text:
Node for local mesh curvature
Is there a node (or group of nodes) that outputs a measure of local mesh curvature?
Using the input Fresnel node almost gives me the effect I'm looking for, but the node setup I'm looking for would be unaffected by viewing angle.

What about the Normal output of the geometry node?

@gandalf3 I think the amplitude of the gradient/derivative of the Normal map is what I'm after. I'd like to be able to distinguish regions that are curving from regions that are flat.

This feature was added recently and should be in 2.74.

This attribute means how "pointy" the geometry surface is, which
  allows to do effects like dirt maps and wear-off effects on render
  geometry. This means the attribute is calculated for the final mesh
  which means no baking (which implies UV unwrap) is needed. Apart from
  this the behavior is quite close to how vertex dirty colors works.
The new attribute is available as an output socket of Geometry node.
There's no penalty for the render time, only some delay on scene
  preparation (the delay is linear of the mesh complexity).


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Drag & Drop custom mesh formats into viewport
I have an add-on for importing/exporting a particular mesh format. Is there a way I can have drag & drop of this file type from the file browser into blender viewport automatically trigger my import add-on on that file(s) ? (similar to the way the drag & drop image into the viewport works).
Currently other import/export formats do not seem to work by simply drag&drop into viewport (e.g. obj, stl, dae).
Note: sure, some of these import add-ons provide additional settings before import/export, and one could argue that drag&drop is not useful, but still in some cases it can still be useful when predefined import settings can be assumed.

source: Stack Exchange

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

sort: votes


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How do I make an export addon pre-populate filename with name of the selected object?
I’m creating an export/import add-on (similar to STL import/export add-on) and I would like the suggested filename in the file browser to take the name of the currently selected object in the scene or a generic filename if multiple objects are selected. My add-on uses the bpy_extras.io_utils’s ExportHelper.
In the example below, for a new, unsaved blend file, the default filename is untitled.sur (sur is the extension the file exported by my addon). I would like this name to be “Icosphere.sur” since the object “Icosphere” is selected in the scene.

Set in the invoke method.
As noted in these answers the IO helpers have invoke and check methods that are doing some things behind the scenes.
https://blender.stackexchange.com/a/198924/15543
https://blender.stackexchange.com/a/207665/15543
The export helper invoke method, that if not set sticks in the name Untitled, simply change this to that of the context object.
def invoke(self, context, _event):
    import os
    if not self.filepath:
        blend_filepath = context.blend_data.filepath
        if not blend_filepath:
            blend_filepath = context.object.name # <=== UPDATE
        else:
            blend_filepath = os.path.splitext(blend_filepath)[0]

        self.filepath = blend_filepath + self.filename_ext

    context.window_manager.fileselect_add(self)
    return {'RUNNING_MODAL'}

This method is defined in the internal blender scripts..so they can’t be changed (or rather should not). do you mean I can overload this method in my addon class inheriting from this helper class and do whatever I want to do in it to set the file path ?
Btw, I ended up ditching the helper class and just defining the invoke method in my class directly.

Congratulations that was the idea. Thanks heaps for the feed-back.

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


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Painted wood on surface
Is there a way to make a painted material from the picture below? All answers are welcome.

I know it. So, the image texture for the base colour is using a ColorRamp node, linked into a Principled BSDF node.
Here is a screen capture of the nodes:

and the preview photo:

what do you mean exactly? Can't you use it in an Image Texture node?

I wonder how they moved my answer to the question.

iKlsR has edited your post but he lost your original picture, you can edit it again and add it if you want

Do you still need help with this, @22melloja? If yes, can you specify what's the issue? You seem to have managed to get the colors working, you only need to keep tweaking the ColorRamp to get the desired contrast. The Mapping seems weird, but we'd need to see the UV, plus Texture Coordinates and Mapping nodes to see what's going on. Edit your question this time to add the information.

There! @Rhaenys


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Acheiving Slit-Scan in Blender's Compositor
Is there a way to make a slit-scan technique effect in the Compositor?

https://www.instagram.com/p/BV3G1tYF5Q-/

it is not a blender solution but I came across this ffmpeg link a couple of days ago that may give you the result you need, https://oioiiooixiii.blogspot.com/2017/11/ffmpeg-temporal-slice-stacking-effect.html

You can use textures as vectors to distort your image. May be a simplier node setup exists but this works.


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Making a realistic canvas material
How could I make a canvas shader in Cycles as shown in the picture?

Hi. What have you tried and where are you getting stuck?

@RayMairlot, I have an answer that Nicola gave me on the bottom of mine.

I'm aware of that. My point is, on this site we prefer questions where the user demonstrates that they have at least tried to accomplish the task. This is so that a) We can see where specifically in the process they fail (because this site focuses on specific questions with specific answers) and b) Reduces questions which can come across as "Do this for me".

It's not clear whether you are looking for a procedural way or a texture-based material would be fine.
If using textures is ok, there's a white fabric material on CC0Textures here that you can use like this:

Wow! That seems perfect, thanks. I'm gonna use it in my project. :-)

You don't need to do much here. You can use a default material that is only a Diffuse BSDF shader and get pretty convincing results.
Canvas material has some reflectivity and surface texture, but these can be seen only in specific conditions - when there is a strong light source that is reflected while you are looking at the surface at a grazing angle and when you are looking at it from a close distance. It is not usually distinguishable in most renders, so simple diffuse material is an option. You could add a Glossy BSDF with some roughness and mix it with the Diffuse BSDF with Fresnel node using IOR of something like 1.3 - 1.5(acrylic coating) and add some bump using an image texture of some fabric or you could mix 2 Wave Textures rotated at 90° angle to each other. This is not visible in your reference photo so you probably do not need that.


text:
Fabric material (coloured)
Does anyone know an idea to accomplish this from the picture?

(source: emancipath by Zeitguised)

Use a wave texture except use no ondulations. Put texture coordinates to object (so it will use a triplanar texture space).


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How to create a "Airbrush-like" Shading Material
How could I make a material out of the following picture?

and also the Glossy one?

EEVEE only answer!

As it's hard to create such material in Cycles as you posted above, it's fairly easy to achieve it in EEVEE (for now only in Blender 2.8 Alpha 2).

For Cycles answer you can check here: Is there really a way to make a true toon shader material in Cycles? Many nice examples provided.
Node setup and overview.

We are using here Specular BSDF to get simple shading and convert it to colour through Shader to RGB. From it we are making two "channels" for separated highlights and shadow using Color Ramps.
After that we are combining those "channels" with Noise and then mixing them to get final "mask".
At the end we have Color Ramp with our colours. From left: shadow, main and highlight. And connect it to Emission shader.
Optionally you can add some Contrast or Saturation, or anything to improve result.

I might use Eevee in Blender 2.80 Alpha 2. Thanks!

This is how I would do it in Cycles (Eevee).
Since you need to break up that blue color with spots it better not to use the principled shader. So I just took 2 diffuse nodes with the blue and green color and used a gradient texture with a color ramp to control to fall off.
Mix that together with a glossy node for the shine. (If you want to take the shine off, connect the 2nd mix shader directly to the output ("no gloss")).
Then play with all the nodes I circled. Those will control how big the spots are and how you want the falloff to look.
Hope this helps a little.

This one I just added a bump node (circled) to give you the bumpy look if thats what you are after.


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Blender 2.83 Cant see particles in render
I am brand new to Blender coming from Maya and I can't figure out why I can't see my particles in the render. Am I missing something?
The Emitter, Domain and Collision Object all look good in the Viewport, but the Render View does not show any particles. I needed foam and spray.
Thanks

first guess, did you assign any material to the emitted object (not the emitter object)? Particles do not need domain, as domain is mainly for fluid and smoke simulations. You should share the blender file so anyone could help you out.

Try to cache them: https://blender.stackexchange.com/questions/165625/2-81a-particles-in-render-not-matching-preview/165640#165640

I have the same problem as @paulepc; i searched already around and even cam across a post stating that cycles does not support particles (scratch head)... Simple setup: http://www.filedropper.com/noparticles   - added particles and clicked bake; i tried different setups (create cache on disk, etc but non of the render engines render the particles - yes I also tried adding a material). What else could i try? Maybe someone could have look at the blend file...

Ok, in my case the problem was, that i choose under rendering: halo - watch this until about 2:55 min and you will know what to do: https://www.youtube.com/watch?v=gepD8FgcXJQ

I just changed my emitter to Plane and that solved my problem.


text:
Ways to animate edge loops sliding along a torus knot
I'd like to animate a torus knot, making the edge loops (selected below) move forward along the knot:

The method I'm currently trying is edge sliding all of the loops forward as a shape key, then animating the shape key. After the slide, the mesh should look unchanged, however the edge loops are on top of where their neighbour used to be.
A simple edge slide on the loops doesn't slide them all in the same direction; some loops slide forward, and the others backward.

Is there a way to slide all of the loops in the same direction? Is there a better approach to achieving this animation effect?

Select half one then half?

It's not clear to me yet where the "splits" in direction are - there can be more than one, and it seems to depend on where the mouse is when the slide starts. I think doing it in multiple operations is going to be a pain in the neck.

Are you trying to achieve a seamless animation using Vertex Colors ?

I am trying to achieve seamless animation, though I haven't thought of using Vertex Colors (nor do I understand how that'd work).. I was thinking I'd keyframe a shape key with linear interpolation and a cycle modifier.

so if the end result can be produced without shifting the vertices that would be OK? Sometimes knowing the desired end result helps streamline the path to an answer.

It appears that you can't do this directly, however I am writing an answer for a work around right now.

My goal is to get to the seamless animation, so I s'pose I don't actually care whether or not the best route is moving the edge loop; I just want that animation! I'll update my question, if appropriate.

Posted my answer, hope it helps and solves your issue.

Maybe adjust the title of the question, to reflect what you really want rather than focussing on an intermediate step? That way people looking how to animate something like this will actually have a chance at finding an answer. In the format 1) this is what I want 2) this is what i'm trying, are there better ways?

Sadly you can not do this directly, however you can achieve the same result fairly easily. Begin by selecting one longitudinal edge loop, and pressing P > By Selection. Now (in object mode) delete the old mesh. Next select the new edge loop mesh, and press Alt+C > Curve from Mesh/Text.

Now you can create a cylinder, add an array and curve modifier, and you have the desired result. You may need to scale and adjust your cylinder mesh slightly to fine tune it.

Simply animate the mesh's position (on the Z axis) to animate the edge loop sliding effect, and add your wireframe modifier to complete the effect.

And this is what the final result will look like:

The array modifier has been disabled to show the animation more clearly.

With the torus loop closed, I don't suppose there's a way to merge the first/last edge loops?

Yes, enable Merge and First/Last on the array modifier.

You sure about that? The array modifier has to come before the curve modifier, so the vertices aren't close yet.

Oh right. Hmm . . . I don't know then.

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


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Highlighting parts of objects throughout animation
I'm making a technical animation to supplement a training document for a lab procedure.
I'd like to annotate the video by highlighting objects (or parts of objects) to draw attention to specific details. There wouldn't be any motion throughout the animation, so motion tracking wouldn't be an issue.
For example:

How can this be achieved within blender?

Good points, thanks! As for built-in vs post-processing, I'm not sure. Whichever way makes more sense, I suppose. I find my animation projects are messy and difficult to navigate as it is, so adding the annotations would just make matters worse. I'd be open to built-in, if that's what makes the most sense.

Unrelated: You seen Reynante Martinez's brain shader? it may be worth looking into. if that's a brain... cause I think it is...

@RadishoftheOpera yeah, I love it! Reynante is a wizard :) When I try to recreate materials like that, it usually just leaves me frustrated that I can't come even close :P So I tend to go for simple stuff that looks fine, rather than botching an attempt at amazing.

While you can animate the material colours as others have suggested you can also composite the change using masks.
Masks can be created in the Movie Editor for existing videos or in the UV/Image Editor if you just want to align a mask to the current render result or image. If your items were moving then you could animate the mask in the Movie Editor to follow the items, you can even parent them to motion tracked points instead of manually positioning each frame.

The bonus with compositing is that if you have already rendered the video or want to adjust an existing video it is much quicker than re-rendering the whole animation.

You can simply animate the colour of the material of your object, maybe with the emission value also.
Create copies of the material, one for every part to be highlighted, then animate the colour and the emission value.

To clarify: it is possible for one mesh to have multiple materials, and you assign those materials to the appropriate polygons.

You can keyframe colors for a shader by tapping i while hovering the mouse cursor over the color field.  This works for most, if not all, value fields in various areas of Blender.
Once you add a keyframe, the color box will have a yellow border.  Now when you move the Timeline slider, the outline will turn green to indicate that a keyframe has not yet been set for this new position.  You can change the color and then press i again while hovering over the new color to set the color for that frame.

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


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Per-Viewport Settings vs Global Settings
When there are multiple viewports active in the UI, it seems that some settings apply per-viewport, while others apply globally.
Examples of per-viewport settings:

shading mode (wireframe, solid, rendered, etc...)
transform manipulators
Visible layers (after finding the "unlock camera and layers" button)

Examples of global settings:

Object interaction mode (i.e. object mode, edit mode, weight paint, etc..)
Pivot point
Edit mode's selection type (i.e. vertex, edge, or face)
Edit mode's visible/hidden vertices/edge/faces

Is there any way to get the global settings applied per-viewport? For example, could one get one viewport in edit mode while another is in object mode? Is it possible to have one viewport in edit mode selecting vertices, while another is selecting faces?

My question is more general than that one. The ability to unlock layers addresses part of it, but I think the answer to this will be about telling the difference between options that have an "unlock button" and those which don't.

I'm bummed that this is considered a duplicate :(... Would the question be better if I ripped out all but the last two sentences?


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How to Respond to File Selections in a Blender Add-on Using the File Browser?
I'm developing a Blender add-on that uses the built-in file browser. I want to update the property panel with information related to the selected files. For example, when a file is selected, I want to display the number of lines in the file on the property panel.
How can I make my add-on respond to file selections and unselections in the file browser so I can update the file info on the property panel?


text:
Can custom nodes be written for the compositor?
Is it possible to create a custom compositor node using python? I'd like to be create the following node:

Input sockets for Image and Z render results
Load the image into numpy arrays
Manipulate the numpy arrays in various ways
Output socket for resulting image.

I've been able to create a new node type and register it the with the CompositorNodeTree, but it doesn't actually do anything. Is there a method I can implement (e.g. process or something) that can trigger the node process the image?

I`m also looking for option to build simple node that input chosen object transform for further post process in the compositor.
OSL or other custom shader solution for the compositor would be nice.

While it is possible to define a pynode that can be added to existing node trees, they are considered unsupported and have limited functionality - mostly they don't get an event to automatically update. I don't think anything has changed since this previous answer.
The two main pynode projects are animation nodes and sverchok - both of these projects have implemented bpy.app.handlers that trigger an update of their node trees for various events. You will need to experiment to see if you are able to get some results using one of the render related handlers to update your node, but I don't think that any of the handlers fall between rendering and compositing.
Depending on your needs, you may be able to use a script that renders a frame, updates your node to get the result and then save the render result or viewer node output.
You may also want to try manipulating the render after it is completed instead of during compositing.
bpy.ops.render.render()
img = bpy.data.images['Viewer Node']
w = img.size[0]
h = img.size[1]
arr = np.array(img.pixels[:])
arr = arr.reshape((w,h,4))

Is it possible to add existing nodes to a custom pynode tree? For example, use a cloud texture output?

@VSB no. But you can access the same algorithm and use it in your nodes. You will find it in mathutils.noise

Not through python, no. Since Blender is open source you could always code a custom node like the built-in ones and recompile Blender itself. But there's no functionality for adding new compositing nodes at runtime through plugins or scripting or anything like that.
The node you created (and any nodes created via Python) are merely UI elements. They don't actually process data, they are visual representations of some other thing that will do the processing. The python nodes API is meant primarily to allow addons to add their own node editor pages for whatever functionality they need to represent to the user with nodes. Due to the way the API works it's also possible to use it to make custom nodes show up in the compositor or BI/Cycles shader trees. There is no way to supply the actual "business end" of such a node though.

the link seems to be broken. got a new link?

https://archive.blender.org/wiki/index.php/User:Nazg-gul/WritingNewNode/

Someone has compiled a version that would allow you to write your own Python scripts to process images in the compositor without recompiling:
https://github.com/bitsawer/blender-custom-nodes
I find it really useful. However, the number of input/output nodes appear to be fixed. I would really like to see this feature in the official release.


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Cycles texture on sphere to follow sun rotation
I'm trying to make a cycles material for a planet in space, and I'm having trouble separating the dark-side of the planet from the light-side. I'm trying to relate it to the rotation of a sun lamp, such that I can mask it for daytime vs nighttime.
I've been trying drivers on the rotation fields of a vector mapping node, based on the rotation of my sun, but not having much luck.

Related (but for position of a point lamp): http://blender.stackexchange.com/q/47175/599. For rotation of a sun lamp, I've done something like it in the .blend on this answer

I would do this by parenting an empty in line with the sun, then using the empty's coordinates as a vector in the node editor to get the sun's rotation.
First create an empty and parent it to the sun lamp.  The empty should be directly in line with the sun lamp, but not exactly on top of it.  To do this it helps to reset the sun's rotation (Alt+R) and put the empty somewhere directly underneath the lamp before parenting it, then re-position the lamp how you want it.

Next go to the node editor and add the following nodes.  The output on the right will be the desired gradient from facing sun's direction 1.0 to facing directly away from the sun 0.0.  The three Value nodes on the left are driven by the empty's X, Y, and Z positions respectively.

The position of the empty is converted to a vector using the Converter > Combine XYZ node, then normalized so that you don't have to worry about the distance from the lamp to the empty and scene units conversion to the node editor etc.  The desired output is created by taking the dot product of this value and the geometry's normals.
Note that since I am using the dot product, this output will be a quadratic gradient.  To get a linear gradient you will have to compute the vector similarity manually, or just use a color ramp or RGB curve node to create a satisfactory gradient.

For this to work, the sun lamp needs to be at world (0,0,0) right?

@ajwood  Yes.  But now that I think of it, you could quite easily set up the drivers to get the empty's position relative to the sun lamp if you need to move it around.


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Generated texture coordinates with shape key
I'm having difficulty using generated texture coordinates with shape keys.
Consider a surface like this (from Wikipedia):

I'm using a material that sets the color of the surface by its z-height (i.e. the z-component of the generated texture coordinates).
I'd like to animate the field with a shape key, however it seems that the generated texture coordinates are always derived from the basis mesh, rather than the result of applying the shape keys.
Is there a way to get the generated texture coordinates to update when the shape key weights change?

Try using the Object texture coordinate input instead of Generated. Works for me.


text:
Saving compositor File Output without rerendering
Is it possible to save a File Output node in the compositor without rerendering the entire scene?

Best solution I have so far is to add a dummy render layer with nothing in it.  Then, I can re-render just that layer, and the compositor will output all of the File Outputs.

I don't think there is a way to make the file output node save the files it is configured to save without rendering the scene.
A possible workaround for limited cases is to reroute the image input to a viewer node so that the image data can be viewed in the UV/Image editor. This allows the image data to be manually saved to a file.

Obviously for one frame of a simple multiple image file setup this is fairly easy, if you have configured a multilayerEXR then this will only allow saving one changed layer, one frame at a time. You could then open this file and replace the specific layer contents of the intended target file. The compositor could be used to combine the adjusted layer. Or you could use an empty scene that opens the existing files and composites the alterations into new files.

Since you don't want to rerender, I am guessing that your scene is already rendered, but complex. I think I may have an alternate solution for you.
I don't think that you can do what you want, but you can open a UV Image Editor and select Render Result from the list of images in the bottom panel.

Paul Gonet's image on BSE here.
From here, you can easily save.
Edit:
You can substitute a Viewer node in basically the same setup as previously described. In the UV Image Editor, select Viewer Node from the menu.

Also make sure that you have Backdrop checked at the bottom of the Node Editor.

From here, you should be able to connect any node to the Viewer node and have it show up in the UV Image Editor.

It's already rendered, and complex.  My issue is that I have multiple File Output nodes, which I'd like to save all in one shot.

@ajwood Understood. I have an alternate solution, but it may be a while before I can post (I have to go to bed). It's there, though.

@ajwood Luckily, I was able to answer your question more quickly. If it helped, please consider accepting it. It would help me greatly!

I would have thought 'do not overwrite' would achieve this, but nop.
[Or if you turned off the camera icon for 'render' but of course that is it's visibility in the render.]
The only solution I ever found was to have a second file that loads the images files from an Input Image node. Silly really. Scenes are the only way otherwise.
It seemed hinted here that you can force the Viewer node to "Save this Image" in the node inspectors Item panel, which might qualify, but again I just make a separate file for compositing typically.
It seems you are also able to duplicate Scenes and change the settings of things there. I think you can make an empty scene and then the 'render layers' input node in the compositor can be used to select different scenes and render them with a little button on the node.

you can use turbo tools to do this:
https://3dillusions.gumroad.com/l/turbo_tools


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Smoothing a baked f-curve
I have an f-curve baked from an audio file, but finding it too jittery for my usage:

It there a way to smooth the baked curve? I've looked through the modifiers, expecting to find a filter, but there doesn't seem to be one.

First, you can un-bake them:
(Install this as an add-on)
#########################################
# resamples baked f-curves to a new     #
# action + f-curve or a 3d bezier curve #
#########################################

bl_info = {
    "name": "unbake f-curve",
    "author": "liero",
    "version": (0, 4),
    "blender": (2, 6, 0),
    "location": "View3D > Properties Panel",
    "description": "Resample baked f-curve to a new Action / f-curve",
    "category": "Animation"}

import bpy

bpy.types.WindowManager.RGB = bpy.props.BoolProperty(name='Use RGB colors', default=True, description='Use RGB colors for f-curves')
bpy.types.WindowManager.scaleX = bpy.props.FloatProperty(name='X scale', min=.01, max=5, default=.1, description='X scale for 3d curve')
bpy.types.WindowManager.scaleY = bpy.props.FloatProperty(name='Y scale', min=.001, max=5, default=1, description='Z scale for 3d curve')
bpy.types.WindowManager.use_radius = bpy.props.BoolProperty(name='Use Radius', default=False, description='Use Radius / Height to visualize')

class Boton(bpy.types.Panel):
    bl_label = 'unBake selected fcurves'
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'TOOLS'

    def draw(self, context):
        wm = context.window_manager
        layout = self.layout
        box = layout.box()
        box.operator('curve.unbake_action')
        box.prop(wm, "RGB")
        box = layout.box()
        box.operator('curve.unbake_bezier')
        column = box.column(align=True)
        column.prop(wm, 'scaleX')
        column.prop(wm, 'scaleY')
        box.prop(wm, 'use_radius')

class UnBakeA(bpy.types.Operator):
    bl_idname = 'curve.unbake_action'
    bl_label = 'unBake to Action'
    bl_description = 'Resample baked f-curve to a new Action / f-curve'
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        return (context.object and context.object.animation_data)

    def execute(self, context):
        obj = bpy.context.object
        wm = bpy.context.window_manager
        pts = [(c.sampled_points, c.data_path, c.array_index) for c in obj.animation_data.action.fcurves if c.sampled_points and c.select]
        if pts:
            keys = bpy.data.actions.new(name='KEYS')
            for sam, dat, ind in pts:
                fcu = keys.fcurves.new(data_path=dat, index=ind)
                if wm.RGB: fcu.color_mode = 'AUTO_RGB'
                fcu.keyframe_points.add(len(sam))
                for i in range(len(sam)):
                    w = fcu.keyframe_points[i]
                    w.co = w.handle_left = w.handle_right = sam[i].co
            obj.animation_data.action = keys
        return{'FINISHED'}

class UnBakeB(bpy.types.Operator):
    bl_idname = 'curve.unbake_bezier'
    bl_label = 'unBake to 3D'
    bl_description = 'Resample baked f-curve to a 3d Bezier curve'
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        return (context.object and context.object.animation_data)

    def execute(self, context):
        obj = bpy.context.object
        wm = bpy.context.window_manager
        for c in obj.animation_data.action.fcurves:
            if c.sampled_points and c.select:
                sam = c.sampled_points
                cu = bpy.data.curves.new('path','CURVE')
                cu.dimensions = '3D'
                if wm.use_radius:
                    cu.fill_mode = 'FULL'
                    cu.bevel_resolution = 6
                    cu.resolution_u = 1
                    cu.bevel_depth = 1
                spline = cu.splines.new('BEZIER')
                spline.bezier_points.add(len(sam)-1)
                curva = bpy.data.objects.new('curve',cu)
                bpy.context.scene.objects.link(curva)
                for i in range(len(sam)):
                    w = spline.bezier_points[i]
                    y = wm.scaleY*sam[i].co[1]
                    if wm.use_radius:
                        w.radius = y
                        y = 0
                    coords = (wm.scaleX*sam[i].co[0],y,0)
                    w.co = w.handle_left = w.handle_right = coords

        return{'FINISHED'}

def register():
    bpy.utils.register_class(Boton)
    bpy.utils.register_class(UnBakeA)
    bpy.utils.register_class(UnBakeB)

def unregister():
    bpy.utils.unregister_class(Boton)
    bpy.utils.unregister_class(UnBakeA)
    bpy.utils.unregister_class(UnBakeB)

if __name__ == '__main__':
    register()

Script by liero (http://blenderartists.org/forum/showthread.php?221387-resample-baked-f-curve)
Select them all and hit Alt - 0. You may need to use it multiple times to get the desired effect. This is non-procedural, and any change you make are not easily undone (You have to use Undo).
Finally, if you wan't to, you can re-bake them.

This doesn't seem to do anything for me. I assumed it's because it's baked and doesn't have any point handles.

@ajwood found a solution...

How would you apply your f curve modifiers before you unbake the curve and smooth?


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Normal Map gives black render on half the surfaces
White walls, added a Normal Map.
Here is the file with the Normal Map:
https://drive.google.com/file/d/1lM8D70NWvQbNrYpkS4LUn7HvoDohJmcu/view?usp=sharing
Tried:

recalculate normals
invert GREEN channel
image is set as NON-COLOR
the object is FLAT SHADING

These are chunks from the viewport in Cycles:

This is in Eevee viewport:

And this is a render:

And this is a render with the RED channel inverted:

And this is the viewport in Cycles without NM:

And this is the face orientation:

I activated backface culling, so there's no way any of the faces shown are backflipped.
Aaaand... this is the shader:

Nothing fancy really- I really don't know where else to bang my head now.
I don't seem to be able to use Normal Maps in Blender, though I perfectly know how they work, and worked with them for many years, I always meet some kind of problem in Blender.
What is the secret?
Edit: under suggestion, tried to plug some vector nodes in the shader:

try giving it a texture coordinate node plugged into a mapping node set to UV and reset your UV maps

The UV were good, very simply unwrapped as they were, as this is a seamless texture. I added the nodes as you said, but it didn't work. Here is the setup, not sure it's correct: https://drive.google.com/file/d/1RIG_QwyWz4vZ8r-gFVDImY-0-0ur1DrJ/view?usp=sharing
Reset UV gave me a terrible, terrible setup.

The fact that Eevee does some type of automatic interpretation is kind of neat.

You need a Normal Map Node between the Image Texture and Principled Shader.

Now beware that this Strength parameter is in units at the scene scale, so most likely by default this is going to try to make it appear such that the highest point is jutted out by an entire meter.  It has to do this without affecting the geometry so it is likely to also give you some visual artifacts (such as pure black cracks) right out of the box.
I usually set it to .3 or lower before I even enter rendered view, and then adjust by eye.

Thank you! That saved me. Though for some reason a value of about 0.05-.0.1 is right for me, as this is a very subtle effect of wall plaster.


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Emissive shader does not change much in changes of orders of magnitudes
I'm trying to make some LED lamp but the EMISSIVE feature doesn't react as I expect.
I read on the Blender manual that the emission power is defined in Watts per Square Meter.
It doesn't really seem to work the right way.
From 0 to 1 it works well, but then, raising it to 10, it's not decuplicating the light, and even shooting it to 100000 won't really change much.
You can see in the images how the change from 1000 to 10 millions doesn't change anything in the final image.
For a test, I added an area light on top of the emissive model, and a 1 W light assigned to it makes faaaar more light than the emissive material.
You can see the difference in the final image.
What may be happening here?
Now, I may trick and just use the area lamp, but I want to know what is happening so to know how to work in the future.

Real world sizes. Emissive surfaces are exposed, nothing in between.
Actually, Eevee is not really lighting anything with the model, it just adds glow, a lot of it XD
Tried in a brand new scene, same problem: emissive power doesn't do anything past a certain threshold. It looks like the power is logarithmic.
You can download it here:
Also added the original file:

if you are in Eevee, the emission strength won't change anything unless you use a Light Probe > Irradiance Volume, so you'll need to add a light of use a light probe

I never experienced such issue. Have you tried in a simple, brand new file?

In the 4th img Use Nodes hasn't been clicked?

@HISEROD in the 4th image the selected object is the AREA LAMP, I don't need nodes to use that.

Could you add a blend file? https://blend-exchange.giantcowfilms.com/

a cycles solution would be something like a light falloff node combined with blackbody node, but I dont think either are supported in EEVEE.

Added new scene and original files.

@Timaroberts I don't want to use Eevee, Cycles is ok. But I think I can wait with this, if it's a bug, that they fix it.

The problem is the light clamping setting.

Set "Direct Light" to 0 to fix the power issue.
Setting the clamping to 1 means that any value brighter than 1 is clipped (or ignored), therefore it doesn't matter if the lights are set to an intensity of 1 or 1 million. Setting it to 0 means that the lights are un-clamped, therefore using their real values.
Read: What is Clamp Direct/Indirect?
Additionally, I would recommend setting the color management to filmic for more realistic tone mapping. Standard transform is usually used for video editing.

When using filmic you are using a much larger dynamic range, where the values can be much brighter than 1. Read: https://blender.stackexchange.com/questions/46825/render-with-a-wider-dynamic-range-in-cycles-to-produce-photorealistic-looking-im/46940#46940

Oh ghosh... I thought that parameter worked in a completely different way. Thank you very much for your help!!!!!


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Tutorial for facial animation toplogy?
I am trying to retopo a face and I would like to animate it, making smooth facial expression if possible.
I'm not a very experienced user but I do my best and try to learn as much as i can. Having a project helps me to get motivated and learn stuff.
I've seen a few tutorials for Retopology on YouTube, I know the basics (the process and avoiding Tri and Ngons) and making loops around the important features. I'd like it in a depth real course to follow along to be sure of what I'm doing, even if it's not a free course I'm fine.
thank you for your help !

Hi. Tutorial requests are off-topic, but if you can ask a specific question about an aspect of this that you are having trouble with, that would be fine.

When you are stuck on topology, always visit Pinterest for ideas. I always consult Pinterest for topology on faces, hands, ears, feet, legs, etc. There I always tons of topology ideas. If you have no account in Pinterest, you don't know what you're missing there. Pinterest is where you find plentiful pins & boards not only on topology, also on alpha brushes, textures, etc.

I'm voting to close this question as off-topic because this is a tutorial request (See: https://blender.meta.stackexchange.com/questions/1/what-questions-should-be-definitely-off-topic).


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Making a wavy plane
I've just started learning Blender for my games. I had been trying for the past 5 hours, to make curvy waves on plane.
I wanted the first picture to have the wave like as seen on the second.

I just created the plane below in a simple manner using loop cuts and a displacement modifier.
Final product:

Firstly, you need to create the geometry for what you want. To do this, I made a plane, scaled it up only along the x axis, and then pressed Ctrl+R to create loop cuts. I then pressed 20 on the keyboard for 2 cuts, and got the following result:

Then all we need to do is move each of these loops up or down. This could be done manuall, but I instead used a displacement modifier. Go into the modifiers tab on the right, and add a displacement modifier. Create a new texture for it, go into the textures tab, and change the type to wood. This will create a wavy pattern, but you will notice it is not smooth like the one you want.
Mine looked like the one below:

To make it smooth, I went back to the modifiers tab, and added a subdivison surface modifier. This makes it smoother, but you can still see all the individual faces. To fix this, I used the "Shade smooth option", and got the result I showed at the beginning.
I hope this helps!

thank you you saved my day it's perfect i follow your tutorial
this points is for future readers

when do you cut scroll the mouse  wheel to add more  cuts with equal distance
and displacement modifier called displace in the modifier tap

Here ya go: also, correct me if i'm wrong, but I think there's a randomization value you can mess with to make it less of a repeating pattern - https://docs.blender.org/manual/en/latest/modeling/modifiers/deform/wave.html


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Select every other edge (they share a common vertex)
Is it possible to select every other edge in this situation? (see image)
I searched the forums for an answer and read through them, but I couldn't find a similar situation. The Checker Deselect doesn't work, I guess because they all connect to a single vert.

Use  vertex select mode as indicated by the yellow arrow. Select the perimeter circle by any means including

Alt Click

Checker deselect every other one
Last select the center
If desired switch to edge select mode as indicated by the yellow arrow below
You may also consider saving your selection with vertex groups

Thank you. Works perfectly


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Messed up Topology (Shading?) due to the usage of the Knife Project Tool
Dear Blender Stack Exchange Community,
After trying to model a sword (after a concept art) I did run into some issues after using the Knife Project Tool. I am trying to add some Screws using the Extrude, Subdivide Command and Proportional Editing. However, after applying the Knife Project, weird Shadings started appearing.
I fixed the middle indent by connecting it to the rest of the geometry. The screw holes were done by keeping the produced geometry (Knife Project) selected and applying the transformation once, for all of them.
Now I did ask myself, whether I'd have to manually connect my screw holes to the rest of the mesh,or whether there is another, smarter way. Because by using this method I lose the accessibility of using efficient and clean loop cuts. I certainly do want to avoid ngons and poles as much as possible.
By the way, never mind my weird Subdivisions in the screw hole, I was going to fix it after solving this Problem.

This is very simplistic but when I cop shading problems/streaks after modifying a straight forward topology, I get into Edit mode and simply ease vertices in and out/above&below.  That often cures the shading problems or at least alleviates them.

Shading in this case will surely be corrupted as you have very nasty Ngons forming surface around the holes. Make those holes with lower amount of vertices, like 8, and use insetting to avoid changing curvature (and hence shading) on the sharp edges.

Yes.  Certain tools (booleans, knife, knife project) will do that.  If you want to use those tools, be prepared to retopo.  What's the question?

I have had the same problem with shading after using the knife / knife project tool. Unfortunately, I believe there is no sure-fire way to fix this.  One way that may work is to slightly bevel all the edges.  Another is to set the shading of the faces to flat, and leave the shading of the others at smooth.


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How to displace a curve without introducing artifacts at tight turns?
I'm displacing a curve using this geometry node setup:

The concave side of the tight turns end up with this artifact:

Is there better a technique for this kind of displacement?
Note this is a bit oversimplified from what I'm actually doing. I'm going to displace the curves in Z, for droopy electrical power lines.

try increasing the resolution, and lowering the length in the resample node.

Please note: This solution is more of a trick than a really solid and mathematical solution, but in most cases it leads to the goal.

...at least it's an interesting approach and can give you a good direction:

Draw your curve.

Then offset the curve points by a certain value, left/right or outside/inside.
...As expected, you get exactly the result you do NOT want.

At the same time, if you create a mesh from your original curve using Curve to Mesh, which is not quite as wide as your two outside curves, you will get a mesh in between, which looks a bit like a roadway

Now you can use Geometry Proximity to check if the outer curve points protrude into the inner area and you can remove them, leaving only the curve you are looking for

You can then edit these two curves with your desired profile. Keep in mind that this will cause the same problem again on the mesh itself, (but that's another topic, and as far as I know there is no funny trick with geometry nodes to solve it).

Here is a summary of the node group that leads to the described result (The inputs are marked green here):

Of course, with this solution the spacing of the curves is flexible, and in most cases the result should be without error (depending on the curve).

wow....impressive! +1

would you provide blend file?


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Is there a Frame node in Sverchok addon?
In the material and compositing node editor, frames are use to organize the node tree:

Sverchok doesn't seem to have frames:

Is it possible to add frames to Sverchok node trees?

ctrl+j will add selected nodes to frame


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Whiter white in cycles
I'm trying to make a material for arena ice in cycles. I'd like to end up somewhere like this:

and am having trouble getting it white enough.
Here's what I've got so far:

It is seems like I need to give if a lot of light to get up around the amount of white where it should be; so much light that it washes out my stones.
I've got a 50% mix shader with white diffuse and white glossy inputs. Is there a way to make my ice whiter?

Is there a good way to add the lighting settings without without adding the whole .blend file?

I've just 12 circles placed evenly above the scene at 75 strength emission.

your environment is gray I think, make your environment white or use a bright hdri

Also, make the ceiling light more spread apart. From the reflection, it looks like they are all clustered right on top of the rocks.

You can see from the screenshot I added that the lights should be plenty far apart (also, I changed them to spheres)

I tried making the environment white, but that has a similar effect to super-bright lights (everything gets washed out)

@ajwood You shouldn't need to make it that bright/white.. It's possible something else is going on. Could you upload a .blend with the lighting and ice setup? Or at least give a better idea how much light you needed to add before the ice got brighter?

More light is what you need. Try to ensure that your lamps are not all placed near the stones, so as to give a more even illumination.

Keep in mind that the environment is directly affecting the brightness/color of reflective objects, so set the world color to at least a brighter gray, though white is probably to much.
Imagine (or look at reference images) the kind of ambient light there is reflected from the roof/walls and floor of a large, brightly lit ice rink/arena. Sort of a soft grayish white. Here's what I used for the image above (I didn't use any method to come up with this value, I just eyeballed it):

Note that enabling AO will really brighten things up, but I'm not sure that's what you want. (you can also use the AO pass to get finer control using the compositor)
There are a couple more things you can do to make your ice material look nicer:

Use the Layer Weight node to make reflections more intense at sharp angles.
Bump map the glossy shades separately from the diffuse shader, which is acting more like the floor under the ice. If you really wanted to be realistic you could use multiple objects and a glass shader, but it is quite unnecessary as separate bump mapping looks fine.
Use two glossy shaders, one for sharp reflections and one for softer reflections.

Here's the node setup used for the ice material in the above image:

Note that it is possible that the bump mapping in your material has gone wrong in some way, causing the gray ice. But it's impossible to say without at least seeing the nodes.

You likely have your world properties set to gray. Change the setting shown below to white.

World > Surface > Color (with Cycles selected)


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Follow Path and Track To constraints together
I've got a camera with a follow path constraint:

Throughout the animation, I'd like to be able to make the camera point at something in my scene, rather than forward along the curve. For example, I'd like to make the camera look at Suzanne as it rounds the corner in the top right of the screenshot. This should be a smooth transition from pointing forward along the curve, to point at Suzanne, and back to forward along the curve.
I've tried parenting the camera to an empty, and tracking to the empty. The idea was that the empty would come along for the ride with the camera, but it could be moved off toward Suzanne as it gets close to the corner.

You could add a driver to the influence of the Track to constraint, whose value would be somehow related to the distance of the camera to the Suzanne.

Oh cool, I'll give that a try. I'm new to animating, so tricks like that don't come naturally to me yet.

With the following constraints the camera follows the path, with the influence of the Track To the camera can be directed to the target object. The influence can be keyframed by hovering and press I.

Demo blend

Hmmm... it's a little annoying that there's no -X, -Y or -Z in the "Up" dropdown :/

Any idea why my camera wouldn't rotate directly toward the target of the track to constraint as the influence is dialed up? It's taking a little arc on its way to the target (and still doesn't end up right-side-up for my needs, although it perhaps serves me right for wanting it to be upside-down :P).

@ajwood I rotated the camera in the linked files around 180°/Z to make it upside down. This looked better (no awkward moves).

authors: Валерий Чеклин


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Creating a scene with huge amount of geometry
I'm fascinated by the beautiful images Lee Griggs is able to create with Maya modelling and Arnold rendering.. e.g:

I'm attempting to reproduce his effect in Blender. My first stab at it is adding a big pile of cubes to the scene, displacing them according to an external texture, and adding a common material with colour based on object position. This massive number of objects seems to be too much for Blender to handle (or maybe I just need to get a better computer?).
Should it be possible to create such an image in Blender? If so, what tricks might one need to know about, in order to get around computational limitations? Or should I accept that some things just can't be done?

There definitely seems to be stuff hiding behind the taller towers.. that must be geometry, no?

... or are you suggesting that there would be some very rough geometry in the example image, but small variations would be texture maps?

The point of those images afaik was to demonstrate the new xgen system, which was made to handle those massive amounts on instanced geometry. Honestly I don't think blender could even come close to that if every instance is a separate object, but it might work if you were somehow able to join them into one mesh.

When my scene with thousands of gears started bogging down the 3D view someone on IRC suggested I switch to using Empties with a DupliGroup.  http://wiki.blender.org/index.php/Doc:2.6/Manual/Modeling/Objects/Duplication/DupliGroup

Blender does support instancing. If you could describe a specific problem? Perhaps the view port speed? You may need more ram (at least 8 GB is what I work with, with large mesh 16GB+) and a decent graphics card with lots of memory.

I s'pose this is when I should really get my CUDA drivers working.

I'll try Greg Zaal and Mutant Bob's suggestions first, and update accordingly

Related: http://blender.stackexchange.com/q/9206/599

Try using dupliverts:

It's not really that pretty, but this is just a demo.. Rendered in 6 minutes

Create a very subdivided plane, then delete only edges and face so that you are left with just vertices.
Add a cube and parent it to the plane.
Add a displace modifier on the plane, and setup a texture to use a displacement.
Enable dupliverts on the plane.

Amazing!:D I've never really understood dupliverts.. which came up in an answer yesterday

High vertex count definitely out performs high object count, whether it is one single mesh object or dupliverts - this answer compares  different ways of creating multiple cubes.


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Rendering a 3D volume
I'm playing around with ways to visualize an MRI image of my head. I've extracted my brain, so there are non-zero brain voxels in the center, and zeros to the edge of the image.
I'm imagining having a corner cut out of my brain to expose its interior voxels like this:
Additionally, I've also got voxel-wise statistical data that I'd like to use as a semi-transparent overlay on the anatomical.
Is this setup possible?

I think you can do this with BI, provided the format your voxel data is in is supported.

I've got it in 8-bit raw and can load it in BI.. I can't make it look like anything other than a smoke cloud though..

Hm.. I would think it would be possible with some nodes and procedural textures (I know it would be possible in cycles, if we could only get the voxel data..), but I don't know BI nodes very well and I didn't have much luck loading in some test voxel data.

I'm very excited about voxels coming soon to cycles! Thanks for trying :)

Here's my BI setup:
material:

textures:

The first texture is a nice dense whole brain object, almost making the voxel data appear like a surface. The second texture makes the voxel values affect reflection color, which is important for inside the object.
I used a simple boolean modified to cut away the corner chunk:

I'm using an MRI of a mouse in this question.. But I have an MRI of my brain that I've been playing a lot with :)

Awww that sucks! This was for research at a university, and they didn't mind giving me the image :) http://imgur.com/FF9U5Ql


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Setting Group Node Socket Type
Is there a way to add a socket of a specific type to group nodes? Currently, it seems that they default to grey scalar sockets, and I don't see any way to change their type.

Did you drag the wire from the BSDF/vector to the group output/input or vise-versa?

Ahhh no.. I've been adding sockets with the little plus button on the side panel.

Try dragging the wire to the empty circle node socket on the group node.

Related: http://blender.stackexchange.com/q/5459/599

You need to connect the temporary socket (red) to the values you want to make available from outside the group.

When tab out of the group you will have all of them available for wiring with the correct type (indicated bei their color).

Note that you can't edit them later you would need to recreate the group.

You're too fast!  I was just about to hit the "post answer" on mine!

@PGmath You should post alternative answers, we really to improve the answer ratio.

Answer ratio over the whole SE site, you mean?

@ajwood We need all criterias green  to promote and leave the beta status here: http://area51.stackexchange.com/proposals/40377/blender answer ratio is 1.4 required is 2.5

Oh cool - kind of a silly metric though.. so many experts here give perfect answers within minutes :)

As of blender 2.75, it is possible to remove sockets (using the cross X button in the right pane). Therefore it is possible to change the socket type by creating a new one and removing the old one, without the need to re-create it "from scratch" (it will sadly break existing connections on uses of the node, though).


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Accumulate field and for each loop
This is kind of a follow-up to Compute on all points in geometry nodes and How to calculate an attribute for each point which depends on every other point with the new for each zone.
I have two sets of points: a grid and a circle. I'd like to store an attribute on the point domain of the grid so that, for each grid point, the attribute would store the sum of all the inverted distance to each point of the circle.
I tried the following node tree but it does not work (I can disconnect the link between the capture node and the distance node and nothing changes).

Is the accumulate field the wrong approach here? How can I solve the issue (the goal here is to compute an electric potential that requires to sum 1/PM over the distribution, points P of the circle, for each point M of the grid)?

You're trying to access an attribute on a geometry that doesn't have it, see: What Does Capture Attribute Add to Geometry

For each point of the grid, evaluate "Attribute Statistic" for the entire circle, which sums reciprocals of distances from circle points to currently evaluated grid point:

Alternative image hosting:

Thanks (+1). That does the trick! And thanks for the linked answer in comments.

So, the problem seemed to be trying to measure distances between two arrays at the same time (one array for the grid, another for the points).
Since the grid is your target, I moved the foreach (in my case a repeat zone, since I don't have experimental Blender) to the circle instead and accumulated the potentials manually:

I tested the values by adding a viewer node reading from toto.
I also added a translation to the circle just to make sure it was working properly.
With a "for each" node, you wouldn't need the "sample", you could probably "capture" position from the "element" instead. Then you would not need "iterations" value, and also woudn't need the "index".
The file is attached here

Thanks for your time (+1). Your alternative seems to work as well.

Someone should benchmark and see if the foreach solution is faster, hopefully a lot faster, otherwise it's just a small QoL feature...

Probably faster, but even though it's not, it still saves lots of edit time, so..... What i'd love to see is a "loop while" node.

@DanielMöller Yes I think this is the only real code flow element that is missing, You can kind of emulate a while loop (repeat zones are slow, and that one is much slower) using this workaround: https://blender.stackexchange.com/q/320815/60486

@MarkusvonBroady, can we really do a foreach "element" using the repeat zone?

@DanielMöller I've done that plenty of times. You can for example pass "Index" to "Separate Geometry", with only the first index implicitly converting to FALSE boolean. So you can keep removing the first element, modifying it, and joining with already processed elements. BTW, I recently converted this to use the new for each zone and... It got 22 times slower... The algorithm wasn't ideal to showcase "for each" zone capability however...


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How do I translate a UV set of faces keeping the vertical or horizontal axis fixed?
How do I translate a UV set of faces keeping the vertical or horizontal axis fixed?
Tried with ⇧ Shift, ⎈ Ctrl, ⎇ Alt, no way: ⇧ Shift is for sharp movement, ⎈ Ctrl is for snap, both of them are not sharp enough, ⎇ Alt does nothing.

The keyboard-shortcut 'grammar'  is pretty consistent across the application, 3D View, UV editor, Node editor, etc. etc, It's worth getting at least the basic transform shortcuts : G Move, R Rotate, S Scale, and their constraints, under your belt.

Press G for the grab command and you can constrain movement by pressing either X or Y afterward.

Note that G+Axis works across all ofther editors in blender as well (like the graph editor, movie clip editor, etc)

Thank you! Didn't imagine that G was working also in the UV editor, as you can already manipulate with the bounding box!


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Where is the "default color" of a face, when a texture is applied?
In the first image you can see the materials displayed in the SOLID view.
T stands for a material that has a texture applied to it.
W, R, Y stand for 3 materials that have no texture applied to them and only use BASE COLOR.
Now, in the second image you can see that the materials render correctly in LOOK DEV mode.
They also work correctly when rendered.
Why, in the MODELING view they are colored weirdly?
Where do I find that color setting?
If I didn't need to use transparency, I wouldn't care, but unluckily I'm in need of that, and transparency is not allowed in the LOOK DEV mode.
If at least it was all grey.

Viewport display (for solid mode) and the material itself are controlled by two different settings
Take a look in MaterialProperties>ViewportDisplay on the object, it could have been mixed up

By the way, if on MaterialProperties>Surface the "Use Nodes" button is off, it will use Viewport Display by default

Oh gosh thank you! Didn't notice that section at all!


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Cannot apply scale to a multiuser
Why can't I apply scale to an object that has been instanced?
I mean: just apply it as the same to all the instances, no?
I forget to apply scale, then instanced the object 20 times, position it well and rotate it, and then I discover that it needs a small retouch that needs to be done in scale 1,1,1.

You cannot apply scale to multiuser because they can have different scales. Why don't you scale the object in edit mode?

Yes, as Carlo says.  If these are instanced they are all the same mesh.  Make a change to the mesh itself and it is done everywhere.

If you need to change a single one's mesh, duplicate it in place, and then delete the instanced version.

@Carlo I need to apply the scale because I need to add a modifier that works badly in different scale than 1,1,1.

@AllenSimpson that's not the point. The point is that in some cases it's needed to apply the 1,1,1 scale to one object or all the objects, so a feature in this direction would be useful.

What about the other object's scale? Doesn't it matter to your scopes? I mean, if you scaled the instance object's diffently, wouldn't this scale applying mess things up? You are not considering other object's scale in your argument.

Are your object's all with the same scale? You only rotate/repositioned them? Because if this is the case there's a simple solution to that. Please post a picture of the situation an add more info about your needs.

@Carlo well yes, in this case all the objects were only translated and rotated. They all have the same scale.

Clear the scale of all the objects and scale in edit mode
Object's transformations are a powerful tool that allow animators to give variance to their meshes without affecting the basemesh itself and take advantage of instancings greater performance.
Usually intanced objects have different rotation, position and scale, so applying one of these would only mess up your scene. If you don't trust me , you can try duplicating the object, apllying the scale and use the resulting mesh data as input for the instanced object.
If, as in your case, you didn't change the scale of your instanced objects, you can simply Clear the scale of all the instances with ALT+S and then scale one of the object in edit mode back to the previous value.


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Lightning issue - Constant light that doesn't enable the use of other lights
I'm following Blender Guru's tutorials, and I'm doing the last part that consists of lightning the chair. When I try to put the spotlight, I can't really see the difference because it seems to have a global light that I don't know how to shut down. In the final render, you can see that only the screws have a shadow, the chair remains with constant light in it. Could someone help me? Thanks! ^^

in what shader mode are you? Material or Rendered?

Any chance you forgot a Shader node and plugged your Image Texture directly into the Material Output?

@moonboots  In rendered.

@Christopher Bennett It is not. It is plugged in base color, in 'Principled BSDF'

Strange, it appears to be "un-shaded". And you say this is happening in the render as well as the viewport?

@Christopher Bennett It worked!!! ^^ You were right! The Image texture was connected with the Material Output indeed! I connected the surface in Material Output in the BSDF from Principled BSDF and it worked! Thanks a lot!!! ^^

That happens when you are not using a shader and plug a texture directly to the surface of the material.

.
Plugging a texture directly to the material output, the texture becomes  emission source.

Shaders define what happens to light rays on the surface of an object. Without a shader... well... there is no shading..
Use a shader and plug the texture as color.

Thank you @susu for your explanation! Super well detailed, it will certainly help others! :)


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Recover corrupt .blend file after power failure
I was working on my tutorial based project, when a surge in power made my computer shut down unexpectedly.
When I open my .blend file, it is not showing me anything. It's as if all the objects inside are no longer there, yet the file size has not changed, its still 4.35 MB.
I have tried accessing the autosave.blend file but it gives me an error code that reads "File format is not supported in file:
'C:\Users\my_Computer_name\AppData\Local\Temp\G_wagon_5020_autosave.blend'
I tried opening with another version of blender and it gave me an error that said 'missing DNA block'
Is there any possible way to recover the file to it's healthy state or is there any possible way I can transfer the objects data into another .blend file. Anyway to recover my file data?

Look for the .blend1 file of your project and open that one, that would be the previous to last file saved.

You could use photorec a data recovering tool to scan your harddisk! Cheers!

Certainly sounds like it ought to read that file.
Something you can try is opening a new file and File>Append>Navigate to your Blend file>Collections and select all the collections.
This should append all the objects with any data attached to them and they should still be in the collection hierarchy that you've used.


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Blender 2.9 Crashing upon Render using Animation Nodes. Image and Animation
Blender 2.9 Crashing upon Render using Animation Nodes. Image and Animation
I am using an RTX 2070 so I don't think it's my GPU and I should have plenty of memory. It is the first time trying to render a scene Utilizing the Animations Nodes ADDON but nothing else is different from past renders. Any insight is appreciated.

You might gain some insight by running Blender from the command-line (so you can see the error after it crashes) and find the .crash.txt file for more clues. Please post back with more info: What version of animation nodes are you using? What is the reported cause of the crash? Also, post a screenshot of your node graph. And post your .blend file.

Always use the last AN version, at this time it is animation_nodes_v2_2_windows_py37.zip
I also have crashes in 2.91, sometimes after 5 frames rendering, sometimes after 25 frames, so weird, I will check an older Blender version.....okay checking 2.83LTS...rendering for 40 frames now without crashing.
Looking good so far! Please try!
Freddy


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Multi camera for stereo
My question is this, say you have a scene and all the cameras are set up and all have key frames. Upon completion of the project, you decide to change the cameras out for stereo cameras to render out for 3d video, how would you go about transferring the key frames for position and rotation without the new second camera defaulting to the original key frames of the original camera.
For example would be you duplicating the original camera then shift it to the left, rename it camera_l and the original camera_r now when you start of the animation camera_l is going to drift back to camera_r original position and rotation, how do I stop this from happening yet keep the animation data so both cameras are in sync?

You could parent a second camera to the first one. If you duplicate the first one, select the second one and in the dropdown menu of the Dopesheet (Action Editor mode) click on the X button to unlink the action from the selection. Now the second camera will follow the first one. The only problem is that the gravity center is the first camera, but maybe it doesn't bother you.
Maybe the best solution is this one: Create an empty. Keep the empty selected and in the dropdown menu of the Dopesheet (Action Editor mode) select the animation that you've already created for your camera, the animation is assigned to the empty. Now select your camera and on the right of this same dropdown menu click on the X button to unlink the action from the selection. Now only the empty will move. Parent your camera to the empty. Create a second camera and same thing, parent it to the empty. Both the 2 cameras will follow the empty.
Does it answer?

i will give this a try and get back to you :)


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How to set Sun beams and mist in the compositor
I appear to be having some issues with setting up both Mist and Sun Beams for cycles in Blender 2.8. I'm attempting to to get a god ray/fake-volumetric effect from the window in my scenes. However, it doesn't appear that the rays or mist are being calculated correctly. It's supposed to look like a beam of light coming through the windows, now it just looks like a muddy mess!

Here is an example of what I want it to look like:

Here is the blend file as well if this helps any:
Blend File
I'm using an HDRI map to light the scene.
This is the node set-up I'm trying to go for:

I added my node set-up that I am trying to use. I want to avoid using volumetrics as much as possible to avoid increasing render times. I used the same set-up on another project and it worked great. I guess the only difference is I didn't use an HDRI set-up in that one.


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Call a function when new node link is created
Is there any way to trigger a function call when a node link is created with another node? The called function should be able to access both the input and output nodes of the link created.
It would be helpful if possible in the Materials node tree and not the Compositor node tree.

AFAIK such a hook doesn't exist. What is the bigger picture, what are you trying to accomplish?

Actually, I wanted to run a function when image texture node is updated (linked) with some other node. The function would check the link and change the values of the current image texture node

But to what purpose?

Like checking if input is Color type or not and then changing color space of image texture node automatically to non color data or color

This would be easier to implement as a cleanup pass after you've created the node tree. Just have a Python script go over all the connections and perform this cleanup.

Hey @AkashHamirwasia while Sybren might be right that you should do it at the end, there IS a way: The update-function of a node.

If you are writing your own nodes:
Yes! You can add an update-function wich can handle input-tests.
Your update-function will be called on every change of the node, so on linking/unlinking it will be called. Here is how:
class MyNode(bpy.types.Node):
    bl_idname='MyNode'
    bl_label ='MyNode'
    # your update function must only take self
    def update(self):
        # your code here
        for skt in self.inputs:
            if skt.links:
                print("Input socket {} is linked".format(skt.name))

If you are using existent nodes:
No, probably not. You simply can not overwrite the nodes own update-functions.
They seem to be like a read-only-property returning a function to you.
Setting them wont work, no matter what.

Thanks for the suggestion, I know that it is possible in Custom nodes but thought if it would be possible in default nodes. Probably not at this point in time.

@AkashHamirwasia Yeah, sorry. I tried a LOT of things, doing really really nasty hacks, but solely from within python, I was not able to change the behaviour. I guess you could fix something up with cpython, but that would probably be way more hassle than it's worth. But perhaps you'd like to write a driver for this instead? Should be possible... Well, best luck and stuff. :-)

@AkashHamirwasia Hey, I just thought: one could add a handler on redraw, and have it compare the nodetree.links to their previous state. (You could even just brute through it). Test if the from_socket.node is of type x, if the to_socket.node is of type y and then if from_socket.node.image is of the correct colourspace. If all but the last match, update the colorspace. As a redraw happens on each linking of sockets, it should work just like an updatehook...


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Arrow Flow Animation
I really need a water flow animation exactly like this.
I'm already using follow path, curve and array modifier but the result not as expectation.
Here's the exact sample I wanted:

My result the array is not following the curve path:

Your question is not detailed enough. What have you tried and what is wrong with what you tried?

ok @3pointedit i did add what i've tried

Array + Curve modifiers should make it work:

In Edit mode make sure that the curve direction is good, if not press W > Switch Direction.
Put the origin of the curve at its beginning point.
Put the arrow object at the same point.
Give your arrow an Array modifier with as many Count as you want and choose the Offset (distance between the arrows).
Give your arrow a Curve modifier, choose the Curve as Object, and choose the right Deformation Axis.
Move the arrow along the X or Y axis, depending on the orientation of the curve on the scene.

ok i did try so i have to move the axis thanks a lot :)

Yes setting the origin point (to be the same) for both objects is very important.


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Rotating each iteration of an Array Modifier
Is there a way to rotate each iteration of an Array Modifier?
For example, I've created the helices of a DNA molecule, and I'm trying to add the base pairs. I've got a cylinder with an array modifier.

Then, I thought I'd apply a simple deform to twist them 360 degrees, corresponding to one twist of the double helix. The problem I'm seeing is that the deform modifiers squishes the cylinders, rather than rotating them independently.

I just noticed that since I took the first screenshot, I've shrunk the double helix to just one spin.

If you want more detailed helixes, BioBlender addon 1.0 was released last month. It let's you load .pdf files from the protein database

If using a curve to generate the spiral, see: How can I duplicate a mesh along a curve?

I used a circle and a Screw Modifier, so I don't think that one would work for me. I might want to animate the helices straightening out into a ladder, so I might need rethink my approach..

How accurate are you trying to be? Are you just doing something that kind of looks like a twisted ladder, or do you need to generate a specific base pair sequence? If the latter, try 3D-Dart.

You can achieve that with the Array modifier alone.

Create an empty at the origin of your base pair and make sure it has the same xyz rotation.
Disable all offsets in the Array modifier.
Enable Object Offset and select the empty from the list.
Rotate the empty and move it up a little, so that it matches your helix.

The object offset uses the differences regarding location, rotation and scale to generate the array.

Another, older and in some aspects, more powerful way would be to animate the base pair rotating and moving up the helix and then turn on dupliframes in the Duplication panel of the object properties.
To get even spaces between the steps, you'd have to set the f-curve to linear interpolation.

Aha - I'd been trying something like this, but hadn't figured out to disable the constant offset.

Why would you consider the old way to be more powerful?

Because you can do custom movements, rotations, scaling, different spaces between Dupliframes. Array modifiers duplicate in a very regular fashion which is good for most cases. Btw, I said 'more powerful in some aspects', not 'more powerful per se'

Cool! I wasn't challenging the notion, just curious :)

Don't worry, I understood it right (:

Still works in Blender 2.93


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Can I set object viewport colour from cycles nodes?
I have a setup like this in a cycles material:

Is there a way to set the viewport colour using this ramp node?
So far, I just have a solid viewport color:

The material view still doesn't reflect the render:

Here's how they're coloured in the render:

I don't think you can do that. In Cycles, you can only use only one solid viewport color. This node setup would not show up, in the 3d solid view, but it can show in material view

A solid viewport colour is fine, I was just hoping I could set said colour from a node. Material view is fine though, thanks!

@Always4u Material view doesn't actually work either.. I'll update my question.

For complex materials, try to bake the material into textures, and then view it using material view

I bet you could script this somehow via python...

@Samoth I'm actually not so sure.. You may be right, but I want to use the same material across all the object.

@Always4u That might be a solution. Can you post as an answer?

Sadly you cannot set more than a single color per Material on an object in cycles, it is possible to get multiple colors as you showed in the LookDev (2.8) view mode.
the reason you do not see the random color array is because in cycles the random, just like the pointiness is only claculated in the render.

One sentence rarely makes a good answer. By the length of your answer alone, it should be a comment. You can put a little more effort into it, for example by explaining the technical reasons behind this behavior. This would rise your reputation, which makes commenting on any post available.


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How to create Quarter Cylinder
I am new to blender and couldn't find how I could make a quarter cylinder. I first tried starting with a cube and subdividing two sides. But this subdivided the two sides into two directions, not just one. Then I tried starting with a cylinder and deleting the 3/4 the vertices which did not result in something useful either. What is the standard way to go?

It would be useful if you showed an image or wrote a few steps as to how you went about deleting the vertices and how that didn't do what you want as this is what most people will suggest.

In edit mode I selected the vertices of the top half and bottom right fourth of the cylinder. Then I pressed x and hit delete vertices. The thing is here that the end's of the cylinder disappeared, only the curved side remained.

Related techniques at http://blender.stackexchange.com/q/19630/5486

Create a circle with number of vertices that is multiple of 4 (eg 8,12,16...), select all vertices, press E to extrude, press Alt+M to merge at center, delete unwanted vertices and extrude again to desired height.

@NoviceInDisguiseGraphics I think you couldn't write this in a shorter way, excellent even without images=)

Although there are many ways to do so, you CAN create a quarter cylinder from a cube:

Select the cube object, Go to Edit mode;
Ctrl + B to bevel the selected edge, roll the mouse wheel to adjust segements;
A + A to select all vertices, then W -> Remove Doubles.

Tip:
To ensure the maximum bevel extent on that edge, you can consider either one of the following ways:

After pressing Ctrl + B, you can see the available operations on the 3D View header (with shortcuts). So, you can then press M three times to switch bevel mode to Percent, then type 100 for a maximum Offset percent.

You can also do it after confirming the bevel operation, from either the lowerleft of the Tooblar (T) or a seperate popup menu(F6):

That is a really nice gif! Is there a special software for creating gifs like this? Just asking because I've seen quite a few here on blender.SE!

I personally use Ulead GIF Animator, which is not a freeware however. I'm looking for another FOSS one too. I remember @gandalf3 mentioned a cool one. Just forgot the name.

Thanks! BTW: In my version (as well as in the docs) it says the shortcut is [crtl]+[b]

Typo was fixed. :D

@flawr You might be interested in this meta post.

Moving the mouse past the maximum amount of bevel wraps around to zero bevel. Is there a way to be sure we're getting the max bevel?

The free one gandalf uses is LICEcap

@ajwood Please see the updated answer.

@LeonCheung #1 isn't in v2.71.. #2 does the trick for me though!

It seems the Linux PPA was abandoned a while back.. I haven't seen a new feature in months :(

Another way would be to use the Spin-Tool
Starting with a plane, here in top view notice the position of the 3D cursor:

Switch to right view and invoke the spin tool Alt-R

I personally like this one, since it can generate pie with any sector degree, not just a quarter. :)

This is another very nice solution! Can you tell me, how did you achieve that everything sticks right to the grid points?

@flawr the default setting is 90° so the gif seems to snap, the plane rotates around the 3D cursor.

In Edit Mode select 3/4 of the vertices of a Circle and delete the vertices X > Vertices.

Change the snapping mode to Vertex.
Extrude the end vertex along the Y axis, E then Y until it snaps to the other end of the curve.

Select all the vertices with A,A; then make a face with F
Without changing the selection press E then Z to extrude along the Z axis.

This is the final shape.

This is my usual method. Easiest way to do the selection is with circle select (C?) and paint the ones you don't want. Though there is an invert selection function too...

@StarWeaver I use border select, but any way that is most comfortable to you works.


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How to achieve an evenly distributed 90° turn?
I'm trying to bend "#Object 1" to something like "#Object 2" but with less triangle clutter and an equally distributed inner turn.
I tried the "Spin" tool on "#Object2" and a "Bevel" at the inner edge but that's not working very well as one can see in the image.

Any hint how I could achieve an evenly distributed 90° turn?

Easy way to do that is with spin selection around cursor. Put the cursor where the radius of the bend should be, select the edges which you want to extrude and hit Spin button in Tools panel. You can adjust the spin angle and number of segments in spin properties panel or by hitting F6 button right after spin operation.
Note that the spin operation is relative to the view angle.

That worked after some fiddling with the cursor, thanks a lot Denis!

You could use a path and the curve modifier for some real good results as shown below.
To do this use the start up file(box, camera, light).
In front view set the box X, Y, Z values as follows 3, 2, 5.
Next, create a 'path' from the tools section and have it aligned to the front view after-which you can shape it to a general 90 degree angle for the box to follow.
Next select the box and enter 'edit' mode and subdivide it at least 3 times. (you can play with even 1 subdivision if you want).
Go back to 'object' mode with the box still selected and put the 'curve' modifier on it and select the 'nurbspath' from the object dropdown and make sure the deformation axis is set to X.
Now use the 'grab' transform and move it along the X axis until it comes in contact with the 'path' and it should deform quite nicely along that path as show in my picture. (the picture shows a lot of the setting I just spoke about if you look closely)

Can you add a bit more info to your answer? Some newer blender users may still not know what to do after reading you answer.


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How can I model this twisted arrangement of cubes?
How can I model this handle?

I'm stuck on the cubes. I've tried an array modified + simple deform twist, but that's not quite right:

I think the cubes need to be arranged along the curve and only slightly skewed.

If you really want to follow your irregular reference closely, just manually create and align the cubes, it's only about 20 objects.

Particles or Manual Edit
Consider using a Particle System on a helix strip mesh created by Simple Deform Twist modifier.  Particles would be a group of objects which are cubes with random variation of shape.  Use Initial Orientation Normal with some small Random Value as depicted above.  No Array Modifier.
If you have just a few cubes you could
Press the [Convert] button to make duplicates real
and give each a rotation by hand.
The imperfect cubes are in a group and you can see a rotation of one in edit mode.
You may wish to state if you want to keep the varIations in cube shape and rotation.

The image above show 2 examples of orientation.
Full Coverage.  Placing a single particle on each face in the Helix Mesh.

[Emission Number] = (face count + 1). Goal 1 particle per face. Close to meeting goal. Result is 2 particles in same position on top. I have never investigated if this is declared a defect. (I have never investigated fully.) If you are going to [Convert make real] this problem may lessen, since you can delete. [Particles/Face=1].  A Hidden Portion of curve may be a bearable near solution.  You can see the two different colored particles on top.  When you increment and decrement Emission Number you can see this (interesting) situation.

I copied your particle settings - any idea why I can't get full coverage over my faces? https://i.sstatic.net/aSpPS.png  - One face gets a doubled object, and another is missing.

Please see edits.

Thanks. And I think you're right - I'll just make the particles real and delete the extra cube.


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Is there a way to compute vertex density?
I've got a mesh and am trying to figure out if there is a way to get a map of its vertex density. Ideally it would be something that I could put into a color ramp node and visualize. The goal is to get something to help understand vertex distribution in complex meshes. Areas with high vertex density would be bright, and low vertex density would be dark:

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

The Point Density texture calculates the distances from a set of points and can be set to either take those points from a Particle system or from mesh vertices. By using Object Vertices and setting the Object to itself, it will provide the density of the vertices of its own mesh. In the above example, the Vector Transform node is used to translate Object coordinates into World coordinates to drive the Point Density. This ensures that the Point Density is in the same location as the mesh.
Adjust the Radius to affect the influence of each vertex (higher values increase the distance at which each vertex will have an effect - effectively smoothing it out further), increase the Resolution if the results are 'blocky' (higher values will be slower to compute) and adjust the Multiply node to scale the result (here I divide by 1000 to bring it within the range 0.0 to 1.0 for the Emission node).
EDIT : Here's an example using the example from the original question. I've adjusted the settings to produce reasonable results without the circular artifacts mentioned by @LukeD. The artifacts are due to the Point Density also providing values between the vertices (rather than LukeD's approach that generates distinct vertex colors). The artifacts can be minimised by adjusting the Point Density properties - Radius, Interpolation, Resolution as shown :

Nice one as always! Sadly with example from OP I can't reproduce what I was able to make with Tissue and Weight Tools. Have a look here: https://imgur.com/UUY3qVM I've tried different values for Radius, Multiply and Color Ramp.

Thanks :-) For the point density you need to have the Radius much higher than the distance between the vertices - otherwise the influence of the vertex drops off too much before it gets near the next one and it goes dotty as in your image. Higher radius gives a blurrier result - it effective averages over the scale of the radius to smooth out the peaks. Really like the look of that addon - I’ll have to have a play with that. I suppose since that’s working on vertex weights/colors it doesn’t have a problem with the proximity falling off between the points.

I've tried with high Radius values but this produce circular shapes instead of keeping them rectangular after Color Ramp. I've played with Tissue since... Yesterday. I know it since a while but only from Tesselate and Dual Mesh options. Didn't have an idea that there is another section of it in Tools tab. Also check Curvature option - this one is pretty sweet.

Final result:
(enlarge to see vertex density)

Edit (your example):
After playing with Weight Tools I was able to achieve desired result even with ngons (more below), also Color Ramp in this example is set to Constant color interpolation.

Overview:
You can achieve such effect quite easily with newly built in add-on - Tissue.
As an example I've used Suzanne with Sculpted regions (Dynotopo).

Note: I've not tested it much but it seems that it is working best
  with triangles and not so good with ngons (colors are triangulated).
  Quads are working pretty ok too.

Steps:

Turn on Tissue add-on.
Select your mesh and go to Tools shelf and at the bottom there is Tissue Tools section (beware, Tissue add-on have also section in Create tab).
Select Area. This will create Vertex Group.

Now you are automatically switched to Weight Paint Mode.
Under Weight Tools section choose Levels and tweak them to have desired result.
Unfortunately there is no good/bad values here, you'll need to play with it a bit. Also sometimes other tools from this section could help, like Smooth, Clean and maybe some others. It depends what mesh you have.

Now back to Tissue Tools section and select Vertex Color from: > Vertex Group. This will create... Well Vertex Colors from Weight Painted Vertex Group.

Last thing is to make material with Attribute node, type there Vertex Colors name - in this case 'faces_area_value' and use it as input for Color Ramp, or Mix Shader Factor or anything else.


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How to create edges between two lists of vertices in Sverchok
I've got two sets of vertices in Sverchok:

I'm trying to draw edges between each corresponding vertex. I came up with this, but it seems overly complicated:

Are there any Sverchok nodes to simplify this operation?

List split
You can use one node with the List Split node. You'll avoid the repetition of the double Range Int node.

It's just a slightly different variation from your implementation. Apart from building a node that makes all at once, I can't think of a way to simplify it further.

try UV-connect node simply
join two objects by vertices into input sockets for uvconnect
http://nikitron.cc.ua/sverch/html/nodes/modifier_make/uv_connect.html

try many objects also, different parameters


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Rendering unconnected edges
I have a 2D base image on which I'd like to overlay a set of edges (several thousand), where each edge has a value determining its color.
For example:

My plan is to add each edge as a separate object with a custom property; then a single material across all edges can use the custom property to determine color.
The bit I'm having trouble with is actually getting edges to render. I was hoping that a wireframe modifier would give the edges enough geometry to be visible to the camera, however edges without associated faces don't seem to survive the modifier.
Is there a good way to get these edges to render?

I've found that having several thousand separate objects is much slower than having one object of several thousand edges. You could use vertex colors to give the edges a sort of ID, as a replacement for object IDs. You can render edges in BI, but not in cycles - which are you using?

I tried both.. freestyle edge rendering had the same trouble as my wireframe modifier though

@GregZaal: It seems that even vertex colors are tied to the existence of faces! I suppose Blender simply isn't designed for rendering edges.. perhaps I should look for a different tool?

Might it be possible to use something like hair particles instead?

Those lines kinda look like hair, eh? I'm pretty inexperienced with hair, so I'll have to do a bit of research before I weigh in

Cycles
I don't know of any way to render edges like this natively in cycles, however the screw modifier can add geometry to edges:

It's a bit of hack, but I don't know of any faster way to add faces to edges using modifiers (it's not actually that bad, in most other cases using the screw modifier you would probably use only edges anyway).
Blender Internal
You can render edges using a Wire material:

Opengl
Of course, the viewport can render edges, however you are pretty limited in terms of controlling the color..

This patch may help though.

My problem with the BI solution is that I can't use vertex paint to control the edge color.. The cycles solution doesn't look very good for my data.. and the Opengl again doesn't give enough color flexibility

Both the skin and wireframe modifiers add renderable thickness to edges.

@PGmath The skin modifier is quite heavy (probably no good for>1000 edges), and the wireframe modifier doesn't work on edges without faces (not sure why though).

You can try the skin modifier for semi-okay results.
for better results,
try rendering curves with vector points at the start and end instead of edges (v key in edit mode) .
under curve properties, set the fill to "none" and turn up the bevel/bevel resolution - this will create a "pipe"
Edit: more detailed instructions here as requested by CharlesL: (right click image, view image to zoom)

Could you detail the workflow a little more? It will make the answer more accessible to beginner users.

CharlesL: see above.

@user1562431 Please try to avoid putting text into images without also explaining with actual text. Search engines can't read text in images..

affirmative. Images were for clarifying earlier text. Will keep formatting in mind for next response.


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Is there a way to get rid of this square artifact coming from lens distortion?
I've got a noisy render that I'd like to composite with slight lens distortion (Fit=True, Distort=0.03, Dispersion=0.001):

I'm noticing a repeating pattern of square artifacts in the output of the lens distortion node. Here is zoomed in on the lens-distorted image:

Is there a way to improve the quality of this lens distortion?

This is not a bug.  It is simply how the the image manipulation algorithm works.  This must be fairly common since Corel seems to use a similar algorithm in Paint Shop Pro:

It's worth noting that the square pattern only appears close to the center... outside the center it becomes more like a concentric circular pattern radiating out.
The reason for these artifacts is that you are distorting an image made up of square pixels.  Ideally, this is what would happen to the pixel array:

However, you obviously cannot distort the pixels themselves and still have a proper 2D array that can be read by typical image software. So you must do some sort of combination of deleting and averaging of pixels.  Because that can't be done on a pixel level (there are no fractions of pixels), the image must be subdivided into sections in order to deal with each subset.  In the center, it makes sense to do this in square sections (since the distortion is minimal), but on the edges it should be concentric sections (since the distortion is circular in nature).
A uniformly noisy image (with large, flat, mono-chromatic planes) is pretty much the worst case scenario for this algorithm because of the contrast between individual pixels on sections that would otherwise have little variation.  You probably wouldn't even notice the artifacts on a smooth image unless you were really pixel-peeping. Here's the same distortion applied to an image rendered at 500 samples:

In short, this is to be expected.  The only way I know to reduce the effect is to apply noise reduction before distortion in your Composite node chain, or start with a less noisy image.  Essentially, the lower the contrast between individual pixels, the less visible the artifacts will be.

Are you saving and loading your render between steps?
This looks more like a JPEG blocking artifact than any kind of interpolation / rounding bug, but it only applies if you're saving the output from rendering the noisy image and reloading it to apply the lens distortion.
See https://photo.stackexchange.com/a/29646 for an example, the last sample image with visual block structure. If this is the case, saving as PNG or TGA or nearly anything other than JPG will fix the squares, since it's the JPG format itself that's adding them.


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How do I export to cinema 4d?
I have a render that looks great in Blender, but when transfered using any method it looks terrible in Cinema 4D. Can anyone point me in the right direction?
All I need is my textures to somewhat resemble what I have in blender. I can include for info if needed.

Are you using raster (png, jpg,...) textures or procedural textures using the shader editor ? Hint : You can't export procedural textures

i purchased a gig off of fiverr and he modeled it for me in blender... some are png textures but most are most are internal textures (basic colors). is there a way i can bake textures for my object so i can link them up in c4d? theres a lot... 97 i think.

C4D (even Cycles4D) and Blender have very different shading workflows... I don't remember offhand how C4D supports gltf, but otherwise you will have to reproduce any blender procedural materials with C4D materials.

https://blender.stackexchange.com/questions/57531/fbx-export-why-there-are-no-materials-or-textures

In order to have your materials in C4D, you need to create a UV map for your objects and bake your materials to get Texture images (Normal maps, color map, specular maps, AO Maps, and so) and then you just need to adjust the parameters inside C4D


text:
The liquid does not get into the pipe
The liquid does not get into the pipe.

I've tried
Is planar off , on
Flip Normals and is planar off

we could help you best if you would provide your blend file ...https://blend-exchange.giantcowfilms.com/.   There are a lot of reasons why this happens e.g. a face in the way which we cannot see in your picture or multiple other reasons....

My suspicion would be that your Domain Resolution is set too low. It needs to be high enough to allow simulation ‘cells’ to be small enough to fit within your pipe.

there is

@Chris i shared

Make sure you have applied the scale to your domain. Blender uses real world numbers for it's sims and it thinks your domain is much smaller than it is.

ok, make these changes:

assure that your pipe is converted to mesh
add a solidify modifier to the pipe with 0.2 thickness and apply it
set surface thickness 0.2 in the fluid tab of the effector
remove velocity of inflow (because i am not sure whether it is too fast, maybe some other parameters have to be changed to make this work), so just set velocity to 0

bake again -> test

i'll try after answer you thx