you can mix shaders (here the effect is the same, but with different Principled BSDF settings it would differ):

Or you can do something more interesting:

If you have some specific textures in mind and a specific way to merge them, it would be good if you described them in your question. A texture with scratches could be added based on it's alpha channel for example.


Change material on part of object with other overlapping object

You can create 2 overlapping cubes. Create somewhere a third cube that will be the boolean object and make it invisible in render. Give your 2 first cubes 2 different colors, give them both a Boolean modifier with the third cube as Object. For the orange cube, choose the Difference option, for the blue one, choose Intersect.


How to scale vertices in only top view but not impacting how they look in front view?

select the vertices, edges or faces you want to scale
use axle restrictions.

press to individually restrict:

x
Y
z

If you wish to restrict 2 axes, press:

SHIFT + Z to scale in X, Y, and restrict Z
SHIFT + X to scale in Y, Z, and and restrict X
SHIFT + Y to scale in X, Z, and restrict Y


What does the "Camera Clip" checkbox do in the "Background Images", "Movie Clip" tab do?

The Camera Clip option is referring to the active movie clip for the scene. This would normally be the clip that you are using for camera tracking.

In the scene properties you will find the setting for Active Clip. This active clip for the scene is the one referred to by the Camera Clip setting. The available clips are the clips that have been loaded into the movie clip editor for camera/object tracking.

While the same clip can be chosen in the background settings, by using the scene's active clip you can use the same setting in multiple views and change them all in one place.


The hair of my character gets left behind

Go to modifiers section and rearrange your particles modifier. I mean place it before or after armature modifier. One of it should work. Hope that helps!


How to use the Alt + Right click in edit mode in Linux

Keyboard shortcuts on the OS override those in Blender.

Two possible solutions:

Change the keyboard shortcuts on blender and avoid conflicting key combinations.

The main disadvantage custom shortcuts is that it's hard to follow tutorials or other help. If you work with blender on other computers your shortcuts will not match. Resetting to factory defaults will also result in the loss of your custom settings (unless you save them to a file).

Reassign the keyboard shortcuts on the OS using key-combinations that are not used in blender.

(The way I deal with it is by re-assigning the Linux keyboard shortcuts so that Alt of Ctrl keys are not used by the OS, but use the super (windows) key instead).
On Linux Mint open the system settings and navigate to "Windows".

and select the super key to move or resize windows:

You might have to restart Blender for all Alt-related keyboard shortcuts to work reliably.


Same mesh displayed differently on different machines

In Windows you're in weight-paint mode and in Ubunto you're in wireframe view (in object mode).  If you want to change the Ubuntu version, hover over the 3D view and hit Ctrl+Tab to switch modes.  Alternatively, use the menus at the bottom of the 3D view to switch between modes (see screenshot).


index number by vertices? in animation nodes.. is it possible?

Setting the index was not necessary, solved by adding an object list I/O to the loop node :)


When you go to Outliner, right click over Material item and choose Resync Library Override it brings driver to work, but after reopening file it is not working again and I had to Resync again.
From video it looks like you are using 2.92 in this version when saved&reopen (or your Revert), Material became Linked (chain icon) for some reason, that is why driver is not working. It is the same issue like I noted in your previous Q with Action. You have to right click on Material item and manually Add Library Override first (so it became chain with arrow icon). Than Resync LO.

In 2.93 your driver is not working from beginning, even in this version Material has LO icon it is not working anyway and Resync LO is needed as well.
Note: I have zero experiences with LO as mentioned, but it seems to me like a bug or not working feature since LO is very new to blender, so it can be just a corner case yet in development. Try to post it as a bug and mention bug report link here in a comment, so others can follow developers statement of this thing. Thank you

In latest experimental build 2.93 I noticed under User Preferences > Experimental ... there is Override Auto Resync with a link to https://developer.blender.org/T83811 so you can get more info. But seems like not covering your issue yet (from what I tried - still manually).
If someone smarter here can explain more.


What is the difference between handlers render_post and render_complete?

render_post runs after each frame is rendered. If you have 10 frames, this event will fire 10 times.

render_complete runs only once, after all frames were rendered (when the entire animation's rendering process is complete).


Make sure you first have applied transforms (Ctrl+A) , and then make sure you have your object center on the center line of the grid. You can do this by snapping the cursor to the object's center (Shift+S > Cursor to Selection) in Object mode and then snapping the object to the cursor with Shift+S > Selection to Cursor in Edit mode.

Then in Edit mode move your geometry to align to where it should be on one side of origin point by X axis; the Mirror modifier should show the mirrorred part on the opposite side. If mirrored part has to be connected to original enable Clipping in Mirror modifier settings.


Why are objects rendering black even with texture (both cycles and BI)?

You can fix it by adding an attribute node to assign the UV map you intent to use:

I made minor changes in the node editor:


Cycles is a ray tracing renderer.
Can use different tracing strategies (under integrator option):

Path tracing: pure path tracer.
Branched path tracing: path tracer with branching on the first bounce.

It uses Monte-Carlo for sampling, that means repeated random sampling.

Soon Metropolis Light Transport should be also available which is a variant to Monte-Carlo, it uses Bidirectional path tracing and Metropolis sampling.


Is there a way to have vertical stripes on all timelines?

The timeline will highlight between the start and end frame. There is a preview range option that allows a second set of start/end frame values to be used, when this is enabled the one frame range is highlighted in each time based editor. I don't know of any other way to highlight sections of the time based editors.

The only other option would be using markers, these are named triangles shown at the bottom of each timeline.


Shrinkwrap Modifier Doesn't Conform After Having Geometry Follow Profile

Change the order of your modifiers.  Shrink Wrap first then SubSurf. See which one you like better.


Unwrap torso part creates a messed up UV map

Fiddeling around and examing a large number of related topics I found the solution by myself.

It seems the mesh is pinned (to whatever) and has to be freed before.

Select the mesh in edit mode
Go to UV mode/window and select all (A)
Unpin the mesh in UV mode (Alt P)
Redo the unwrap in UV mode (E)

Voila!


Multiple objects being edited in edit mode

I think they have linked data, they share the same mesh and whatsoever you are doing to one applies to the others. So either press U and select Object & Data

or press the number that shows how many objects share the data (on the right in the red circle)


Re-baking as .png 16 bits format solved the issue (was .tga before)


Applying Mirror Modifier with Shape Keys on a rigged Model

For anyone who still wants to know (P.S. I did this in Blender 2.79):

This doesn't fix it entirely, but....

You can remove the mirror modifier,
and duplicate and then reverese the vertices onto the other side.

(E.g. move 3D cursor to centre of mesh, duplicate verts, and scale along x-axis by -1 around the 3D cursor)

Some of the shape keys might be close enough.
But some may need tweaking.

Depending on how lucky you are, this may or may not be easier than removing shape keys, applying mirror modifier, and re-do-ing all the shape keys again :/


Blender 2.90 includes an experimental Wayland backend when compiled with the corresponding flag. You can view which flags blender was compiled with when executing blender --version and you should be looking for WITH_GHOST_WAYLAND.
BTW you can easily test if an application is running under XWayland by starting xeyes and moving you mouse cursor above the window. If the eyes are still following the cursor the application uses XWayland


Failed to load CUDA kernel: rendering crashes after few hundreds of iteration on GPU

As @RobertGützkow mentioned, it was because too many files were opened. Blender was unable to open the CUDA kernel after it reached the system's maximum file descriptor limit. ulimit -n gave me 1024. I increased the limit by ulimit -n 70000 and the error disappeared.


Get access to generator modifier x values for drivers

Looks like you cannot access this property, but there is a workaround by scripting the generator yourself and by adding 2 custom ID properties to the object to control it.

import bpy

class Panel(bpy.types.Panel):
    bl_label = "Custom Panel"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'TOOLS'

    def draw(self, context):
        layout = self.layout
        layout.prop(context.active_object, '["offset"]')
        layout.prop(context.active_object, '["multiplier"]')

def register():
    bpy.utils.register_module(__name__)

def unregister():
    bpy.utils.unregister_module(__name__)

if __name__ == "__main__":
    register()


What causes striped visual artifacts in models?

Deepth coordinate during deepth testing made by graphic pipeline is the same.
1 has flipped normals + Z fighting.
2 is just Z fighting.
Here is more literature:
https://learnopengl.com/Advanced-OpenGL/Depth-testing
 Read "Z-fighting" in the middle of a page.


How can I find an specific F-Curve given an action name?

You need to use the fcurves.find(data_path, array_index) function. For example, we want to retrieve the F-Curve for the location’s Z channel, for an action named ActionName.

# Configuration
action_name = 'ActionName'
data_path = 'location'
array_index = 2

action = bpy.data.actions.get(action_name)
if not action:
    print('Action {} not found.'.format(action_name))
else:
    # Retrieve the specific F-Curve
    fc = action.fcurves.find(data_path, array_index)
    if fc:
        for kfp in fc.keyframe_points:
            print(kfp.handle_left)
            print(kfp.handle_right)
            print(kfp.interpolation)
            print('Frame = {:04}; Value = {}'.format(kfp.co[0], kfp.co[1]))


I downloaded and "installed from file" this script in 2.79:

https://raw.githubusercontent.com/lapineige/Blender_add-ons/master/Multi-Camera-Render/multi_camera_render_v2-1.py

Then, selected both (2) cameras and pressed the "multiple camera render" and it produced 2 images, as expected.

With the addon default settings (empty directory) those images were created in the blender folder itself (I use a zip blender version); selecting a folder on my desktop as "directory" they were created in that folder, as expected...


How to make water not pass through bottom of floating object?

You can create an object of a shape similar to your floating object (bowl, boat, whatever) but lower-poly. Then select your ocean object and add a Boolean Modifier. The Operation mode should be set to Difference, and the Object slot should of course be set to your low-poly boolean object. Normals must be facing the correct directions or you'll get unexpected results.

Here is a screen shot of my test doing this with a simple cylinder:

Now there are just a few more things to do.

Prevent this boolean object from being rendered.

You can do this by finding the object in the Outliner and turning off visibility for the render, and for the viewport if you like (although this makes it no longer selectable).

In my screen shot I have set the Maximum Draw Type to Wire, and that's why I can still see and select my boolean object. However this leaves it visible during viewport rendering, so to fix that I simply gave it a material with a Transparent shader (with the color set to white for full transparency).

Parent it to your original floating object, so it moves with it.

Pretty straightforward. Select your boolean object, then select your floating object and press [Ctrl P]. Set Parent to Object.

Fix possible issues with ugly shading on the geometry of your ocean where it touches the boolean object.

With your ocean object selected, navigate to the Mesh Tab. Check the box for "Auto Smooth". Also, in the Tools panel set the object's Shading to Smooth.


The objects data property contains the data used to define the objects appearance. For a mesh object that includes vertices, edges and polygons.

While vertex groups are stored within an objects properties, each groups vertex indices are direct indices into the objects data.vertices[] list. These are all kept in sync internally by blender so you don't have to be concerned, unless the mesh gets edited while you are accessing the data.

If you start with bpy.context.selected_objects you can export objects of type MESH. Then look at an objects modifiers list to find a modifier with a type of ARMATURE and get the object property from that to get the relevant armature.


Sliding an edge loop in an imported image distorts the image (blender 2.81)

In the tool menu for Loop Cut and Slide (after making a loop cut once), check 'Correct UVs' and it should work as you expected.


How to extrude while obtaining better topology?

You can perform the following steps to get a clean topology with the same shape.

Select the first face and extrude downwards.

Now switch to edge select and select the other faces and the outer perimeter.

Repeat the same technique shown in the last two steps.


It is not possible to limit the render time exactly. You must experiment with the number of samples to get an equal render time.


As long as you aren't going to be doing any really up-close shots of the windows, just use a plane with transparency. You don't even need an image. You can procedurally generate the texture. Mix an Anisotropic BSDF shader with a Transparent BSDF shader using a Brick Texture as the mix factor. To change the size, adjust the Scale: parameter.

Result:

If the renders are looking too dark/taking too long, you can add this to the node tree:


Increase brightness of HDR to light the scene, but keeping the background at a lower exposure

Use two nodes for the background, one to light the scene at the intensity you want and one with the normal exposure that is only seen by the camera:
Control the mix using a light path using Is Camera Ray.


Trying to figure out a proper way to Snap

Press . to change the center of manipulation to the cursor, center the cursor to the red vert, select the green vert, then size x 0


TRy going into edit mode on your mesh. Then, select the weird part and find out what bone you want to control it. Then in vertex groups click on the black arrow and remove from all the vertex groups. Then, click the group of the bone you want it on and click assign.


"Render Animation" doesn't refresh bone constraint to rendering frame in 2.8

I was having a similar problem.  My issue was I had one bone with a Damped Track constraint pointed at a another bone which had it's own Damped Track constraint pointed right back at the first bone.  It should have still worked since the tracking constraint didn't affect the location of either bone's head, but...  it apparently confused Blender anyway.  Ultimately, in order to fix the problem I had to create 2 more bones with no constraints in the same locations of the original 2 bones.  I could then have the original 2 bones point at those un-constrained bones.  In other words, having a constrained bone relying on another constrained bone can cause problems.


How can I subdivide an edge at a specific point on an axis?

You can edge slide a single vertex.  Select it and type GG and then move it:

But if the sloped line has endpoints that have the same x coordinates as the bottom line, there's another way:
Subdivide the top line into the same number of segments as the bottom line:

Each new vertex in the sloped line has the same X coordinate as the corresponding vertex of the flat line.
There are various ways to select the vertices you want to remove.  One that works is to select the vertex you want to keep and then use CTRL+I to reverse the selection:

next shift-left-click on each of the end vertices to deselect them:

Then type x and select 'dissolve vertices' to get rid of the excess:

and you're left with what you want:

Notice that I had both lines share an endpoint.  This isn't necessary, and what I suggest would work in your example, so long as the two endpoints have the same X value


How to maintain right angles while editing a rotated mesh?

This is happening because you're moving the loop according the its locals, which is not straight because your mesh is not straight--your mesh has its own locals (either an element that you added is making it this way, or you didn't make your mesh on the grid properly)--not according to the other points in respect to the loop. How do we know this? Because if you slide the loop G x 2, you find that this doesn't happen.

In orthographic view, you can see that there's an alignment issue of some sort at the very top (middle). There's a crease there to be specific (not easy to notice, I know). Check this by going into orthographic view from the front side (Numpad 5 for orthographic, and Numpad 1 for front) and look by the Z axis. Alternatively, look at Z-axis values of your edges.

The sign of not being straight (only noticeable at distances, generally):
(Note that if the lines were straight, this should never happen.)


Did you try dragging the connectors instead of clicking them?


Setting the material normally will only affect the active object, not all selected ones.

To fix this, change the material like you just did where it only affects one object, then press Control + L, and select Material, and it will copy the material to all other selected objects.

Hope that helps!


How to remove the 'Reload trusted' button when opening blend file

Have you tried activating "Auto Run Python Scripts" in the user prefs?

Setting this option, removed the "Reload Trusted" button whilst using add ons for me.


How to make a cylinder / pipe with slanted ends (like pasta penne)?

In edit mode select all the vertices and use the shear tool (shift+control+alt+S)


Where do I find the equivalent of Blender Render's texture slot panel in Cycles?

Switching to the cycles render and then to the blender internal render removes the texture slots. The video also mentions that they are using blender render and not cycles.


How to reverse the moving of timeline in blender

You are likely pressing the 'play backwards' button instead of the 'play' button. If not, check your frame beginning and ends. I'm on phone rn so I cant show a screenshot, but its pretty easy to find.


How to consolidate or collect all the texures used in a project?

One way is to go:

File > External data > Pack all into .blend.
Save the file (Ctrl+S) - this will actually pack the textures.
File > External data > Unpack All Into Files > Write Files to current directory.

This will create a folder containing all textures that were packed.


How to unattach an object and reattach it somewhere else in an animation?

Go to the last frame where you want small-cube acting as the child of big-cube.  Keyframe loc/rot/scale and the influence of your child-of constraint (at 1.0).

Advance a single frame.  With small-cube selected, use "apply visual transform" operation.  (From ctrl-a menu in object mode for me.)  Small-cube will jump; don't worry about it.

Set the influence of your child-of constraint to 0 and you'll see small-cube jump back to where it "should" be.  Keyframe loc/rot/scale and constraint influence (at 0.0).

Optionally, turn off snapping in your graph editor and move this frame's keyframes -0.99 in the graph editor's X axis.  This is to preserve smoothness of motion.

Go to the frame when you want small-cube to begin acting as the child of cylinder.  Transform small-cube to how you want it to look at this frame.  Create an additional child-of constraint, targeting cylinder, and set the inverse.  Keyframe loc/rot/scale and constraint influence of this second child-of constraint (at 1.0).

Go back one frame.  Apply visual transform, then set constraint influence (of cylinder child-of) to 0.0, then keyframe loc/rot/scale and constraint influence.

Optionally, move this frame's keyframes +0.99 in graph editor's X axis.

Make and edit whatever breakdowns you want in the period between the small-cube acting as the child of big-cube and the child of cylinder.

Optionally, after completing the animation of small-cube and big-cube and cylinder and anything they depend upon, select small-cube and use a "bake action" operation with "visual keying" and "clear constraints" to write the constraints to raw transforms.  This will prevent any issues arising from motion blur and will allow you to retime the animation to your heart's content.


How can I use a green screen to add a video onto a moving plane?

No need to use afterFX for this.
The idea is quite simple.
You use green, or some color that is not present in the scene, to create a matte (or mask) that can be used to combine other elements in the scene.
In the compositor connect the image that has the green element add a keying node, select the key color and the node will output Image and Matte separately.
Use the Matte to control the mix between the tracked plane and the image.

Or use just use the mask and feed the original image. This setup will avoid correlated alpha issues.


Why the knife tool can't be used on some of my faces?

It appears to be because you are trying to cut into the "virtual" geometry created by the mirror. You have set the Mirror modifier to display both sides as if they as edit-able, but the KnifeProject feature doesn't seem to take the mirrored geometry into account (but it is reasonable to expect that it should..)

the option with the green square let's you edit both sides, but not project onto both sides.

Other problems with your model:

You also have some issues with degenerate geometry (faces with zero area), and faces that you might not be aware of causing non-manifold geometry. Use

to look for hidden geometry, and in Face selection mode look for Dots on Edges, that's an indication that you have collapse or potentially  "invalid" geometry.

Additionally, the KnifeProject tool has a feature which can limit/extend the distance the cut goes into the geometry.

Is the different between these two cuts (cut from a different Viewing angle than shown so you can see the range of the cut)


Why do the faces in my model become checkered when rendering?

My blunder.  Even though duplicated objects were hidden in my layer control, they still showed in the render.  deleted them and issue has been resolved!


How to model a Coral or Sponge Structure?

I'm not sure you can get anything good with a bump map or procedurally, especially if you're supposed to make a "perfect copy", so I guess you'll have to make the mesh manually: create a cylinder, mirror it, use your picture as background to follow the shape, cut the holes profiles with the knife, extrude, add some edges with the knife to make a nice topology with quads, etc.


How to make objects clickable hyperlinks in WebGL?

First (if you haven't already), download the Blend4Web SDK and be sure to install it correctly. The SDK is different from the standalone add-on, so make sure you get the SDK (which includes the full-featured add-on, and also a lot more).

Set your render engine to Blend4Web.

Enable Blend4Web's Logic Editor and create a new node tree by clicking the [+] button.

In Blender's Node Editor, set the node tree type to Blend4Web logic, and select your node tree.

Make a node setup like this to instruct it to redirect to another URL when an object is clicked:

This node setup specifies that IF Suzanne (the monkey) is clicked, the redirect will happen, ELSE go back to listening for a click. That's why the "Miss" output routes back into the "Previous" input in a loop.

You can click the Fast Preview button on the right of the 3D Viewport's menu to preview it in your browser.

Once you're happy with the results, choose File > Export > Blend4Web (.html) to generate the standalone HTML file with all the 3D and interactivity data bundled into it.

Here's an example .blend (requires that the Blend4Web SDK be installed):

And here's an example HTML file generated from the .blend to demonstrate the functionality (requires that WebGL be enabled in your browser).


Flatten the base of STL file & cut it into a regular shape

Import model from stl format

In edit mode, select all vertices and delete duplicates (Merge distance in 2.80) with desired accuracy

Select all faces in edit mode and Extrude it down

Resize selected faces by Z axis to 0, align it by lowest vertice of top surface

Select all faces, again remove duplicate vertices and Recalculate Normals (if everything fine you do not need to make it Inside)

Add Cylinder object and make it right

In edit mode remove cylinder top face, select all leftover faces and Extrude region to cover the main object

Add Boolean modifier to Terrain and set up Difference with Cylinder

Profit!


RC 2.7 Blender/Volumetric Shading Cycles

Smoke rendering is still not quite possible in 2.7, simply because there is no way to put the smoke voxel data into a cycles shader.

This is a target for 2.71:

  For 2.71, the following features are planned to be worked on:

  Volume rendering: smoke / voxel textures, better sampling, camera in volume

However, it is possible to render volumes based on textures:


Is there a way to make Cycles render slower to use less GPU resources

70 degrees is not too hot and it's completely normal for a working GPU. Something beyond 85 degrees would start getting concerning. Anyways, you may set the tile size to a low value (16 x 16 for instance) to get what you want. Here you can see a table that shows how different Tile sizes can affect rendering time when using a GPU.

However, from a more environmental perspective ( :) ) I don't recommend you doing this since you will have to leave your computer on for a much longer time to get the final rendering. In the meanwhile, your computer is using way more electricity than it would if you use the GPU efficiently by setting the tile size to a higher number (e.g. 224 x 224). Normally, a mid-range GPU uses around 200 watt-hours or less working with the highest load. When idle, it uses around 30-50 watt-hours. The rest of the hardware for your computer also use at least around 70-100 watt-hours in idle and maybe around 200-300 watt-hours when they are under descent load. Assuming that you don't do anything else overnight (8 hours) and just leave your computer on for rendering your computer will be using something around 8 x 200 = 1600 watt-hours. The number 200 represents 100 watt-hours for your [almost] idle computer and 100 watt-hours for your GPU which is not under heavy load due to small tile size. However, if you set the tile size to a higher number and the rendering takes 2 hours your computer would use something around 2 x 300 = 600 watt-hours. 300=100(everything except GPU) + 200 (the GPU under heavy load).

Note that all of these numbers are just a rough approximation and could widely vary depending on your hardware but one thing that won't change is that leaving your computer on for longer will potentially use more watt-hours than finishing your rendering faster and turning your machine off :)


How do I split an edge with a key shortcut?

Select the vertex, face, or edge that you want to rip, and press V.  You then can move the separated vertice(s) around, or right-click (or possibly left-click, if you select with the right mouse button) so that they are on top of each other but not connected.


Is the blender smoke engine able to do this?

I don't see why not. I'm not seeing anything particularly fancy going on in that sim. It appears to just be a spinning block emitting smoke that rises into a sphere.


Can compositing be displayed in the viewport render?

No that can not be done. The compositer does not render in viewport. The viewport render is just a quick preview of the scene.


Where is my object "dimensions" control?

The dimensions of your object can be found in the properties panel. To bring up that panel either click on the little '+' icon at the top right of the 3d view or hit N with your mouse above the 3d view. The dimensions are located under the Transform heading.


Blender plane effect from blender render to cycles render

I think it's better not to give up to ready to use tools but just once learn how the transparency work in cycles, and then just use the knowledge.

https://www.youtube.com/results?search_query=transparent+textures+in+cycles

It's fairly easy. All you need is your png image's Alpha output as a mix node Factor to mix your image color in a Diffuse shader and a Transparent shader.


Blender 2.9 Not Displaying DDS textures in viewport

I'm having a similar issue with .DDS files on a project and apparently all you have to do is convert them to .png. Should be as simple as just renaming the suffix from .dds to .png (but make sure you do this with backup files!)
Can Blender open .DDS files?


How to export amodel from blender with textures and animations to use the model in Irrlicht?

According to the Irrlicht Feature page, the engine supports the follow for fomats and texture types.

Direct import of common mesh file formats: Maya (.obj), 3DStudio (.3ds), COLLADA (.dae), Blitz3D (.b3d), Milkshape (.ms3d), Quake 3 levels (.bsp), Quake2 models (.md2), Microsoft DirectX (.X)… [more]
Direct import of Textures: Windows Bitmap (.bmp), Portable Network Graphics (.png), Adobe Photoshop (.psd), JPEG File Interchange Format (.jpg), Truevision Targa (.tga), ZSoft Painbrush (.pcx)… [more]

In order to export the mesh, you need to select the various components, then from the File -> Export menu you have a variety of options to choose from. See image.

After you have it exported then its a case of doing the engine side stuff.


how to realign a bone when a lot of constraints are used

There is no automated function for fixing false constraints, because there is no way blender knowing whether this constraint is doing it's intended job right or wrong. You have to fix this manually.

The only automated feature, is "clear transform" (type it after pressing SPACE). but this only resets your animated translation, scale and rotation and will most likely don't fix your problem.

You actually have to manually click through every bone and disable and enable the constraints (by clicking on the eye icon of the constraint), to find the wrong constraint and fix it by hand.


Uninstall and reinstall blender I did that and it worked!


When I parent an object with a bone the object moves its place

You must have parented the object with a bone that is not in Rest pose, so first select your bone in Pose mode and altG, altR, altS to reset its location, rotation and scale.


How may I create a continuously looping animation?

To do this, you'll want to add a Cyclic F-modifier. Go into the Graph Editor and select the keyframes that you wish to loop over (over their respective time period), press Shift + E, and select "Make Cyclic (F-modifier)".


Blender is not known or marketed for its NURBS support, it is primarily a polygon modelling tool. While we have great modifiers like the Skin Modifier you mentioned, we don't have anything out of the box that would produce comparable NURBS surfaces.

A scripted solution also seems a bit beyond what is convenient to do in Blender, the API has limited support for generating arbitrary patch shapes that would be needed to do your Question justice.

I'd like to be proven wrong someday, or today, but for now I'd like to offer this as an interim answer and not just a cheeky comment. There are better tools for generating NURBS, consider freeCAD or any of the other free CAD/NURBS alternatives.


Edit: Note this is an ancient answer, pre-Filmic Blender. The TL; DR version is that you must always pixel manage everything. Do not turn transforms off, and appropriately tag your buffers.

  No matter how many times I try to read about color spaces, I always
  feel like I've walked into a movie 45 minutes late.

Don't feel too bad as there is so much misinformation out there and confusion that many artists end up following what amounts to digital alchemy rituals in order to get things right. The best advice I can give you is to figure out who you believe you can listen to, and ask as many questions as you can until the subject is absolutely clear. Your work will most certainly be elevated once you manage to grab onto the rather slippery subject.

  Since I'm looking at Blender with a computer screen which presumably
  already has a limited color space (compared to human vision) why would
  I want to push a button that at least appears to limit it even
  further?

This is a seemingly simple question that has a massive set of roots under the surface. The TL;DR is that if you don't enable sRGB, the result is wrong.

  I like the colors I see when sRGB is turned off, but should I be using
  it anyway?

TL; DR: Yes.

Since you took the time to ask the question, I'll do my best to try and give you an entry level conceptual framework to work with. Hopefully it will aid your understanding and help you grasp a little bit more about colour and its management.

Two Sides to Colour

At the core of colour and how it is encoded into data are two loose concepts.

The first is the colour of the light, or in colour nerd terms, chromaticity. When we think of an RGB triplet of data, we have to ask ourselves what the values mean. RGB data is merely an arbitrary numerical representation of three primary lights for each of the red, green, and blue channels. If I were to say "Hey, grab a flashlight in your house that looks red and turn the slider up to 0.8-ish.", that is roughly what we are communicating when we fail to use colour spaces and colour management; we are communicating absolutely nothing.

Without associating the RGB encoded values to a colour space, we are speaking gibberish. We know nothing about the actual colour of the light on your flashlight, nor do we know what the heck 0.8 means in any meaningful representation.

In addition to the chromaticities of the primary lights, we also have what is known as a transfer function, sometimes erroneously called "gamma." This is a term that describes how the values relate to each other in intensity, where the ground truth is a radiometrically linear quantity of light in relation to a scene or a display’s output. 0.8 in our example above tells us absolutely nothing about how intense the value is in relation to the other values because we don't really know anything about the encoding system used nor how the transfer function is defined.

Colour Space

To solve the above issues, we need more information than purely the relative RGB data. We need to communicate what the values actually mean in relation to some known standards or ratios. If we know what the colours of the primary RGB lights are in absolute terms, what the transfer function ratios are for the data, and some other aspects, we could call that combination of variables a colour space; an encapsulation of a bunch of additional data not communicated with the relative RGB encoded data.

sRGB is one such creature. sRGB has very clearly defined absolute chromaticities defined for each of the red, green, blue channels, as well as a defined white point. It also includes specifications for the transfer function. These facets allow us to 'decode' the RGB values in an image and properly communicate their intention and handling through a pipeline.

Why Linear?

So what does Blender have to do with all of this and why the hell do we see "linear" somewhere and what is sRGB and why? Why? WHY?

The answer to this is rather simple. In practical terms, Blender is completely blind to the colour of the lights (see chromaticity above) and merely worries about performing math on the data values. Cycles, however, is a ray tracer and attempts to, as best as it can with a tri-colour or tristumulus model, emulate real-world physics when it comes to rendering.

Real world physics is pretty simple when it comes to math. One unit of light plus one unit of light is, in shockingly, two units of light. Energies operate in a linear fashion, and as such, they behave very rationally.

sRGB on the other hand, for various historical reasons and circumstances, is a non-linear colour space. That is, the transfer function portion of the colour space is bent in such a way that the values are not linearly related. 0.4 plus 0.4 in sRGB is not twice the radiometric amount of light! To see a quick visual effect of this non-linear nasty math, fill up a background in your favorite imaging application of full green and full blue for a cyan colour. Now take a fuzzy fully red brush and paint across it. See the nasty fringing? That is a result of bad and broken math due to a nonlinear reference space.

When you load an image in Blender, it is rolled through OpenColorIO. OpenColorIO is the library that handles and tracks all of the colour space related complexities. The goal of OpenColorIO within Blender is to make sure that the reference mixing space is always linearized such that Cycles can perform proper math for the imaging.

Phew

So why sRGB? If we use a linearized reference space, and we were to dump those linear values direct to the display, our display's output would look wrong. In particular, it would look extremely dark because we haven't properly "corrected" the values back to a nonlinear response. When we select sRGB in Blender, we are telling the program to roll the linearized reference data back out through the correct nonlinear sRGB transfer curve.

If we don't do this, the data is entirely incorrect for storage in a JPEG, a TIFF, or other such nonlinear wrappers. It is also completely incorrect for viewing.

So when you are entering your values, you need to be certain whether you are entering tone response curved values or linearized values, and be absolutely careful at which point in the pipeline you are entering them. An image loaded from a JPEG would need to have its display referred non-linear data properly linearized to display linear before use.

If you mix and match the values without care, the visible representation of the values will not match what is 'expected' from other applications that are likely using nonlinear sRGB values.

This is, despite being a long winded bunch of rubbish, only the tip of the colour space iceberg. There's so much more to expose yourself to that will almost certainly be interesting to anyone creating visuals.

I hope I didn't lose you, and I hope you manage to understand why you should be using that odd sRGB viewing transform. I also hope you try to learn a little more about the rather vast subject of colour management.

Addendum

This answer was provided in the context of the default set of transformations present in Blender. The answer tackles "Should there be a transform between the scene referred data and the display referred output?" abstract question. To this end, the answer is provided in that context. If this is of interest, researching the various transforms that can be used to elevate scene referred rendering and imagery would be useful. There's more than a few of those out there now...


IK restraint makes hand rotate weird in relation to gun, how to fix?

You need to change the rig. Now you have almost no control over wrist rotation. Also it's never a good start to have rig rotation and location different then 0,0,0 and scale different then 1. It will in almost every case cause problems after exporting to a game engine, so you need to fix this. As for the rig, you need to make IK targets of the hands chains to be exact copies of hand_l and hand_r bones, parented to the root bone. Then give both hand bones Copy Rotation constraint set to World Space > World Space and Bone target of appropriate IK target bone. This will give you more control and make your work easier.Also use Child of constraint for IK targets to follow gun bones, when you set up the grip (don't forget to click on set inverse after that or you will be disappointed)  It's hard to repeat rigging steps just by reading it and .gif would be to large, so here is a link with your file, but with fixed rig. Compare and learn.Happy New Year :)


Lightsaber effect in cycles without compositing?

I'd say postprocessing, simple glow... but if you really wan't pure cycles:

1) Start with a cube and 3d spherical gradient texture with coordinates set to Object (Absorption shader with inverted colors are here for simple visualisation):

this gives us a smoothed sphere inside the cube:

2) Scale texture coordinates in Z by some really low value - this will stretch the sphere texture in that axis, giving us something similar to cylinder:

3) remove Invert Color and Volume Absorption shader nodes (which were used just to see what is really going on with the texture when scaling and using Object Texture coordinates) and plugin Mix shader node with Transparent and Emission shaders. Plug the output to Volume socket:

4) It still is centered stretched sphere, but the transparency interpolation is too linear - lets try different interpolation (by powering linear values):

5) Interpolation is much better, but the overall emission strength is way too low now - lets multiply the values now, and also stretch the cube in Z axis to desired shape:

Tweaking math nodes Power vs Multiply should give you expected smoothing and overall emission power.

6) Simply change emission color and lightsaber is ready to use:


Background reflected in glossy glass, but I didn't set it

Lookdev mode uses Eevee under the hood overrides certain lighting parameters for a faster, simpler preview. The idea is for it to provide a reasonably general lighting setup out of the box without needing configuration, enabling users to quickly develop how their materials look.

You may find the following questions also relevant:
Differece between Blender 2.8’s camera and world HDRI
How to use 2.8's default HDRi's in renders?


How do I bake my final Cycles render into a texture?

You'll need to load the map you want to save the baked image to in the node tree. It doesn't need to be connected.

Load up the blank image in the image editor then select what you want to bake to it.

Note that how the light responds will be calculated though the shader.


Hide parent object without hiding the instanced children?

Uncheck Display Instancer to hide the cube in the viewport and/or uncheck Render Instancer to hide the cube in the render.


The edges connecting my vertices are loopy rather that straight. Is it possible do straighten them + if so how can this be done?

In the modifier panel, disable "Adjust to cage" in order to modify the actual vertices position.


Is it possible to effect the spawning direction of a particle with a normal map?

I don't know a way to incorporate normal maps, you could achieve the effect you described by Subdividing W the plane several times. And deform it e.g. using Proportional Editing.

This way you would also be able to animate the geometry with Shape Keys


Why is inverting the selection selecting all vertices?

You might have double vertices. What might have happened is that the vertices that were selected were double ones, so inverting the selection also selected the vertices that were being overlapped by them. This would give the illusion that all vertices are selected.

To remove double vertices, in Edit Mode go to Mesh > Clean Up > Merge By Distance. Any detected double vertices will be removed and a message will show up saying how many double vertices were detected and removed. If no double vertices were removed. this might be a bug.


I have found the answer to my question my render for the 3D words was not a transparent in shading.


Groups not being converted to Collections

Background:

In Blender 2.80 both groups and layers have been merged into collections. Since they are technically two different things in Blender 2.79, it made sense to keep them still somehow apart or distinguishable from each other in Blender 2.80.

Layers are converted to collections, but groups are not going to be converted, since Blender 2.80 does not know, whether you want to create a collection for each group or if you want to use the groups from Blender 2.79 at all.

The latter is because Blender 2.7x's  group feature wasn't exactly intuitive to use and many people (including me) might have created random groups at one point without having any further use for them.

Enter Data Block IDs:

The three cubes in this screenshot of Blender 2.79 are in the same group named "cubes".

If you open the file in Blender 2.80, under "Properties - Object - Collection" you will find a new input/selection box named "Unique Data Block ID name", where you will find the name of your Blender 2.79 group.

If you click on the arrow to the right of the group name, a drop-down menu opens, where you can select "Select Objects in Collection". Now, all the objects that were assigned to the 2.79 group "cubes" will be selected. You can then assign them to a new collection by hand.


Circular distribution of objects getting weird

Vectors Matrices and Shared Mesh.

FWIW have added an approach that will be a lot quicker, use one operator call, and create only a single mesh
A single operator call, creates the cylinder at the scale and applies the 90 degree rotation about Y to its mesh.
This object is then passed to our create array method with a center, radius, how many to create, and optionally the collection to link them to.  This way can create Suzanne's or any object to "array".
As default it creates 40 about the point (1, 2, 0) with a radius of 1. To make same with question code would use 40 x 3 = 120 operator calls. See
Python performance with Blender operators
which can get horribly slow for a lot of copies.
The initial object is moved to the center point plus the radius in x.  A matrix is calculated that will rotate it an nth' of 360 degrees around z axis.
Matrix math to translate, rotate, scale with respect to a pivot point in Object mode
A copy is made, it shares the mesh of the original, and the alignment. The matrix is applied (multiplied) to its matrix world rotating it 360 / n degrees.  It is then copied and repeated until there is no more and we are back to first.
Duplicating a mesh object
import bpy
from mathutils import Matrix, Vector
from math import pi

context = bpy.context
scene = context.scene

def circular_array(
        ob,
        n,
        center,
        radius,
        revs=1,
        matrix=Matrix(),
        coll=bpy.context.scene.collection):

    center = Vector(center)

    ob.matrix_world.translation = center
    ob.matrix_world.translation.x += radius
    angle = 2 * pi / n
    name = ob.name
    ob.name = f"{name}_0"

    M = matrix @ (

        Matrix.Translation(center) @
        Matrix.Rotation(angle, 4, 'Z') @
        Matrix.Translation(-center)
        )
    for f in range(1, revs * n):
        ob = ob.copy()
        ob.name = f"{name}_{f}"
        ob.matrix_world = M @ ob.matrix_world
        coll.objects.link(ob)

# Test Call

# create our object to array
bpy.ops.mesh.primitive_cylinder_add(
        location=(0, 0, 0),
        scale=(0.1, 0.1, 1),
        rotation=(0, pi / 2, 0),
        )

ob = context.object
ob.name = "Tick"
# array ob 40 times about (1, 2, 0) with radius 2)

circular_array(
        ob,
        40,
        (1, 2, 0),
        1,
        )

Matrices
To further prattle on about matrices have put a matrix into the transform mix.
S = Matrix.Diagonal((1.01, 1, 1, 0.9))
R = Matrix.Rotation(28.6 * pi, 4, 'Y')

circular_array(
        ob,
        50,
        (1, 2, 0),
        1,
        matrix = R,
        revs = 10,
        )

Bringing a scale matrix into the equation would have a spriral effect.


Set parting option to 1:

Default zero parting used to interpolate children strands between nearest control strands, that smooth transition from one control strand to outers (if you render hair, not objects).


Blender 2.83: In edit mode, select both edges, then click mesh\clean up\merge by distance.  Keyboard shortcut is M > By Distance. In Blender 2.79, it was AltM.


How do I hide vertices not visible to the camera?

As per moonboots's comment, I had disabled Limit Selection to Visible, so I just needed to toggle this.


Best way to find the 2 closest vertices from a list of vertices?

Naively, this creates a look-up list of closest vertex indices.

import mathutils
import bpy

ob = bpy.context.object

# create a kd-tree from a mesh
me = ob.data
size = len(me.vertices)
kd = mathutils.kdtree.KDTree(size)
for i, v in enumerate(me.vertices):
    kd.insert(v.co, i)
kd.balance()

# create ordered list of closest vertex indices
closest_vIdx = []
for v in me.vertices:
    co_find = v.co
    closest_2 = kd.find_n(co_find,2)
    closest_vIdx.append(closest_2[1][1])

#Insert the index of the queried vertex here:
vIdx = 5707

print (f"vertex:{vIdx} closest vertex:{closest_vIdx[vIdx]}")

Bear in mind with this one:

The distances are in 3-space, not necessarily down edges.
Only the 'first' of any set of equidistant vertices is chosen

You wouldn't want to build the KDTree (or the closest list) more often than necessary - the best way of finding the closest vertex may depend on exactly if/when you want to modify the mesh, and would therefore have to rebuild the tree.


Problem to create background in language other than English in the settings

Default nodes are in same order

Since you are looking at the default nodes created when setting a world to use nodes, then the zeroth item is the output node, and the first the background node.

Simply reference them on creation, rather than using a key.

>>> nw = bpy.data.worlds.new("xxxx")
>>> nw.use_nodes = True
>>> nw.node_tree.nodes[:]
[bpy.data...nodes["World Output"], bpy.data...nodes["Background"]]

>>> output, bg = nw.node_tree.nodes
>>> output
bpy.data...nodes["World Output"]

>>> bg
bpy.data...nodes["Background"]

To translate

To find what blender translates from the english to the currently set locale,

>>> bpy.app.translations.locale
'es'

>>> nw.node_tree.nodes[:]
[bpy.data...nodes["Entorno"], bpy.data...nodes["Fondo"]]

>>> bpy.app.translations.pgettext("World Output")
'Entorno'

>>> bpy.app.translations.pgettext("Background")
'Fondo'


Importing multiple files in blender import plugin

0
It turns out there are several things you need to do to make this work, it's not yet covered in the documentation.
First of all, it helps to know what the base class 'ImportHelper' does when using it in an import script. On initialisation, the script calls 'context.window_manager.fileselect_add(self)' which adds several objects to your class. This string in the source code gave it away:

"The string properties 'filepath', 'filename', 'directory' and a
'files' " "collection are assigned when present in the operator"

The 'files' object is what we need but that's only present in if you also have the correct property present in your class, for example:
files: CollectionProperty(
            type=bpy.types.OperatorFileListElement,
            options={'HIDDEN', 'SKIP_SAVE'},
        )

then, if that is present, you can access this in your class's 'execute' method to iterate through all the files in your selection:
for meshfile in self.files:
            filepath = meshfile.name
            print(filepath)

Also, remember to include the correct properties, I include these in my importer:
from bpy.props import (
    BoolProperty,
    CollectionProperty,
    StringProperty,
)


TypeError: UILayout.prop() when trying to display custom settings in a menu

import bpy

class CUSTOM_MT_menu(bpy.types.Menu): # Menu name need 'UPPER_CASE_MT_mixed_case'
    bl_label = "Custom Menu"

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

        settings = context.scene.custom_settings

        layout.row().prop(settings, "my_settings", expand=True) # Layout.prop(data, 'prop') # show data.prop

class CustomSettings(bpy.types.PropertyGroup):
    my_settings = bpy.props.EnumProperty(
        name="My Settings",
        description="Custom Settings",
        items=[
            ('S1', "Setting One", "", 0),
            ('S2', "Setting Two", "", 1),
            ('S3', "Setting Three", "", 2),
        ],
        default='S1'
    )

def register():
    bpy.utils.register_class(CUSTOM_MT_menu)
    bpy.utils.register_class(CustomSettings) #  CustomSettings need register first
    bpy.types.Scene.custom_settings = bpy.props.PointerProperty(type=CustomSettings) #  not BlendData, need Specify a data type.

def unregister():
    del bpy.types.Scene.custom_settings
    bpy.utils.unregister_class(CustomSettings)
    bpy.utils.unregister_class(CUSTOM_MT_menu)

if __name__ == "__main__":
    register()

    bpy.ops.wm.call_menu(name="CUSTOM_MT_menu")

BlendData cause TypeError: UILayout.prop(): error with argument 1, "data" -  Function.data expected a AnyType type, not tuple


When import OBJ the edge becomes 'strong'

These light blue edges are marked sharp.

It means they will be sharp when you Shade Smooth the object and Auto Smooth the Normals

You can remove them by selecting them, pressing Right mouse button and selecting Clear Sharp


Animating a masked sphere with "star" particles

Appended Answer Here:

For understanding's sake, I am trying to recreate what you have done.

You basically had a sphere with random emitted "star-mesh objects".

That Sphere had key-framed rotation information within it.

Then you did something like the following:

Select your emission mesh (where the star particles are being emitted from).
Go to the Modifiers Tab within the Properties Panel.
Apply the Particle Modifier.

???

If this is correct, then what you would probably want to do is add an empty object at the center of the original sphere's rotation.

Select Your Empty.

Hold Shift and select your sphere.

Next: Ctrl + L >> Animation Data. This will copy the key-framed rotation.

Now you can apply the Particle Modifier, to make all of your stars individual objects.

Next Parent these to your Empty.


OK, this is going to be a long one...
When you first create the "weird" cut, add the vertices to a vertex group, CTRL-G is the shortcut. With the vertices selected hit V to "rip" the edges creating 2 separate bodies, best to have Auto Merge off, RIGHT CLICK to end to tool without moving the verts. Quick tip, no need to select a vertex first then CTRL-L to select linked, just hover your mouse over the vertex you want and hit L Once you have one of the bodies selected, move them to a new object P. The new object and the original with both have the same vertex group so you can select in Edit Mode making the edge loop selection a breeze!

I've put my object at a weird angle so the following makes more sense.
The next step, to make the same face on each part is the trick!
Back in Object Mode, hide one of the objects for now.
First, edit the visible object and select the edge loop as described above ;) then hit F, it will look terrible but we'll fix that in the next step.

With that terrible face selected place the 3D Cursor at it, SHIFT-S To Selected CTRL-I to invert selection and H to hide it. Now back to Object Mode.
Square your view up as best you can to that terrible face you just created, doesn't have to be perfect, just good enough. Add a plane, align to view, edit plane, scale it to be bigger than the face and subdivide it, the more you sub the better the face will end up. Select all and X Only Faces so you are left with a grid of edges.

Object mode again.
Move the plane so that it is not intersecting the object but is still bigger when viewed normal to it and your face. Making the Transform Orientation Normal will help here.

Now the cool part!
Select the plane SHIFT-7 or SHIFT-CTRL-7 to view normal to the plane with the plane in front of the object.
Select the plane FIRST then select the object, enter edit mode. Make sure you still have all but the terrible face still hidden in the object. From the menu select Mesh->Knife Project If done correctly, this will project the edges of the plane onto the object and slice up that terrible face, there will be plenty of N-Gons but as this is for 3D printing it wont matter.

Now the matter of making the same face on the other part... Easy! (I won't give you key strokes here... you get the point!)
Edit the object your just made the "cool" faces for, use the vertex group again to select the vertices we need, then from the menu choose Select->Select Loops->Select Loop Inner-Region (you may need to invert that selection then select the group again) Duplicate the faces, move them to a new object.
Back in Object Mode join the new faces object with your original object that we hid at the start. Edit it...

Now select the linked verts of those added faces.
Choose a vertex that "stands out/easy to find on both bodies", make sure that is the active vertex.

Now with Snap to -> VertexSnap with -> Active selected move the selected vertexes to the correct spot, select all, merge by distance...
The alignment features should be a simple matter using booleans.
You're done!!
You should now have 2 separated objects with exactly the same faces that are readily 3D printable.
(I REALLY hope this answered your question!!)


Test script to import the blender.svg file.
As pointed out here  the newly added curves are not selected after the import.  For convenience added an empty parent.

import bpy
context = bpy.context
scene = context.scene
bpy.ops.object.select_all(action='SELECT')
bpy.ops.import_curve.svg(filepath = bpy.app.binary_path.replace(".exe", "") + ".svg")
newcurves = [c for c in context.scene.objects if not c.select]
# deselect all
bpy.ops.object.select_all(action='DESELECT')
# create an empty make it the active  object
empty = bpy.data.objects.new("Holder", None) # use filename maybe
scene.objects.link(empty)
scene.objects.active = empty
empty.select = True
# loop thru the curve objects
for c in newcurves:
    print("Curve: %s", c.name)
    # make it selected
    c.select = True
    # make the parent the empty if not already set
    if not c.parent:
        c.parent = empty
    # change some curve details
    curve = c.data
    curve.dimensions = '2D'
    curve.extrude = 0.003
    # sane object names
    c.name = curve.name
    # location
    #c.location.x += 0.332

empty.scale *= 200

Test on svg

If you are going to move and rotate append a call to geometry to origin operator.

bpy.ops.object.origin_set(type='GEOMETRY_ORIGIN', center='BOUNDS')


Video Sequence Editor: Is it possible to specify default strip properties?

Don't know why this old question went up on Twitter, but if anyone comes by, there is an add-on by Snuq(not me) to handle all the needs when creating a slideshow. Get it here: https://github.com/snuq/SnuSlideshowGenerator/blob/master/Readme.md


How to apply the multiresolution modifier from sculpt mode?

You need to raise the Preview value to match the Sculpt, and apply the modifier in object mode.


How can I create feathered edges on a circle?

You can use a RGB Curve or a Color Ramp node to control the transition :


I want to turn a 3D mesh into a height map and then use the height map to create a new 3D mesh with no undercuts

If you use the 'Mist' feature:

then enable it in the camera settings:

then adjust the start and end point that it gives you to the start and end of the model, in the world settings:

And finally, in the compositing editor, connect the mist pass to the render pass, to give you a high definition 'depth' pass:

Hope this helped!


Why is my displacement map virtually completely grey?

You are trying to bake a Displacement Map, but looking in your file shows you have no displaced mesh. What you want to do is create a Height Map from existing geometry.
This is a solution if someone experiences the same problem but has a displaced mesh: Check if you have applied the Displace Modifier and set Level Viewport to 0 in the Multires Modifier before baking the displacement.


why does the subsurface modifier create such a harsh edge here

It looks like it's a problem of normals, select all and ShiftN to recalculate and it will fix it.


Plug your Image Texture into the grey Subsurface socket of the Principled BSDF. To decrease its effect you can use a ColorRamp or a Math (Multiply) node between the Image Texture and the Principled BSDF.