text:
Fine cutouts with a wide bevel
I'm trying to model the following plate in blender:

I tried bending a plane to form the general shape of the plate, and then adding solidify, boolean cutouts and then bevel them.
At this point, whatever I do goes sideways really fast - the bevels overshoot or don't appear at all, the cutouts don't end up round, etc.
Here is an example of a simple attempt - I start off with a plane and a cutout (I have to bevel the cutter so that I have the round corners properly:

I then add solidify and bevel:

The bevel doesn't show, because clamp overlap is on... When I turn it off it either messes up the geometry, and the widest I can get it and still have it look reasonable is this:

Adding subdivision before the boolean and/or bevel doesn't help much either:

Can someone direct me, or help me understand what I'm doing wrong? Is my entire approach to the process wrong? Am I using the modifiers in a wrong way?
Thanks in advance!

well, the easiest answer is: do all booleans and then fix your topology before you try to apply subdiv or bevel to it... if you cut into mesh like that you will create a lot of ngons, you will need to remove them

I think the tool that cut those holes has a slight taper, which is why the top part of the round hole has a bigger radius than the bottom (inside) part.  I might try tapering the cylinder to form the slope between the top and bottom and not using a bevel at all.

Possibly relevant: https://blender.stackexchange.com/questions/234450/two-components-with-identical-modifiers-yet-the-bevel-modifiers-have-different/234635#234635

An approach without Booleans is to model this plate from a subdivided plane and then add some modifiers. Lay the mesh over the reference image and remove the square faces where the holes should be:

Then either extrude (E, S) and scale a support loop:

-or- fill (F), inset (I) and remove the face. Later creates an edge with even width. On the outer edges of the plate you need to use Extrude:

For comparison, the left/bottom area has extruded/inset extra support loops, the right/top area has none and is a bit jagged:

The round holes can be created with the Mesh:LoopTools add-on that ships with Blender (screenshot 1). The edges can be smoothed with the Relax operation of the LoopTools.

Good suggestion, way cleaner this way.

Thank you so much for the clear explanation, and the explanatory images! Not all heroes wear capes :-)
The solution is indeed far better than the boolean approach, and the relax feature + insets solve it perfectly IMO. Cheers!


text:
Turning interactive geometry nodes into interactive web asset
I've been following some tutorials to make some cool stuff using Blender's geometry nodes. I really like this model that reacts to the proximity of an empty - here's the youtube tutorial for a visual understanding.
https://www.youtube.com/watch?v=bzsLYqkeoww&ab_channel=Vipraz
I'm wondering how I could turn this into an interactive web asset. So rather than an empty controlling where the extrusions occur, the users' cursor location on the web page is used. I could, of course, render out an image sequence of the empty moving across the sphere from left to right, and map this animation to the users' cursor location along the x axis of the page. But what if I want the interactivity to respond to the y axis too?

If you can bake the animation to a shape key sequence (see https://blenderartists.org/t/export-bezier-curve-animation-as-gltf-and-or-fbx/1151423/3) you should be able to export that to glTF. But the geometry nodes themselves do not export, so the animation does need to be baked.

@DonMcCurdy Hmm that poses some issues as I'd like it to be fully responsive to cursor location as it is within blender. Baking would restrict it to a specific path that I've set the empty along. Do you know of any way to essentially host Blender's viewport as a widget on a website? I know Blend4Web did this but it is only compatible with 2.79 and earlier.

I'm not aware of something like that unfortunately. This would probably need to be coded in a webgl library like three.js or babylon.js instead. Longer-term there are some efforts (see: MaterialX) to create standards for node graphs that can be used across different software.

I don't do much web programming and maybe this is too hacky, but you could render the scene with the empty at each position on [x,y], and make the web page keep swapping in the appropriate image given the cursor's x,y position?

Your best bet would be to handle the objects that emerge from the sphere in javascript with three.js so you'd need to:

generate N meshes as the shards that emerge from the sphere, and make sure the origin of each shard mesh is at it's base so that in three.js when we initialize the position as 0,0,0 would put the bottom of the shard at the center of the sphere.
randomize the rotation of the shards, it's easier to have empty objects as parents for each shard and that way you can randomize the rotation of the empty object having that affect the shard's rotation, and then simply increment each shard mesh's Z position to move them out towards the surface of the sphere.
at setup time (not during each update, since this value shouldn't change and it could be expensive to calculate them all) send a raycast from each shard up to the surface of the sphere and get the point where it intersects with the surface, and either push those points with their associated object's ID into an array for later or save them as .userData on each object depending on whether you want your update() function to iterate through three.js scene Objects or iterate through an array with an ID to reference the objects.
make a function that gets either touch or mouse position depending on what's available and send the normalized input to a callback as (x, y)
in the callback, send a raycast from that point on the camera going straight forward (relative to the camera) which should give you the point on the sphere where it intersects
then calculate for each projected point of where the shards would be on the surface if any of them fall within a fixed distance from the point on the sphere where the cursor intersects, and update each mesh's Z position and scale based on how far it is from the cursor position.

Note: it will be more performant to use something like an InstancedMesh for all the shards rather than individual meshes.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
report error , menu not found
I am getting Report error menu not found when I right click in edit mode to get the vertex content menu.
I deleted blender and reinstalled and I am having the same problem , would really appreciated any tip to solve this.
I am using Blender 2.91.2 on a Macbook pro 10.7.15 Catalina

Tks Duarte Farragota for editing my question :) and making it easier to understand , unfortunatly like all  previous ones I got  no answer:( I am totally new here , is there anything I should do to get a proper answer?

Ok guys solved it:)!  I just  loaded factory settings inside blender preference.
Click Edit choose  Preference
Press on hamburger menu at the bottom left and choose load factory preferences.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
How to create front wall for these walls?
I tried making a loop cut at the spot presented in the picture, then grabbing the bottom faces and extruding downwards and finally making the faces flat in the same height.
That leaves me with not so bad but really kinda weird result, like you know there is a better and proper way. I always had trouble figuring it out, sometimes i do it like i said, sometimes i create separate mesh with the shape intended.
What do you suggest?

No reply to the answers posted?

A simple way to create a wall with nice topology.

Select your vertices and go Vertex > New Face
Inset the wall a bit (might be useful later) and uncheck Boundary
Subdivide the bottom edge (Edge > Subdivide)
Connect the vertices to keep quad topology (Vertex > Connect Vertex Path)

Thanks for editing it. It is very helpful. I never knew I could do something like that.

If you know that you will use the same modifiers on all the pieces you can make them inside the same object but as separated meshes (not connected with the other mesh).
If you need to apply different modifiers you'll need to have different objects.


text:
Viewport objects became transparent gray
My viewport was working normally halfway through this project, but all the objects became a light transparent gray.

I now see very little definition, and can't really select faces. How do I turn this back to the standard?

Be sure to have the X-Ray disabled in the Viewport Shading popover.


text:
Adjust fall off custom curve of Vertex Weight Edit modifier using script
I'm writing a script to use with headless Blender but can't seem to figure out how to adjust the fall off curve of the Vertex Weight Edit modifier. Just want to move the upper point (1,1) down to something like (1,0.4). Picture for reference of desired outcome.

Thanks in advance for any help!

As a one-liner :
bpy.context.active_object.modifiers["VertexWeightEdit"].map_curve.curves[0].points[1].location = (1, 0.4)
Let's see how we cracked this using the Console inside Blender :
obj = bpy.context.active_object
obj
>>> bpy.data.objects['Cube']

We selected the active object. Let's get a reference to the modifier.
mod = obj.modifiers["VertexWeightEdit"]
mod
>>> bpy.data.objects['Cube'].modifiers["VertexWeightEdit"]

Now let's print its attributes so we can see where to dig around.
dir(mod)
>>> ['__doc__', '__module__', '__slots__', 'add_threshold', 'bl_rna', 'default_weight', 'falloff_type', 'invert_falloff', 'invert_mask_vertex_group', 'is_active', 'map_curve', 'mask_constant', 'mask_tex_map_bone', 'mask_tex_map_object', 'mask_tex_mapping', 'mask_tex_use_channel', 'mask_tex_uv_layer', 'mask_texture', 'mask_vertex_group', 'name', 'normalize', 'remove_threshold', 'rna_type', 'show_expanded', 'show_in_editmode', 'show_on_cage', 'show_render', 'show_viewport', 'type', 'use_add', 'use_apply_on_spline', 'use_remove', 'vertex_group']

We've got some interesting things here. We're interested in map_curve.
curve_map = mod.map_curve
curve_map
>>> bpy.data.objects['Cube']...CurveMapping

dir(curve_map)
>>> ['__doc__', '__module__', '__slots__', 'bl_rna', 'black_level', 'clip_max_x', 'clip_max_y', 'clip_min_x', 'clip_min_y', 'curves', 'evaluate', 'extend', 'initialize', 'reset_view', 'rna_type', 'tone', 'update', 'use_clip', 'white_level']

type(curve_map)
>>> <class 'bpy.types.CurveMapping'>

curves = curve_map.curves
curves
>>> bpy.data.objects['Cube']...curves

type(curves)
>>> <class 'bpy_prop_collection'>

A Curve mapping object holds curves. Here we only have one but some curve mapping objects have more (eg RGB curves node in the shader editor). We can access the only curve by accessing the first element.
curve = curves[0]
curve
>>> bpy.data.objects['Cube']...CurveMap

type(curve)
>>> <class 'bpy.types.CurveMap'>

dir(curve)
>>> ['__doc__', '__module__', '__slots__', 'bl_rna', 'points', 'rna_type']

A Curve Map object holds points.
points = curve.points
points
>>> bpy.data.objects['Cube']...points

type(points)
>>> <class 'bpy_prop_collection'>

The Points object is a collection holding reference to points.
p1 = points[1] # We access the second point, which is index 1 with 0-based indexing
>>> p1
bpy.data.objects['Cube']...CurveMapPoint

type(p1)
>>> <class 'bpy.types.CurveMapPoint'>

dir(p1)
>>> ['__doc__', '__module__', '__slots__', 'bl_rna', 'handle_type', 'location', 'rna_type', 'select']

A Point object holds the point location. location is supposed to be a float array, so we can use a tuple.
Note that you want to be tweaking p1.handle_type to change the interpolation type.
p1.location = (1, 0.4)

If you just want to modify the y value (second index of the array) :
p1.location[1] = 0.4
You'll notice when you run this and hover your cursor over the widget that the point moves, but not the actual curve. Digging in the docs shows an update method we can use.
curve_map.update()

If you're using this in a script and don't want to have to hover you cursor over the widget to force a UI redraw, you can tag all the areas to redraw on the next frame.
[a.tag_redraw() for a in bpy.context.screen.areas]

Demo code with some safety checks:
import bpy
from mathutils import Vector

obj = bpy.context.object
vertex_edit_modifier = None

# Get the modifier
for modifier in obj.modifiers:
    if modifier.type == 'VERTEX_WEIGHT_EDIT':
        if modifier.falloff_type == 'CURVE':
            vertex_edit_modifier = modifier

# If the modifier is present and its type is set to 'Custom Curve'
if vertex_edit_modifier:
    # Get the curve collection
    curve_map = vertex_edit_modifier.map_curve
    # Access the points of the curve (there is only one curve)
    for count, point in enumerate(curve_map.curves[0].points):
        # Compare the location
        if point.location == Vector((1.0, 1.0)):
            # Set the values
            point.location = Vector((1.0, 0.4))
            print("Point No {} set to custom location".format(count))
    # Update the Curve
    curve_map.update()

Very nice... 3 minutes to late, wrote a demo a demo script with a few checks: https://pasteall.org/cVfR What do you think about adding it to your answer?

@brockmann yeah no problem go ahead :)

@brockmann and Gorgious - wow this is such an educational answer. Very helpful and I now know how to go about solving similar problems on my own! Thank you!

y'all make a good teacher, Gorgious !


text:
Append Materials Using Python
Trying to append a material from one blend file to another but not having any luck. I've tried two methods so far.
Method 1:
bpy.ops.wm.append(
    filepath="material.blend",
    directory="/Users/me/Desktop/Materials/material.blend\\Material\\",
    filename="Material01")

In the console this returns {'FINISHED'} but there is no new material appended to my file.
Method 2:
# path to the blend
filepath = "/Users/me/Desktop/Materials/material.blend"

# name of object(s) to append or link
mat_name = "material01"

# append, set to true to keep the link to the original file
link = False

with bpy.data.libraries.load(filepath, link=link) as (data_from, data_to):
    data_to.materials = [name for name in data_from.materials if name.startswith(mat_name)]

#link object to current scene
for mat in data_to.materials:
    if mat is not None:
       bpy.context.collection.materials.link(mat)

I read that this method is more appropriate, but again, nothing happens. Method 2 was originally written for objects in the example I saw, so is there maybe something I'm missing for materials?
Interestingly, after running either of these, when I go to manually append (file>append) my file explorer opens on the material I'm trying to append. So it is getting Blender to look at the right material, but not appending it.
Any help greatly appreciated!
CK

Also see: https://blender.stackexchange.com/questions/9365/how-can-i-import-materials-from-another-blender-file-with-python/9366#9366, https://blender.stackexchange.com/questions/147488/load-and-change-material-with-python-script and https://blender.stackexchange.com/questions/23433/how-to-assign-a-new-material-to-an-object-in-the-scene-from-python

The below seems to work - it appends all materials from the .blend file. Not sure why the original code isn't working but for my purposes the below is fine as each file only contains one material anyway
with bpy.data.libraries.load(filepath, link=False) as (data_from, data_to):
    data_to.materials = data_from.materials

I guess the code in question is not working because of the if-statement. You are asking for a material, that startswith "material01" in its name which is most likely not present in the other blend file.


text:
Update Float Property Based on Selected Object
I'm writing an add-on and have a float property which drives the thickness attribute of a solidify modifier for the selected object. Currently, the float property displays the last value assigned by the user using that property. Instead, when the user selects an object, I'd like the float property to display the value for that object's solidify modifier.
I've written this function but from what I've read, this won't work anywhere within the draw or poll functions for the panel.
def SyncThickness():
    myprops = bpy.data.scenes["Scene"].my_properties
    if len(bpy.context.selected_objects) >=1:
        myprops.thickness_float = bpy.context.selected_objects[0].modifiers["Solidify"].thickness
    else:
        myprops.thickness_float = 0

Is there anyway to call this function whenever a different object is selected? Or is a different approach required?
Thanks
Chris

Use Application Handlers (bpy.app.handlers)
import bpy
from bpy.app.handlers import persistent

@persistent
def update_function(dummy):
    print("run...")
    # when select a object or depsgraph data changed, it will run

bpy.app.handlers.depsgraph_update_post.append(update_function)

API link: https://docs.blender.org/api/current/bpy.app.handlers.html?highlight=load_post#bpy.app.handlers.load_post

Works perfectly, thank you!

You could just utilize the modifier property directly:
import bpy

class VIEW3D_PT_test(bpy.types.Panel):
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_category = "Test Panel"
    bl_idname = "VIEW3D_PT_test_panel_1"
    bl_label = "Test Panel 1"

    def draw(self, context):
        layout = self.layout
        box = layout.box()
        col = box.column(align=True)
        col.label(text="Sub Panel label")

        obj =context.object
        if obj and obj.modifiers:
            sol_mods = [m for m in obj.modifiers if m.type =='SOLIDIFY']
        if not sol_mods:
            return
        for m in sol_mods:
            col.label(text=f"{m.name}")
            col.prop(m, "thickness")

classes = [VIEW3D_PT_test,
        ]

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

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

if __name__ == "__main__":
    register()

This would also probably work perfectly for my purposes - in fact I'm going to save this example as a template for implementing modifier properties in my add-on UIs.

Although the other method is fine, I think this one is more spot on and doesn't add any overhead. Using the modifier attributes directly also cuts on the code complexity. The depsgraph is updated when pretty much anything happens in Blender, so adding callbacks to this handler should be done with caution

May be this method has some limitations, because I noticed that if the N-panel is not selected to "Test Panel", the draw function does not run.

Not sure I understand the limitation as no non visible panels are drawn. the underlying property from the modifier is accessed in the same manner regardless. By not constantly forcing updates every couple milliseconds to every accessible property in a scene you improve performance.

@XY also due to the fact there was no error checking in the original post to verify an object has modifiers and specifically a solidify modifier using the app handler will cause background warnings/errors to constantly occur when a camera or light or any object without the solidify modifier is selected.


text:
How do I animate a face to change color over time?
How do I paint a face so that the color changes over a specific time frame?

by 'time frame', do you mean over the course of a part of an animation?  For 'color' are you talking about the face being all a single color and that color varying over time?

you can change colors over time like this:
Go to the frame where you want the color change to start.
e.g. frame 20

Now hover your cursor over the color and hit "I". This enters a keyframe for the color.

Choose now the keyframe where you want to end the color animation.
e.g. frame 120:

now choose another color, hover again the cursor over the new color and press "I" again.

result:

Thank you for the response.  I understand and am able to animate color change now.

Glad I could help. Please check the checkmark left of my answer if it helped you.


text:
How do I add keyframes to an object that I want to sculpt at time intervals?
Is it possible to have blender follow key frames based on sculpting differences of an object?  I have a glacier in Blender that I am trying to sculpt at time intervals on my timeline, but blender does not register that the sculpt of the glacier is different at time=0 vs time=10.

Key Mesh add-on can be used for this, but it is WIP. More info about the add-on: https://www.youtube.com/watch?v=jPvLQH17Y2Q&ab_channel=askNK

Can you please point me towards other resources that can be helpful to me?  Ideally I could virtually talk with someone who can help me create my desired animation.  Do you have any recommendations for how I can get help?

Could you not figure out a way to use shape keys? They work on the mesh deformation from scultping.


text:
unwanted discrepancy between solid viewport and rendered viewport
I have a Digital Elevation Model (DEM) that I imported into blender and overlaid ontop of google geodata using the Blender GIS add on.  The DEM layer (shown in white in the 3D viewport) looks correct in solid viewport shading:

But when I switch to rendered viewport shading, a black color shows up near the middle of the DEM where it is supposed to be transparent:

Does anyone know why the black color shows up in rendered view?  How do I emit the black color so that it is transparent instead of black?  Any help would be appreciated thank you.

The solution to my problem is to connect Alpha sockets from .tif to BSDF, then go into Material Properties tab under Settings > Blend mode > Alpha Clip.


text:
Render to float texture using Python API
Is there a way to render to a floating point texture format using blender's python api? Ideally I'd like to render to a RGBA32F. The suggested way to render to texture appears to be gpu.types.GPUOffscreen, but that doesn't allow specifying a format.
I've tried creating a gpu.types.GPUFrameBuffer and specifying a target texture as gpu.types.GPUTexture (which does allow a GL_FLOAT format), but there appears to be no way to get the underlying GLInt that would allow binding that target texture to use for further rendering.


text:
texture is on the wrong side of the mesh
I imported a obj and when it came in the texture is on the inside of the mesh. I tried to flip the normals but that didn't work i also tried to recalculate the normals but that didn't work as well. what should i do?                  https://www.dropbox.com/sh/6t4gcsslihmgb3z/AACxyD-4BZN_brBs1cIN0keGa?dl=0

Two similar geometries on top of each other: https://i.sstatic.net/u8VqP.jpg Split the object by loose part and remove the parts you don't like. Overlays > Face Orientation helps to distinguish them. Btw, the prefered way to share your blend here is using: https://blend-exchange.com/

Hello and welcome. While files, images, and external videos or links may be helpful additions they should not be the only way to obtain information about your issue. Don't make understanding your question rely on downloading a file, watching a video or visiting an external site. Use the builtin tools to upload images or gifs, along with thoroughly explaining the problem in written form so it can be indexed and searched for thus helping future visitors with similar issues.

Well I just figured it out, it took me some time to notice this mistake and I am not even sure how this thing was created.. but look at the top part of your UV:

Do you see something strange? Look closer to that black spot at the top:

If you take that small hidden UV and scale it over the old one:

For some reason you had 2 UV maps, 1 for inside and 1 for outside, your inside UV was right in a good place but your outside UV was scaled down
Edit: Aha! Your Mesh was duplicated, there were two meshes in one
Are you the one who made this? Or where is this from?

no i got it from sketchfab but thanks for figuring this out i was so confused

You should send message to creator about it, maybe it is some mistake he doesn't know about

yeah will do and thanks again

As mentioned in my comment, the geometries are similar and not identical, otherwise you could use Merge by Distance which fails in this case. I initially thought it is LOD geo, but obviously it's not, slightly rotated for whatever reason.


text:
Limit transparency to single layer for multiple objects
I'm trying to make a group of foreground objects transparent as a single entity, where they occlude each other like solid objects and then have transparency applied after, instead of each individual one having its own transparency.
There is an option in the material settings called Show Backface, but that only works for single objects. Is there a way to apply this effect for a group of objects? Merging shouldn't be an option as the foreground may also contain rigged characters and such. The objects in the screenshots below are only to demonstrate what I mean.
I also thought about compositing the foreground and background together as separate layers, but then I run into a problem of the background not containing shadows of the foreground (and vice versa), or if I render foreground + background as one layer and only background as second layer, then the shadows occluded by the foreground will start fading out too. Another thing I thought about was duplicating the whole foreground and giving everything a fully transparent material to render the background with shadows, but I'd rather avoid duplicating anything.
Is something like this possible? Compositor solutions are also welcome.
Transparency of each individual objects, not what I want.

Transparency of a group as a whole, I want this.

I'm afraid it does come down to duplicating your objects, because you need one set of them being transparent and casting shadows, and another set to actually render. Been trying some setups, and that's the best I could do, too. Also, just curios why the top result is undesired? It looks more realistic to be honest.

It's for a scene where a character is very close to a camera and you still need to see what's behind him. The problem is, my characters are modular, being composed of various parts like body, face, hair, clothing and accessories, like in a game with deep character customization, and it just looks wrong seeing every object being transparent individually.

I see. I think the best you can do with eevee is after you deem your scene ready for rendering, duplicate your character's objects, and have one view layer where they're invisible to the camera so they're still casting shadows, and another layer where the background is disabled and your character is opaque, and comp them together.

Found another solution by random using geometry nodes, which doesn't require setting up any extra view layers or doing anything in the compositor.
Individual Object Method

Add geometry nodes to one of the objects (or you can create a
new empty one just for this purpose)
Link in all other objects using Object Info node (also switch to Relative so they keep their position)
Merge them together using the Join Geometry node
Hide the actual objects, that you merged, from the scene
Don't forget to turn off Show Backface in material settings for your materials

Collection Method

Put all of your objects into a collection
Create a new object outside the collection with geometry nodes
Link the collection objects using Collection Info node
Run it through Realize Instances node
Disable the collection from view layer
Don't forget to turn off Show Backface in material settings for your materials

Result

Compositing Eevee

enable Shadow pass
change Cubes material setup of Alpha mode to Blend.
create View Layer for

Foreground objects
Background object
and one for all objects to composit Shadow pass

The trick here is Alpha Blend mode in material. Objects with Alpha Blend are not visible for Shadow pass ... technically Im not advanced in this area to explane WHY ... I dont even know if it is bug, missing feature or intended ... it just works like that. So if someone has an explanation for it - please dont hasitate to edit my answer (or create a new one).

It is still a mistery how this result can be helpful, but I guess that is what you asked for :)

Compositing Cycles
Under Outliner > Filter enable Holdout and Indirect Only
and use them in a way as shown on screenshots for each View Layer ...

Does this work with eevee though? I tried it and the Indirect Only features seems to not work with it. OP tagged eevee that's why I'm asking.

Yep, I thought about this, but sadly it doesn't work in Eeevee. Hopefully they'll make it work at least for shadows one day, like they did with holdout.

@Jack check the edit ... it should cover your Q now.

Wow, that's a very nice trick. Thanks! Anyway, you can read what it's intended for in a comment to the OP.

Material-only Eevee solution:

Only a single layer of refracting ojects will be rendered by Eevee, so use refraction (1.0 IOR, 0.0 roughness) instead of transparency and enable screen space refraction.  Full shadows, single layer transparency without compositing or geo nodes.

Very nice and simple solution! Though that also means I need to enable screen space reflections right? I'm doing NPR and I use glossy shaders to create speculars from lamps and I'd rather avoid other objects reflecting on those.

Yeah, I guess you'd need that-- but if you don't want to use it for anything else, you might be able to get away with reducing the max roughness on the screen space reflections.

That's a good tip, I usually use something higher than 0 and then sharpen it with ramps. Thanks.


text:
Geometry nodes: set position on global axis instead of local axis
How can I offset points using the Set Position node on global/world coordinates, so that they always move the same no matter the object rotation? I tried searching around and only found that you can do it with an external object using the Object Info node, but I don't really understand how to apply that with the Set Position node.
Here's an example of what I want to achieve. I rotated each curve manually inside their own modified node tree copies, but I'd prefer if I could just rotate the object directly for this effect.

All you have to do is to make the reference to an object positioned at the world coordinates, and then you can use the rotation to this object as the rotation base value for the Vector Rotate node.

That works, thanks! Though I'll have to ask, the linked object in the Object Info node is the same one that owns this node tree? From the screenshot it looks like so, but that doesn't seem to be working for me.

The object referenced in "Object Info" is just a cube, placed at world origin and with no rotation, and the nodetree is applied to the curves.

Sorry, It just looks a little confusing because I only used cubes in the scene ;-)

That's alright. I got a bit confused by the node editor breadcrumbs referring to the same cube as the one in Object Info.


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Random wave texture width, but with a normalized amplitude
I've been trying to make a procedural triangle or saw wave texture, where every gradient segment has a random width, but each starts at a value of 0 and linearly raises to 1 (and in the case of a triangle, goes back to 0), but I can't figure it out, is it even possible? Saw wave is probably better as that can be easily converted to a triangle wave using pingpong math node.
The closest I've been able to get is to use a single axis voronoi texture with random set to max, but that also randomizes the peaks. If only there was a way I could create single value columns for each wave that has a value of its respective peak, then I could easily normalize them.
Here are two different views of the same thing, top and side. What I want to achieve is that each of the spikes in the right view reaches the top of the plane.


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Shading where all normals point towards each light source automatically
I don't really know how to describe this better, but I've seen someone use this for their NPR shader and it looks like that method stopped working in 2.93, see this post: https://twitter.com/Moeark/status/1386968029083291648
Basically this shading looks like all normals are pointing to a light source without having to specify which object to point to, and on a material level, so you could blend this shading with diffuse for example. You can kind of replicate this effect with Normal Edit Modifier, but that affects normals for everything and only works for one target.

You can also see how it worked in a video made by the same person: https://www.youtube.com/watch?v=CAtNoegUYJM
Any ideas on how to replicate this?


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Raycast Node: Use target normals as rays instead of source normals (replicate Shrinkwrap Target Normal Project mode)
I'm trying to figure out how to use normals of a target as Ray Direction in the Raycast node instead of the source's normals, so that my source wraps around the target as if I was using a Shrinkwrap modifier set to Target Normal Project.
Here's my setup:

I tried adding a Capture Attribute node between the Subdivision Surface and Raycast nodes set to vector with the Normal node plugged in and using that for Ray Direction, but that doesn't seem to do anything.
I also tried the same, but with the Transfer Attribute node, which kinda works, but the result is all jaggy because of the interpolation.
I thought about using the Raycast node in reverse, but I can't figure it out.
Here's an animation of two overlapping objects, one with the geometry nodes setup (yellow) and the other using shrikwrap (orange) wrapping around an not-selected wall. I want the yellow object to behave the same way as the orange one.

And here's how the Shrinkwrap modifier looks:

The problem is that the raycast goes from individual points along the source geometry in the ray direction looking for the target geometry. Since everything is from the source's perspective, the source position and ray direction inputs to the Raycast node are evaluated in the context of the source, not the destination. Your use of normal * -1.0 is the right idea, but the wrong normal. It's the normal of the source point.
What you need is some way to go from a source point to a target normal. This is always going to be an approximation. One way is to just look at the nearest point on the target mesh. In this graph, remember that the unconnected sample position on the left is implicitly the position of the source geometry:

If you had a really detailed mesh that might not be correct and you might need to iterate or otherwise improve the approximation.
You can also extend this idea if you're doing some kind of "shrink wrap" by offsetting the source position a tiny bit so that you always cast from the outside even if the source geometry is sometimes slightly inside the mesh:

I guess you probably found the solution now, but if you use the Sample Index Node set to Vector and Face and connected to the Normal Attribute it will work between the Subdivision Surface Node and the Raycast Node.


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How do I widen a knife cut?
I'm trying to make a lazy river in a flat plane, and the first step I can think of is to thicken a line so I can extrude it downwards. I've tried using bevel on the line to thicken it, but the line ends up being of uneven width. Is there a trick I can use or a different approach to get an even-width channel?

if you bevel one of your edge it should keep the same thickness all along, are your sure that the scale is applied?

What do you mean by scale?

in Object mode, check the scale of your object in the N panel, if it's not 1/1/1 press Ctrl A (Apply) > Scale, and bevel again

I think I've figured it out, ironically. I worked on it for hours before this, but I just realized there's a "Width Type" parameter on the bevel, and when set to "Width" it keeps the width of the line even like I wanted.
Thanks everyone for the pointers!

add a plane, subdivide it a lot,
add a beziercurve (your river), give it a bevel, then convert it to mesh, give it a subdivision modifier
then add these modifiers to your plane and you get:

Thanks a bunch for replying! It's my bad, I should've specified - I want to keep the mesh low-poly. I'll definitely look into curves more now, though!


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How to do the lighting Of this character as shown in the image
I have been trying to figure out for the pass two days how to use the lighting to achieve the character as shown in the image below,
I tried changing textures, roughness etc but still failed everytime, please help and i want to render in eevee not cycles.
This is my work

so it looks like you're close to what you show, no? Maybe use a bit of Subsurface, or a bit of Emission? Also lower down the Specular value in the Principled BSDF?

Actually, there is just a minute difference, my character is a bit on the brighter side and the colors look pale even after using the same model, and my edges are too sharp as compared to the image


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Extending an animation
I have a mocap animation of a person jumping from a height of about 8 feet to ground level.
How do I make it appear that he/she is jumping from a height of 20 feet?

you probably need to go into the Graph Editor and change the location of the root bone on the Z axis

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.

The jump I have in mocap last 2 seconds. I would like it to last 4 seconds but not in slow motion if I stretched it out. I want the jump to look like he jumped from a height of 20 feet rather than eight feet.

This short tutorial is probably what you're looking for.

Thanks, Marty. I just started with Blender and found the short tutorial very helpful.

You're welcome.  CG Cookie can be a good source for short YouTube tutorials.


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Union between ranges in scripting
Using random I am trying to get a random value from within two different ranges, say between 1 and 3 or 4 and 5. But random only seems to accept a single range. Any help would be appreciated.

I'm unclear about the parameters of your question. What proportion of the values would be between 1 and 3 versus 4 and 5? You could create a parametric equation with a jump discontinuity, but this problem sounds more like a stats or programming problem rather than Blender/graphics. What problem are you trying to solve with this question?

The Python random.uniform() function returns a randomly uniform number between 0 and 1. We can, if needed, map that number onto another distribution with another range by using the Cumulative Density Function (CDF) of the other distribution. Here you have asked for a function with a CDF in the range of [1-3] and [4-5]. For simplicity, I'm going to assume a uniform distribution:

In the plot above, the x values are from random.uniform() and the y values are from the cdf function below.
def cdf(t):
    if t < 0 or t > 1:
        raise ValueError("t must be [0, 1]")
    if t < 2/3.0:
        return ( 1 + t * 3.0 )
    else:
        return ( 3 + t * 3.2/2.0)

The code snippet below was used to generate the plot using the cdf function.
from matplotlib import pyplot as plt
from numpy import linspace

x = list(linspace(0, 1,  50))
y = [cdf(t) for t in x]

plt.plot(x, y)
plt.show()

At the cost of an additional call to random.uniform for each random number you want, here is a python script that will produce random numbers from an arbitrary list of intervals, either with an equal chance of the number coming from each interval, or with the choice of range weighted by the length of each interval, or with the choice of range weighted by an arbitrary list of weights
To reduce overhead, if you want weighted ranges, you should call prepare_cumulative_weights or assign_cumulative_weights once before any calls to weighted choice
This can be changed to only use one call to random.uniform for each random number, but the math is somewhat opaque, so I offer you the simpler but less efficient version.
import random
from math import trunc

def unweighted_choice(intervals):
    """ Given a list of N tuples containing (start, end) intervals
        return a random number from one of the intervals.
        Each interval has a 1 in N chance of being used
    """
    n = trunc(random.uniform(0,len(intervals)))
    s = intervals[n]
    return random.uniform(s[0], s[1])

def prepare_cumulative_weights(intervals):
    """ Given a list of N tuples containing (start, end) intervals
        returns a list that uses the interval length of each tuple
        to assign it a cumulative position in a range that extends from 0 to
        the sum of all of the interval lengths.  This effectively assigns a
        weight to the tuple equivalent to the length of its interval.
    """
    weights = []
    t = 0.0
    for (s, e) in intervals:
        r = abs(s - e)
        t += r
        weights.append(t)
    return weights

def assign_cumulative_weights(raw_weights):
    """ Given a list of raw weights return a list of cumulative raw weights
    """
    weights = []
    t = 0.0
    for r in raw_weights:
        t += r
        weights.append(t)
    return weights

def weighted_choice(intervals, cumulative_weights):
    """ Given a list of N tuples containing (start, end) intervals
        and a list of cumulative weights, assigned from a monotic sequence
        returns a random number.  Each tuple has a chance of
        being selected from that is proportional to its weight.
    """
    f = random.uniform(0, cumulative_weights[-1])
    for n in range(0, len(cumulative_weights)):
        if cumulative_weights[n] > f:
            interval = intervals[n]
            return random.uniform(interval[0], interval[1])
    return -1

if __name__ == '__main__':
    intervals = [(1, 3), (4, 5), (7, 11)]
    raw = [7, 1, 1]
    u = unweighted_choice(intervals)
    print(f'An unweighted choice {u}')
    cumulative_intervals = prepare_weights(intervals)
    for i in range(1,3):
        w = weighted_choice(intervals, cumulative_intervals)
        print(f'Length Weighted choice {i} {w}')
    cumulative_raw = assign_cumulative_weights(raw)
    for i in range(1,3):
        w = weighted_choice(intervals, cumulative_raw)
        print(f'Raw Weighted choice {i} {w}')
```


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Bridge Edge Loops is going to opposite side of body along with dark mesh
I am trying to use the bridge edge loop to connect the torso and hips of a human model, but it creates triangles and looks like a mess. There are an even amount of points to connect. The hips have a dark mesh and white artifact/scuff marks on it in Edit Mode, which I assume to be the problem. I have tried most answers I could find on this site (recalculating normals, adding more vertices, merged vertices by distance, etc.) to no avail. Any help would be appreciated.
Bridge Edge Loop Mess

Dark Mesh

Here is the file to the project:

You have a mirror modifier on the chest and hip section, but unlike the chest where you modeled only half (as is normal when using mirror), you "completed" the hip section - you can see the left side is still there despite the mirror being turned off (this is also why you were getting the patchy z-fighting pattern with the mirror on, as it was causing overlapping faces).

To fix it, delete the highlighted section, turn the mirror back on, and bridge edge loops will work as normal.

Thank you. I was stuck on this for hours.


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How to disable visibility properties in animation (in viewport and render) for animated objects?
As an example : we have a collection of 30 cubes animated, some in scale, some in position/rotation or both.
I would like to see them all disappear at a certain frame.

I cannot join them (because of individual transformation keyframed).
I cannot link the animation datas (because they are different except for visibility).
Ultimately I thought I found a solution with geometry nodes with a Collection Info node that "clone" in one mesh the content of my cubes collection and so I can keyframe his visibility in the outliner. I have to exclude frome view layer the original cubes collection.
But I am curious to know if there was a solution before the geonodes advent.

Thank you very much.

put them all in the same collection.  You can then animate the visibility properties of the collection as a whole.

@Marty Fouts Are you sure? How? You can keyframe a collection instance visibility though

@moonboots.  Oops.  I must have used an add-on that allows that.  You're right.  In 3.1, at least, you can't keyframe those.

From Marty and moonboots comments, there appears to be a lacking in capability.  I also tried using "Instance to Scene" (selecting the collection in the outliner and right-menu) and still couldn't find a way to animate render.    I would use a trick: add a Build modifier to a new object, select Reverse and set the Start Frame one prior to "disappearance", set Frame Count to '1'.  Select all other objects, then the new modified object last and use Object >> Link/Transfer >> Copy Modifiers.  This should then add the one modifier to all others.  Delete the new unneeded object.

Before taking this advise, as an info I'm using Blender 2.92. First, select the object you want to apply this effect with. Then in Object Properties, scroll down to Visibility tab,and in there there's this 'Renders' check box. It has an Animate Property next to it. You can then animate this property as you wish. For example , if you want the objects to show up from frame 0 to 24, then disappear at frame 25, then do the following: 1) go to frame 0, check the box and click on the animate property, 2) go to frame 24, and re-click on the animate property, 3) go to the next frame, frame 25, and uncheck the box, then click on the animate property.
However, with this way, you need to do it one object at the time, because there's no Object Properties on Collections.


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Adding texture to Cast Shadows in Blender 2.8/2.9 Eevee
I have been researching if there is a way to add textures to cast shadows in Eevee. I found what I was looking for on Youtube but it only works in Cycles.
Here is the Video
https://www.youtube.com/watch?v=AA88laLTEIo
Is there a way to control the textures on a Cast Shadow?

The 'shadow ray' is not properly implemented in eevee. There is no alternative for it.


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Rendering just Grease Pencil masked out by other Mesh Objects
I am using Cycles in the latest Blender stable release.
I need to understand if there is a way to just render the Grease Pencil objects without the 3d mesh objects, but the Grease pencil objects would need to be masked out by 3d mesh objects.
The underlying issue.
I am trying to use Render Farms to render some of the bigger Blend files that are composed of 3d objects + Grease Pencil objects. Most of the Render Farms seems are not able to render Grease Pencil objects and the ones that can are out of my price range.
So I am wondering if it is possible for me to render the Grease Pencil objects on my own local machine (as it does not seem to be CPU intensive) then composite them together with the Render Farm's output.
Some things to note, the grease pencil output would need to be a transparent background so I can overlay it over the 3d output when compositing.
I am fairly new to blender and have been googling Combined and Z Passes for a way to achieve this. Maybe I am not using the right combination of keywords, hoping someone can point me the right direction.
Thanks

As I understand, you are using Cycles.

Don't forget to enable transparency (RGBA in output also):

Disable overlays and switch to viewport shading mode:

Then render using View → Viewport Render Animation

Unfortunately, standard render does not work here due to this bug


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How to replicate a dripping material or mesh?
Posting this again. Previously the asset was not viewable as it was a link to an Instagram post. Please view the link in the file I have uploaded the video.
I am trying to see how to replicate this material in blender from this artist. Please see Video here. https://arifqz.github.io/files/127264400_368795457682043_378612915796313300_n.mp4
Credit goes to the artist here. http://www.alexkiesling.com/animation-1
I am fairly certain they did this in Cinema 4d
Can it be done procedurally? or a particle system?
Thanks. i did a few searches and wasn't able to find the look I was going for

Hello and welcome. While files, images, and external videos or links may be helpful additions they should not be the only way to obtain information about your issue. Don't make understanding your question rely on downloading a file, watching a video or visiting an external site. Use the builtin tools to upload images or gifs, along with thoroughly explaining the problem in written form so it can be indexed and searched for thus helping future visitors with similar issues.

Please don't post the same question more than once. If your previous question was put on hold, address raised the issues by editing it so it can be reopened rather than post a new one, otherwise see What should I do if no one answers my question?

hey @DuarteFarrajotaRamos Apologies I will do better on posting future questions. I was just following the instructions from the previous post when a question has been closed.

It's not exactly the same, but try something like this - it just takes a Voronoi texture as a displacement and pulls it "down" on the Z-Axis. Enter #frame in the value node to make the value match the current frame (makes it move when you "play the scene).

Remember you need to be in cycles and have a heavily subdivided object for the displacement to work. You also need to enable "displacement only" or "displacement and bump" under the materials settings.
Looks like this - it actually looks much better/smoother, I just had to go low-res for a .gif small enough to upload - this is only a 3 second repeating clip:

Also, I just noticed, you can probably make it match your sample a bit closer if you choose Smooth F1 on the Voronoi texture.

Hey thanks for the tip. I am trying to set it up with the node configuration. I have #frame in the value node and have copied the node set up but for some reason its not behaving like the gif you posted.
Here is a link to the blend file on google drive.  https://drive.google.com/file/d/1_ja7CTi02pZAsfl2BEMc1Vba5qZhzhyA/view?usp=sharing

Your Map Range node has the input range mapped to a space between 1 and 1 (no space at all). Change the To Min to something like .6. HOWEVER - your mesh seems oddly subdivided. For the best results, start with a cube, add a subdivision surface modifier (catmull clark level 3) and apply it. Then add a Cast modifier set to sphere (default) and change the  Factor to 1. Apply that as well. Then, add another subdivision surface modifier (level 3 or 4), but don't apply it. This should give you a sufficiently subdivided "quad-sphere" (no tri's or poles) - optimal for displacement.

Also, you probably want to reduce the multiplication of the frame speed to something like 0.02.


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how to get a Noisy edge in Blender 2.8/2.9 Cycles or Eevee
I am trying to recreate a few animations using 3d. There is a certain technique in After Effects which I love which is to give your 2d vector shapes a kind of a noisy edge so it isn't so clean.
See Video here for example: https://i.sstatic.net/dnW69.jpg
obviously I can keep doing this in AfterEffects but I am trying to learn the extent of what is possible in blender.
Is there a way to add such a noisy edge to 3d Shape? Either compositing? Directly on the mesh (i assume this may take longer to process? or something in between?
Thank you

In Cycles you can change the material settings > displacement to something else than Bump to actually change the geometry:

Then you can pass something like noise to the displacement:

Not only Cycles requirement is possibly very expensive, but sometimes you also need to subdivide your geometry for more resolution of the displacement (on the right):

You can see the inside is changed as well, though it's unclear if it's a problem in your case, as the example you provided has a single color - you could say it's shadeless:

Other than that, you could use Freestyle to draw a line and then use a separate freestyle pass to remove alpha from the render around its edges (keep in mind it will not interact with the shading of the object, e.g. messing up Fresnel highlights), or You could use Normal (Fresnel/Layer Weight) to control alpha of the material...

Also, geometry nodes...
Of course you can animate the noise texture and therefore the effect.

Thanks for answering. You are right I don't need the centers objects to be noisy but mostly where different Materials meet. For example Material A has a border with Material B on the same Mesh Object, I would expect both Materials to have a noisy edge.
I am going to review all the methods you outlined and try to figure out the best fit. let you know. Thanks again.


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Trying to replicate Matrix Object from C4D in Blender
I am trying to figure out if there is a way to replicate this?
Basically being apply split a Mesh Object into an array of cubes or spheres.
The video here is a visual representation of what I am trying to do.
https://www.youtube.com/watch?v=VfGGdaiS1Bo

Have you tried geometry nodes?

For objects without volume, moonboot's direct method would be simpler than this one, (and as far as I can see, in C4D, you don't need  the Matrix Object for the effect shown in the tutorial).
From my understanding of the C4D docs, its Matrix Object is a non-renderable grid of points, which is first-class geometry; available to deformers, etc.
Other objects may be instanced on the points. The grid can be deformed, without deforming the instances.
In Blender, the volume of any object can be converted to a grid of vertices with this little GN group:

(I've tried with a particle system, too,but  there are a lot more settings, and it doesn't play as well with modifiers below it in the stack)
After that, you could set the grid's 'Instancing' to 'Vertex' in its Properties>Object tab, and parent an instanced object to it.
Or, for options of finer control, after any deformation or other effects, you could convert the vertices to instances, using another little GN group:

The result functionally emulates the C4D Matrix Object, as far as I can see:

The advanced solution would be to use GeoNodes, the classic solution would be to create a mesh that has the shape you need, open the Object panel > Instancing, click on Faces or Vertices, you'll disable the Show Instancing options later:

Parent the object that is supposed to be instanced to this first object with a CtrlP:

Result:


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Creating a Tentacle Ball in Blender 2.8/2.9
I saw this video on creating this Tentacle Ball in Houdini. https://vimeo.com/248824842
I am wondering what would be the most efficient way to create this in Blender. I am fairly new but trying to understand how to approach such a task. I have googlged for similar things in Blender on youtube but it didn't yield any good matches
I was thinking a few ideas, not attached to any.

Modeling the Tentacle Ball from scratch then attaching Rigid body physics to it.

or

Using Hair Particles with Ball

Again. I am not attached to any one idea, just looking for an efficient way to achieve this.  Since most of the time, I pursue and research a method only to find a better and more efficient way to do it.

Here is an approach with the Hair Particle System:

I made it mainly because I wondered if you can render the animation in Eevee and how long it will take to render a short animation. The problem is that the emission requires a baked light probe and it's static, not dynamic.
The modelling is quite simple:

create a sphere. Remember its face count (as shown stastic text overlay and status bar). It's 386 in this example.
apply the Scale to the object with Ctrl+A in Object mode if you have scaled it. The settings in this example are for default cube size (not scaled).

Enough modeled. Now the hair settings:

add a Hair Particle System to the sphere object
adjust the Emission settings:

Emission > Number set this to the face count of your sphere object
... > Hair Length and ... > Segments as you desire. Less segments makes the tentacles stiffer, more makes it more tentacle-ish. Try 1 m to 4 m and 5 to 10 segments.
set ... > Source > Emit From to Faces (default) and ... > ... > Particles/Face to 1

enable [X] Hair Dynamics. The ... > Structure > Stiffness value here also can be used to make the hair stiffer.
Cache: if you have more than one ball give the cache a unique name. Double-click or Ctrl+click the first nameless entry in the list
Render > Path > Steps: increase the number to 4 or 5
Viewport Display > Strand Steps: use the same number as for the Render above
Children: None if you want to have fat tentacles like the little ball on the screenshots -or- Simple if you like hairy ones like the big ball on the screenshots.
if you want hairy tentacles and used Simple then

try 20 for Children > Display Amount and ... > Render Amount and
a ... > Radius of 0.3 m (depends on the size of your sphere)
increase the the ... > Clumping > Clump value to something near 1 like 0.950
use ... > Clumping > Twist if you like (0.557, screenshot #3)
experiment with the Children > Roughness settings if you like the hair strands rough and a bit messed up

the Hair Shape section is important

set ... > Strand Shape to a negative value like -0.5 to have a thicker strand. It affects the thickness along the root to the tip.
set ... > Diamenter Scale to 0.3 for fat tentacles (no children) or `0.05' for hairy ones

last but not least, you can play around with the Gravity. Decrease it if the tentacles bend downwards to much (kinda like stiffness).

Render Settings

set Eevee > Hair > Hair Shape Type to Strip. This way you see in the viewport what you get when you use Cycles.
for fat tentacles set Cycles > Hair > Shape to 3D Curves

The shader is simple. It's the Hair Info node and a Color Ramp node. With two Math nodes you can rotate the color ramp for a pulsing effect. With the Hue Saturation Value node the colors can be changed, and you can mix them. A Noise texture for the Emission Strength gives an interesting effect.

For the glowing I've used two Glare nodes (Ghosts, low, 2 it. & Streaks, high, 3 it.) in the Compositor. In Eevee it's a bit darker compared to Cycles. But it works, looks not that bad and is a lot faster (~15sec vs ~2min).
Cycles render:

Eevee render:

The settings for the right ball were changed a bit. Both have a Point light in the middle now, and Material Settings > Settings > Shadow Mode is set to None. For the lights Custom Distance is activated and set to 3 m.
This is to fake the light in Eevee. It's ok as long as there are no noticable reflections in the environment.

Spot on. This is great! I will try this method! Can there be two right answers?

Maybe try it with Cloth simulation? Soft Body seems much heavier to calculate.
I've weight painted the body (not the tentacles) in order to create a group to pin in the Cloth > Shape panel. In the same panel, set a high Quality Steps value. Play with the Stiffness parameters: low Compression value and high Bending value. Maybe tweak the Internal Springs parameters as well? Then animate with some keyframes.

This is great. How were you able to model it so quickly? Did you select every other face and extrude?
Sorry, newbie here.

yes, I've created a cube, right click > subdivided it (then smoothed in the Operator box on the bottom left of your 3D view), inset the faces with double i, Alt E to extrude along faces, then extruded again, chosen Pivot Point > Individual Origins and scaled, etc

I got the model. I will play with the Cloth simulation to get it to animate correctly.
Thanks! Case closed.

@moonboots Nice tentacle ball! How would you UV unwrap it to texture it?

I guess it depends on what kind of texture I would put  ;)  If I texture paint, a simple Smart UV Project?


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How to describe an object in the camera reference frame?
I have an environment with a sphere, a camera and the sun. Both the camera and the sun track the sphere, such that they point always to the sphere.
All the coordinates are referred to the origin of the sphere. After all the object are place with respect to the sphere I need to obtain the coordinates of the sun with respect to the camera reference frame. This needs of course to take into account the rotation of the camera reference frame that changes every time the camera's position changes. I tried to look online but I didn't find anything.
How can I do this? Thank you so much

How do you intend to use the coordinates?  The answer would differ depending on the use.  For instance, if you need them in a material, you would use a Texture Coordinate Node and a SeparateXYZ node to get the relative position of each, but in a python script you would reference the transforms through each object's properties.

an example and/or some screenshots with annotations would help to make it clear what you want....because....i don't get it.


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MovieClipEditor : Load frames using a script when filesname are not enumerated
Got a folder of image files from time-lapse imaging which need to be read into the MovieClipEditor.
The filenames are not enumerated following blender's convention, and there's value in not modifying these.
The goal is to process the time-lapse images in Blender, namely apply Motion Tracking & Masking .
How could these be read to a MovieClip?
According to https://blender.stackexchange.com/a/210637/133653, it cannot be done.
My current Workaround is to create symbolic links to the source image files, and rename the links, so as these could be opened using the MovieClipEditor.
Would be great to have an alternative, internal within Blender and BPy-API.
This post, blender.exchange best-way-to-load-image-from-list-python-script, may be a good starting point. Could bpy.data.images be added to a MovieClip ?

Can you use a 3rd party app to assemble the images into video file that you could the load?

Thanks for your suggestion. Yes, these could be compiled into an .mkv file. For my needs the symbolic links workaround is a better fit -- hardly takes space and time to create; the symbolic links show reference to the source files, so it is somewhat self-documenting for later reference.

I think you'll find that to be less fragile than the extra steps you'll have to take to do it in Blender in python.


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My blender keep crashing after i change the rendering to GPU rendering from Preference tab
i was trying few different settings for blender for rendering but i end up having major crash and now my Blender is not working anymore. it keep crashing.
I changed the Rendering setting from normal to Open GL 3.3 i think this was the version (Blender 2.9.2).
after i done that i run a render and my GPU crash and the PC got restarted After that it start crashing.
i try to download new version but same
Here is the Error i am facing.
Can someone help Please.
Thank you

PS i was using AMD RX580 8GB

GPU is definitely not problem (speaking of type) because I am using the same at my home rig and it works fine with OpenCL and cycles using GPU. Did you actually tried to update or downgrade drivers? You didn't mention it in your question

Reloading or reinstalling won't change your preferences, and newer versions of blender auto save preferences by default, so it's probably  that the change you made causing the crash is still present.  Can you open blender and edit your preferences and redo the settings for graphics?


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Custom textures in new "Fields" Geo nodes
Does anyone know how to use custom image textures in the new Fields refactor of geometry nodes? There used to be a node called attribute sample texture, I cannot find the equivalent now. Thanks in advance!
Blender 3.0

I think there will be an 'Image Texture' node, it just hasn't been added yet.

Not every node has been converted to the new system yet

thank you, i was kinda hoping that was the case but couldn't find anything on the sub


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Colliding hair system with canvas for dynamic paint
I am getting decent with the UI, but still a blender noob.
Trying to make a working paintbrush for an animation. I want the hair to collide properly with the canvas and look like brush hair.

And no amount of experimentation has gotten me there. I've messed a ton of different ratios of

stiffness
pin goal
hair path segments
substeps

but still getting a stiff weird unreactive brush. My collisions with the canvas itself have seemed off, often the brush hairs pass right through the canvas, and collision modifiers have only sort of fixed that.

I figured out how to attach an object to the end of the hairs, in order to make dynamic paint work with the hair particles. At least I sort of did- proximity to the canvas of the end of the hair has been a problem because of the collision inaccuracies. As you can see I have proximity paint set way too high(.4) in order for the image sequence to show any paint at all.

I sometimes get kinks from the collision, at the base of the hair.
You can see the hairs pass through the surface of the canvas -
inner thickness=0.001
outer thickness=0.1

Possibly due to a conflict between particle weight and the hair dynamics?

This is the closest I've gotten on the realism front-
Segments=12
.44m length
30 quality steps
Pin Goal Strenth=7.0
stiffness=1.5
As you can see the kink is still an issue, and I don't seem to get any lateral splay of the hairs. Is this a pin goal issue?

The truth is I don't know what a generic setting for any of these parameters might be. Perhaps I'm way to high on pin goal or stiffness? Or low? It's seemed like any lower than this would cause air/gravity/inertia to cause the hair to hang in the air or float on it. I tried removing air forces, but didn't seem to make a difference, so perhaps that's an inertial effect? unclear. Or my collision thickness is too small for what I want?
So I don't really have a starting point, and don't know what's breaking the animation. If anybody could help me out with getting the hair dynamics anywhere close to functional that'd be amazing. I'd be happy to start the system from scratch if someone wanted to share any project settings from similar projects.
thanks for any help.

Have you increased the Path Steps and Strand Steps? This will make the bristles bend smoother. I made a while ago a teeth brush from the default cube, it might be helpful? Have a look here https://blender.stackexchange.com/questions/210108/how-to-make-toothbrush-bristle-animation

Path steps no? Not sure what you're referring to. I have messed with the strand steps at the top of the hair particle settings (2.90).  I don't think I ever tried anything higher than 20 or so, but that seemed excessive.
Viewport rendering for the hair in the photos I sent is set to 3, so they look janky there, the render is better, much smoother, but still has the kink in it.
The link you gave is great though, exactly what I was looking for. And I can see a couple places I'm way off of the specs you gave.  Thanks so much. I will report with my results.


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Scale and Transform nodes behaving incorrectly in compositor?
i'm working on an node-based algorithm for pixelating an image and then applying a dithering mask to it using the compositor.
the issue i've run into is very simple:
render image, 1536x2048
scale by half, to 768x1024 using scale or transform node
pixelate (all good, pixel perfect, at the expected size but surrounded by a transparent border, as expected)
scale by two, back up to 1536x2048 - at this point, one single pixel is missing along the right hand edge (+x) and top edge (+y), replaced by transparency instead
this shouldn't be a rounding issue, since both dimensions are divisible by two. furthermore, i've tried translating the result at the same time in order to avoid scaling around the center point of the image rather than the corner, to no effect.
i've also checked and this missing line of pixels is accompanied by a line missing about halfway through the image (as over the rest of the image, the enlarged 'pixels' for the pixelation effect are all correctly 2x2).
since there doesn't seem to be a way to directly write a new compositing node with shader code or python to directly read every other pixel, then apply my dithering algorithm (as I've done previously in UE4), i'm at a loss. is there some quirky way to make the scale node scale the image correctly? or does it just not work accurately enough?
thanks


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Constraint to glue two faces of two objects together?
I am creating an animation of a bending beam. I want the beam to have an object attached to its end, with the proper orientation. Considering that object is, for instance, a cube, the effect I am looking for would be that one of the faces of the cube is glued to one of the faces of my beam mesh, so that the position and orientation is corrected as I change the bending angle during the animation. The effect I am looking for is similar to the snap operation, but I cannot figure out how to snap the objects automatically during the animation, as the beam mesh is modified. Is there a way to do this?
An example of what I am looking for:

A clean and simple option for this is Vertex Parenting, the 3 vertex variety, to maintain orientation.


text:
Achieve blur-like glow effect in an specific object
I would like to learn how to make a kind of glow that looks good in well-illuminated environments, something like this. Any suggestions?

Apply an Emission shader to an object, move it on another render layer and in the compositor add a Glare node and set it to "Fog Glow".

I managed to do something similar following your advice of using different render layers, although I found that adding a Blur node in the compositor helped more to create the effect I was looking for. Thanks for the tip! :)


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Visual indicator for border of the mesh
is there a way to permanently show me what the edge border is?
In Meshmixer it's a blue color, in Softimage its turquoise.
It would be extremly helpful to discover doubled vertices, open meshes, wrong extrudes, or edges who got created by pressing 'F' instead of 'J'.
It always helped me a lot in modeling.
As an extra it would be helpful if I could select the whole edge with one double click like in Meshmixer (even if Meshmixer only works with polys).
Alt-Click doesn't always work and I just had a big 3D scan, which I cutted. I had to drive along the edge and CTRL+Click some times also worked.
I still have the feeling that this could be a helpful feature with not too much programming involved if step 1 is already there.


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Wrong depth for transparent geometry with a lot of layers
I'm trying to render models and composite them into an existing image with known depth. However, one of model I use has hair made with a lot of semitransparent strands. When I render it with Cycles, depth values for some pixel on the hair have depth as if nothing is there:

That causes problems with compositing: background it showing where hair should be (using "Z Combine" node). I've tried LuxRenderer, and everything works as expected there. Is there a way to get proper depth values in Cycles? I've tried increasing transparent bounce count (both min and max). It still renders noisy depth (and perf tanks, which is a huge problem).
(exr render: https://yadi.sk/d/unyMODQ5-atJEw)

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.

There's Alpha Threshold setting that controls whether semitransparent contribute to Depth, Mist, UV or some other passes. Setting in to 0 makes it so every hair strand no contributes to depth. That may not be a universal solution, but it worked well enough for case described in the question.


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Bevel not being generated on a shrinkwraped modified
I am trying to make a cutter tool out of a hiking path file through a mountain. Therefore I am using an imported GPX file, modifier of shrinkwrap on the mountain, and then have added a bevel from a plane / round.  However when I create the bevel, it appears to shrinkwrap everything (the solid) on to the mountain, so I am unable to create a cutting tool (via Boolean modifier)...any ideas on why this would be so?

I don’t understand. Are you trying to… I have no idea what you’re trying to do. A cutting tool? Is there supposed to be a tool that cuts a cross-section of mountain ranges on some thing, like a stamp roller?

yes please give some additional informations, do you have pictures of what you're trying to do?


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Toggle Render Image / UV Image
this is a basic question but I can't find any answer. It's driving me (a bit) mad.
When I press F12 the UV/Image-editor becomes my render-editor but how can I change it back to an UV-editor?
:)

If you want to stop render result from appearing in UV editor where you edit UVs change Display setting in render settings, see https://blender.stackexchange.com/a/3729/1245

It is your UV editor, it's just showing your rendered image.
See the image popup at the bottom of the pane, that says "Render Result"? Just click that, and select another image.

Yeah, that's the thing which is bothering me. It's kinda empty :(
https://abload.de/img/unbenannt357od9.jpg
https://abload.de/img/unbenannt47sqa9.jpg

Press the "X" to switch back from the rendered image.

@B.Y.O.B.: That works, although sometimes I want to switch to a different image instead of an empty editor.

@MatthieuO.: It looks like your pane header bar is gone. Is it there, but not in your screenshot?

I linked two images but the bar is only missing in the first screenshot but luckily I don't have any problem with the UV View itself.
I am linking again the image that is bothering me: the rendered image.
The Render Result is empty (and believe me: I created marked Seams and unwrapped the UVs)
https://abload.de/img/unbenannt4473qs2.jpg
Btw. Pressing X didn't work out.

What happens if you render the image again?


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How do i tell blender to render image after 3 sec everytime?
I want to animate a 100 light which turn on one after other.
How do i dothat in blender.
Please help.
Thanks

I think you will need to add some more details to get a helpful answer, not sure exactly what you are trying to do

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


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GPU rendering error
enter image description here
Hi,
How do i start GPU compute while Rendering.
i am using AMD READON GRAPHICS CARD R9 360 BUT BLENDER 2.79v is not reading my graphics card.
PLEASE hELP

If I am not wrong about this AMD cards are not supported yet ... it's a bummer I know. Go nvidia! ... the manual says this ... Cycles has two GPU rendering modes: CUDA, which is the preferred method for Nvidia graphics cards; and OpenCL, which supports rendering on AMD graphics cards. You can try to see if switching to OpenCL helps

... more on this on the page "OpenCL is supported for GPU rendering with AMD graphics cards. (We only support graphics cards with GCN architecture 2.0 and above). To make sure your GPU is supported checkout" So do check if your card is GCN architecture 2.0 read here https://docs.blender.org/manual/en/dev/render/cycles/gpu_rendering.html


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Denoise is not showing in the Scene tab
I am using version 2.79, yet the Denoise option is not showing in the Render Layer Scene Tab.

Looks like you're using Blender Internal. Denoising is only available with Cycles Render.
You can change the render engine in the info header at the top of the window:

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


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Tank tracks/treads breaking when rotating hull
I am working on an m1 abrams model and I plan on using it in an animation but I have encountered a problem.

I've parented the bezier circle to the hull and all works well when the tank is going straight, but then... i tried rotating it...

Its probably some amateurish mistake but I'm new and i cant find a solution.
googled it, the answers were mostly years ago so I'll also contribute by having a newer thread to look by everyone else

Is you project for video or an authentic model?  I've done this with a full mesh solution, and also one that fakes the track-plates' animation.  Both come out ok for video work, and both render in OpenGL so a lot of experimental rendering can be done very quickly. The  problem is, a fair bit of experience will be required, particularly for the mesh solution and a full answer will take a lot of typing.  I've been holding back to see if someone else will come up with a smarter ( and easier) method.  (I'm still using vers 2.77a)

PS to the above - If no one comes up with something you can take the experimental blend files and have a look if you think that might help.   I can embed a quickie text-file explanation in each.

@Edgel3D Expermental blend files? sorry for such a slow reply I was working on a new project and expermenting.

Noted your reply @NlaEid.  Will get back as soon as I can.  Is this for a video project or game?

Hold the Presses @NlaEid !  I knew there had to be a better way...  Have deleted the workaround answer and substituted with another, which you'll find much easier.  My original tank tracks made years ago suffered  the same problem as yours, hence the workarounds.  I've been chewing over the reason why the screw effect and have come up with the simple answer - we just put them together wrong!  See how you go with the current solution. (see below)

Edit 13th Feb 2019 - Added Blend file for a query in 'Blender Artists'.
-===============-
The answer is in the way it's all put together, particularly the Origin points.  The Curve, Tracks and Empty must all share the same OP.
The steps below (deleted) cured my original tracks that I'd made ages ago and like yours, suffered badly with the screw effect when rotated in the Z axis.
I did this one with a single track, and duplicated it after.

The Details -
Delete all parentage and also delete the Empty.
Select the tank tracks and remove the curve modifier.
"Apply" the array modifier as it stands.  (make it solid)
Set the cursor to 0,0,0 with ShiftC,
Select the tracks, press ShiftS --> "Selected to Cursor".
Select the curve, and do the same (ShiftS)
With the tracks selected again, replace the curve modifier.
Add an empty with ShiftA.
Parent the tracks to the Empty
Parent the Curve to the Empty.
That should do it - you can rotate and move the Empty now without ill effects...
If this hasn't worked the 3D cursor may have been inadvertently moved from location 0,0,0.


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Cannot see imported models
Whenever I import this model into blender, I cannot see it, regardless of what format I convert it to. The vert count immediately jumps to 30,000 or so, so it's there somewhere. Its origins are all at 0/0/0, and I have tried the following:
- Making sure the rendering engine renders it as solid
- Pressing . to zoom in on it, which only put my user camera in an inescapable hell
- Scaling it up and down by absurd amounts
- Manually zooming in
- Converting it to many different formats then importing again
I have no idea what else to do; any help would be much appreciated! I'm likely missing something very obvious...

I might try adjusting your object's scale, position, and origin.
The transform properties panel is your friend. If you don't have it active toggle it on by pressing T. At the top, you can view and change the position, rotation, scale, and bounding dimensions of your object. Using the Dimensions section of the panel, you can tell if your object is really big or really small. By setting one of the dimensions (let's say the X dimension) to 1.0 to 8
.0 or so, the object should be able to fit into your scene well. Then you can copy the X scale value into the Y scale and Z scale boxes to proportionally resize your object.
Quick Fix:
First try resetting position with Alt+G. If you still don't see your object, but you see its origin, it may be really small (in which case you can play with the scale) or the origin may not be the center of your object. To reposition the origin of your object, in object mode, choose Object > Transform > Origin to Geometry, then reset the position again.
Once you are satisfied with the size of your object, press Alt+S to apply your scale changes.
Another approach is to work in edit mode, selecting all your vertices by toggling A (you can see how many verticies you have selected at the top of the viewport) and pressing Alt+S > Selection to Cursor to move all your geometry to the 3D cursor position, then scale appropriately.

The model is 25,800 BU wide (far beyond the default 1,000 BU clipping). Furthermore, their Origin is somewhere behind the building.  Selecting every object via the outliner, then scaling them 100 time down (S.001), should give you something more usable.


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How can I create feathered edges on a circle?
I have a circle mesh that I'd like to be opaque for most of its surface, but slowly fade to transparency at the edges.
My current node setup is this:

But my result is a mostly transparent circle that is more transparent around the edges:

Any small adjustment to the "Blend" setting causes the preview sphere to become either pitch black or invisible. Even if I did find the correct setting, I don't think it'd work properly because I'd like it to be only the edges that fade, not the entire circle.
The end result I'd like is closer to this (badly photoshopped):

Any help you can give is very much appreciated!

Try to use a gradient texture (quadratic sphere) completed by a color ramp (ease).

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

I want to texture this effect so that only some areas have the effect where would I place the texture? If I can't figure it out I'll ask it as an actual question.


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Exported file not move like in the blender animation
I created a simple low poly character and I animated using blender.
When I play the animation in blender it looks fine.. no issue...
see image:

but when I exported in glb or glTF format .. something is wrong!

I cant'understand why.. I used the constraints childof to follow the Head movement on the animation since the Hat is a different object.
What I'm doing wrong?

I don't think the "Object Constraint" can export to glTF format.  You may need to make the hat part of the skinned mesh.

Hello. What version are you using? Please upload your test file on a issue on https://github.com/KhronosGroup/glTF-Blender-IO


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How to assign a material to a single face of a mesh using Python API
I have tried the following but the mat is not assigned to any of the faces.
import bpy
import bmesh

# Creating a new Mat
mat = bpy.data.materials.new(name="newMat")
mat.diffuse_color = (0.5,0,0.5,1)

# Generating a Box
bpy.ops.mesh.primitive_cube_add(size=2,  enter_editmode=True, location=(0, 0, 0))

# Resizing and Translating the box
bpy.ops.mesh.select_all(action='SELECT')
bpy.ops.transform.resize(value=(0.5, 1, 1))
bpy.ops.transform.translate(value=(0.5, 0, 0))
bpy.ops.mesh.select_all(action='DESELECT')

# Instantiating the bmesh of the Box
obj = bpy.context.edit_object
me = obj.data
bm = bmesh.from_edit_mesh(me)

# Selecting just one of the faces
bm.faces[0].select = True

# toggle to edit mode
bpy.ops.object.mode_set(mode='EDIT')

# make sure face select mode is enabled
bpy.context.tool_settings.mesh_select_mode = [False, False, True]

# use second material slot
ob = bpy.context.active_object
ob.active_material_index = 1

# assign the material
bpy.ops.object.material_slot_assign()

# toggle to object mode
bpy.ops.object.mode_set(mode='OBJECT')

What am I doing wrong, or how else could I achieve this?

@MartyFouts hi, thanks for shareing. Actually I tried that answer, I should have mentioned in the question that most of my code have been taken from the accepted answer, but in my case the mat is not being assigned. That is why I posted my version

No problem.  In the future, you should mention the specific answers you have tried and why they didn't work for you.  The answer from the question should work, but the code you shared is missing some of the  steps. Someone has already posted another way of doing it. If you want to see your code fixed, let me know and I'll post an answer with working bmesh-based code.

You can assign the materials using MeshPolygon.material_index in Object Mode without Bmesh.

import bpy

def create_material(mat_name, diffuse_color=(1,1,1,1)):
    mat = bpy.data.materials.new(name=mat_name)
    mat.diffuse_color = diffuse_color
    return mat

# Generate 2 demo materials
mat_red = create_material("Red", (1,0,0,1))
mat_green = create_material("Green", (0,1,0,1))

# Generating a Box
bpy.ops.mesh.primitive_cube_add(size=2, location=(0, 0, 0))
# Resizing and Translating the box ...

# Get a reference to the object in context
obj = bpy.context.object

# Append both Materials to the created object
obj.data.materials.append(mat_red)
obj.data.materials.append(mat_green)

# Assign the green Material to the second polygon
obj.data.polygons[1].material_index = 1

# Assign the green Material to the 4th polygon
obj.data.polygons[3].material_index = 1

Related:

Python - Set material to material slot
2.93.4 Python - apply an image texture to part of a mesh
How to assign a new material to an object in the scene from Python?
select specific face by its index

Thanks, very informative, I will give it a try Today and let you know

Thanks, this is what I was looking for

If you'd like to assign material(s) to certain faces in Edit Mode, just assign the index of the material slot to BMFace.material_index on a Bmesh representation of your mesh:

import bpy, bmesh

def create_material(mat_name, diffuse_color=(1,1,1,1)):
    mat = bpy.data.materials.new(name=mat_name)
    mat.diffuse_color = diffuse_color
    return mat

# Generate 2 demo materials
mat_red = create_material("Red", (1,0,0,1))
mat_green = create_material("Green", (0,1,0,1))

# Generate a Box
bpy.ops.mesh.primitive_cube_add(size=2, enter_editmode=True, location=(0, 0, 0))
# Resize and Translate the box ...

# Get a reference to the object in context
obj = bpy.context.object

# Append both Materials to the created object
obj.data.materials.append(mat_red)
obj.data.materials.append(mat_green)

# Bmesh representation
me = obj.data
bm = bmesh.from_edit_mesh(me)
bm.faces.ensure_lookup_table()

# Assign the green Material to the second polygon
bm.faces[1].material_index = 1

# Assign the green Material to the 4th polygon
bm.faces[3].material_index = 1

# Optional
#bmesh.update_edit_mesh(me)
#bpy.ops.object.mode_set(mode='OBJECT')

You might want to create the mesh using Bmesh in this case as well: how to use BMesh to add verts, faces, and edges to existing geometry


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2.93.5 - only Grab and Snake Hook tools working correctly in Sculpt
I uploaded 2.93.5 update to my MacBook Pro mid-2012 running macOS 10.15.7 today.  Now only the Grab and Snake Hook sculpt tools work as they should.  Some draw tools appear to have some impact on the the default sculpt mesh but only insofar as a form of smoothing.  Alt+ selection makes no difference to the tools.  I have turned Dynotopo on and off, reset to factory defaults and tried reboots and new files but there is no change. The same is happening on 3.0 Alpha which I downloaded after.  This problem did not occur in 2.93.4.  Any explanation of the possible problem would be much appreciated.

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.

I am unable to use any of the sculpting tools in Blender version 2.93.4 or 3.0 Alpha with my Huion Inspiroy Q11k. The latest driver has been loaded for the tablet but still no change.  The only way I can select any of the sculpting tools other than Grab and Snake Hook is to use the trackpad on my MacBook Pro mid-2012. I have been unable to find a reason or a solution and Blender appear to be unable to resolve the issue either.


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Can I animate the 'strength' in the Displacement modifier?
Is there a way to keyframe the 'strength' of the displace modifier at different stages?
I am trying to animate a surface, and the best results/animation I'm getting are through the strength modifier. I know I can animate through creating changing variables and key-framing them in the 'texture' panel, but these aren't giving me the results I'm looking for. :( In the photo below, I've shown the displace modifier and the 'strength' is the bottom right slider:
I'm still a bit of a beginner on Blender, so any help would be really really appreciated!
Thank you!

to keyframe the strength, put your cursor over the value and press "i"

You can add keyframes to any setting that has a small dot that when you hover over shows Animate Property

If you Left click the dot or hover over the input field and type I a keyframe will be added at the current frame in the timeline.
Move the timeline to a different frame, change the value, use I or the dot to add a keyframe and you have an animated property.
Note:  Some properties can accept keyframes but still won't generate animation.  Those are mostly in the "Legacy Texture" panel.  Displace modifier strength can be animated.

Thank you!! I don't have the dot next to my Strength slider so I didn't think it was possible - this has really helped! Thank you very much!

You're welcome.  Which version of Blender?  Before 2.9 a lot of properties could be animated but there was no indication.  I don't recall exactly when the overhaul that marked properties with dots happened though.  Could have been 2.83 or earlier.


text:
Using Lego Digital Designer and Blender
From what I heard, I think that the Lego Movie made their lego models in LDD, and than exporting the models to Maya, and using maya to make subsurf models.  I think that they found a way to make their subsurf models automatically be placed in the correct place using data from LDD?  Does anyone know how to do this?  (I realize it's a hefty topic)

Lego Digital Designer allows to export ldraw files. You could try the following add-on (I haven't tested it): https://github.com/TobyLobster/ImportLDraw

the addon works really well!  This may solve all my problems! I'll leave the question open for now, in case I need to make any manual parts.

According to the Lego Digitial Designer manual it allows to export LXF, LXFML and LDraw files.

Export. Export lets you create LXF, LXFML and LDraw files that can be
  opened in other applications

There are community developed Blender add-ons such as ImportLDraw by Toby Nelson that allow to import these models.

I just realized that the addon also adds a bevel modifier to each piece, and it makes a great result. :)

I'll award the bounty to you when i can, it won't let me yet

Glad that it's what you're looking for. No problem. BTW his name seems to be Toby Nelson not Lobster, at least according to his profile: https://github.com/TobyLobster The lobster is just part of his username.


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What's the best way to export from Lego Digital designer to Blender
The Question pretty much says it.  My purpose is animation. I want the ldd model to be exported as individual pieces.  I've exported from mlcad before, and it exported as several objects for each lego piece.  that's a mess for animation.  I think I will probably need a 3rd party program for it as ldd doesn't export to obj, fbx, or any other format.  Which program should I use?

I found that exporting a Ldraw file from ldd, and importing the ldraw file into blender using TobyLobster's LDrawImport addon worked really well.  The addon can add the word Lego on every stud, and it adds a bevel modifier to the object among all the other things.


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Anyone know of a plugin/method to sort/organize organic objects into "tightest fit" with least amount of negative space between them?
Does anyone know a way to take a collection of organic/randomly shaped objects and sort them (ie. move and rotate) in a way whereby the least amount of negative space is between the objects, within the containing hull of all objects?
For example, laying out rocks where there is minimal space between the shapes:

For 2D objects you could use UV packing. For 3D objects I think it's very hard, a many months long project.

UV Packer or similar could be perfect. Thank you!!


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Inset Square From a Rectangular Face
I was just checking out a tutorial made on 3dsmax and i saw something really nice.Ill post pics
The guy inset this rectangular shape face,and makes it square with some hotkey(i dont speak good english but he calls it something like "regularize")
Is there some way to do that in Blender too ?

There isn't direct way to inset a face without taking into account proportions of the parent face, however you can use addon to workaround that.
After inset use Circle option of the LoopTools addon (addon comes with Blender by default; addon should be activated in User prefs). Operator will likely rotate the face, you will need to rotate it back so that it fits parent face (if the resulting face is oriented unevenly in the global space you should rotate it around its normal to avoid distortions).

If in 2.79 this will be in W menu > LoopTools. In 2.8 it depends on preferences you set for selection mouse button (right or left). By default, it should be in the Right click menu.
Note that Circle operator isn't generally designed for equalizing proportions of faces rather it does what its name suggests - converts selection to circle. As the face in this case consists of 4 vertices it works as expected. If you were insetting Ngon this way would created a circle.

Flawless thank you !


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Geometry Nodes Not Appearing When Added to Object - No Group Attributes
Edit
I've redone the tutorial for the third time and the problem has persisted. However, I think the issue is the "No group output attributes connected" error that shows up below the Geometry Nodes modifier. When trying to apply weight paint to the object surface (The "Icing") there is no option to alter the density to that of the weight paint, I assume because there is no assigned group. How do I solve this issue? So far I've tried: recreating the sprinkle, setting the sprinkle's origin to geometry, and assigning the sprinkle to the icing by list and by dragging the object from the menu into the geometry node work area.
While I'm still not sure why this issue is occurring, by redoing the tutorial from the start and then by setting the cylinder's origin I now have more than one sprinkle! I just turned my density up to 800,000 for now, until I can figure out why this is happening.
I followed the advice of the answer and have redone this part of the tutorial, which has improved my results! So thank you very much! But I'm still encountering the same problem, just with marginal success. I now have a handful of sprinkles if I turn my density up to 50000, but it isn't nearly what I need.

Original Question
I'm following the Blender Guru donut tutorial for 3.0 and I 'm having issues on Part 9 - Geometry Nodes.
And the first issue begins when I attempt to add the Distribute Points On Faces node to my geometry nodes.

In the tutorial, adding the Distribute Points on Faces node causes large, sharp geometry nodes to appear on the object. My object disappears when I add this node.
I decided to keep going in the tutorial, although I think this is the root of the problem. The next step in the tutorial is to add the Join Geometry node, which I do and this brings my object back into view.

After that the tutorial had us model the object that was going to become instances on the base object. We did this by adding the Instances on Points node and then dragging the object that will become the nodes (in my case a cylinder named "Sprinkle") into the Geometry Nodes work area, so we can use its shape.

Then I was supposed to get the geometry of the "Sprinkle" to be the node on the base object, but even when I linked these nodes it didn't appear.

I upped the Density to 100 and the seed count from -50 to 300, but nothing appeared. So I looked for a solution and found that I should apply the scale of my node object (the "Sprinkle") to get it to appear. I tried this next.

However, as you can see, nothing happened. But I figured out that I can cause one sprinkle to show up if I put the Density between 300-800 and the Seed Count to 1. Anything outside these parameters and it either doesn't react or the single "Sprinkle" vanishes.

What went wrong and why? I'm very new to Geometry Nodes.

you have several objects here marked as "not visible" in viewport: [1]: https://i.sstatic.net/1yRqM.png so just click on the eyes and put them on. if problem is solved, great. if not, pls provide blend file

It seems to me that all your objects are created in a microscopic scale. Can you please check the N panel to see what the dimensions of the donut are?

If you watch a tutorial and do not get same results as what's shown in it, it is best to just start again from the beginning and follow the instructions more thoroughly. This is kind of standard solution that solves pretty much all problems with something not working same as in a tutorial.
It is worth noting that geometry nodes are actively developed at the moment so you should also make sure the tutorial is for the exact same version of Blender as you are using so you have the same functionality as the tutor.

Thank you for this wonderful answer to this question. I am sure it is the solution to 20% of the Geometry Nodes questions asked here, which is why it should be permanently pinned to the top of the list!

This kept happening to me, I checked the error in the geo node modifier and it said no group output attributes connected. Then i realized it made the group input and output already for me and i just needed to zoom out super far to see it was below my view.

I am also a novice at blender and was facing the similar issue.
There was a comment in the same tutorial which might solve the issue you are facing (it solved mine).
Make sure the Sprinkle's origin is set to its center.
(Right click original sprinkle>set origin>origin to geometry)
I hope that solves the issue.

Thank you for the answer! I just did that and nothing changed, but it is a good tip to keep in mind in the future when I make new meshes.