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Make Volumes only visible when light overlapps it
I wanted to know if there is a way of telling blender that volume objects should only show the volume, the fog and stuff when it is overlapping with a light source. I was trying to replicate the Youtube tutorials on how to make Volumetric light, but it does not really do the trick for me. I don't want to have the fog EVERYWHERE inside the cube, but only when where for an example a light cone is shining.

Answer: Okay, thanks to the comments I was capable to find the problem, it was the emission property of the principled volume in the shading editor for the volume material that is set on the volume cube. I just set it to 0, and it gives me the desired effect now.

What are your settings in Light Paths > Max Bounces > Volume? And do you only have spotlights in the scene which should show the fog or is there a sunlight or other environment lighting?

@GordonBrinkmann What are your recommended settings to get it to work how I want it? There is only one spotlight, one cube with a volume material. I don't know where the light paths setting is you mentioned.

In the Render Properties you will find Light Paths > Max Bounces and then Volume. If the bounces value for Volume is larger than 0, light will be scattered inside the cube and therefore also be visible outside of the spotlight's cone. Values ≥ 1 will be more realistic for a room filled with fog, but will also take more time to render and produce your undesired fog "everywhere".

@GordonBrinkmann Thank you for the information. However, I just tried both 0 and 1 and in both cases the fog is everywhere where the volume cube is. To say, the one with the volume material.

That cannot be actually with bounces 0 if there is no other light source. Because the light from the spot won't reach the fog in the rest of the cube. You're sure there is nothing else? When you turn off the spotlight it's absolutely black? No light coming from the world?

@GordonBrinkmann I added two pictures to the main post, so you can see it for yourself.

The last image is without any light source? Then the fog should be black, not glowing... would you mind showing your fog material? Looks like you've got some emission in the fog itself.

@GordonBrinkmann ... that was actually the solution. Thank you allot for pointing that out for me. The emission property of the principled volume was set on 0.1 or something. I just set it to 0 And now it works. The volume is only there where the light shines. Thank you allot. You are a great help.

If you change the color of the Principled Volume almost to black and the Absorption Color to full white I think you will get that effect.

That's not how it works. I mean, maybe this is the desired result, but simply try two different settings in the Principled Volume shader: 1: Color to dark grey like V = 0.01, Density to 1 and Absorption Color to full white at V = 1. Compare it to 2: Color full white at V = 1, Density to 0.01, Absorption Color black, V = 0. The result will look exactly the same. With color white and density 0.01 you can also set the absorption to white, it still looks the same. What makes the fog visible is if you also have a sun or environment light or the Light Paths Volume bounces > 0.

Just for a short explanation: all fog which is visible in the air comes from scattered light, whereas the Absorption Color manipulates (as the name suggests) the light absorption. Light that gets absorbed doesn't show up in the camera as visible fog in the air. That's why in your solution you have to leave the Color at dark grey and cannot turn it all the way down to black. Black means no scattering, so no visible fog, no matter which Absorption Color you choose.

Thanks for the explanation.

You could create a cone, give it volumetrics, and give it the exact same shape as the light spot cone:

Another trick would be to use a cone with Emission and Transparent node and a Layer Weight node as factor, see here.

That's a good idea! And if you want real volumetrics with objects throwing shadows in the fog definitely to be preferred over the trick you've linked to. Then combine the cone with Copy Location and Copy Rotation constraints targeting the spotlight and you can even reposition the light easily.

or simply parent the one to the other?

Haha, of course :) I just used constraints because I already had the light in a certain position and angle so parenting at this constellation made no sense :D The only thing with this method which has to be kept in mind: if you've set the spotlight to a soft edge, this gets a sharp outline from the cone if you set the volume bounces to a value greater than 0.


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IK Rig is broken on one half
A very common IK rig problem I always get is that on one half of the rig ( in terms of circular movement of the empty ) the rig completely glitches and behaves broken. It is flipping around and does not correctly behave at all like on the " right " half
I have recorded a little video showing what I mean:
https://www.youtube.com/watch?v=8X0-qnsgPu0
For Additional clarification. This ALWAYS Happens to me in some way or form. I have never had an IK Rig that does not flip.
Edit: I have added a pole target which helps the Rig rotate without the glitching. But it is still flipping around.
https://www.youtube.com/watch?v=SoukPw-UfeY
Can you please help me out with that as well?
Edit2: I HAVE FOUND THE SOLUTION!
I have added a " Child of " Constraint to the pole bone and set the father to the first bone in the Chain. Moving the control empty now results in the Whole rig animating Like I want it to without glitching or flipping.

If you use Pose mode to inspect each bone, do you have any "Bone Constraints" like Limit Rotation?   Such constraints could cause this.

@james_t Thank you for the Idea, but that is not the Case. The only constraint is the IK constraint on the last bone.

If your IK bone has no Pole Target bone, at some points it doesn't know how it is supposed to bend, I guess it's your problem here

@moonboots Thank you for the Tip, that fixed glitching behavior, but it still flips when meeting the diagonal direction of the pole bone. I have added another Video in the Main question description showing what I mean.

there's still an ambiguity on how it is supposed to bend towards the pole target, you need to move the pole target so that it always makes the knee bend in the direction you want

@moonboots How exactly and with which Constraints do I do so? Do you have a Step by Step list or a video showing this?

you just need to animate the pole target bone, please share your file

@moonboots Never mind, I actually found the solution myself. I have added a " Child of " Constraint to the pole bone and set the father to the first bone in the Chain. Moving the control empty now results in the Whole rig animating Like I want it to without glitching or flipping. Thank you for pointing me into the right direction with the pole target.

source: Stack Exchange

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

sort: votes


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Create a arrow from cylinder and cone in Blender 2.8 python API
I know this question is redundant and asked multiple times. Though there are solutions available for the older versions of python API, for 2.80 I couldn't find out.
I want to create an arrow using primitive_cylinder_add and primitive_cone_add. As I want to use many arrows, I want them to act as a single object, so that I can translate and rotate as a whole. Following are my sketch, not a working code. I am wondering, how to merge them?
def draw_arrow():
   # object length and radius will be fed as argument
   bpy.ops.mesh.primitive_cylinder_add(radius=0.1)  # location will be set
   bpy.ops.mesh.primitive_cone_add(radius=0.2)

   **code to merge them as a single object**
   return bpy.context.active_object  # return arrow

def main():

   arrow=draw_arrow()
   ob = bpy.context.object

   # draw, translate, rotate multiple times as needed
   n=5
   for ix in range(-n, n, 2):
       copy = ob.copy()
       copy.data = ob.data.copy()
       copy.location.x = ix
       copy.location.y = jx
       copy.location.z = kx
       copy.rotation_euler[1] = theta
       copy.rotation_euler[2] = phi
       bpy.context.collection.objects.link(copy)

   bpy.context.scene.objects.update()

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


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Cannot scale or rotate geometry in object mode
I'm a Blender newbie and I've got a scene with lots of geometry in it, but now I can't scale or rotate anything. This also applies to new primitives. I've searched the web and this forum, but the only answer I've been able to find is the Manipulate Center Points button is enabled. But I'm using 2.8, and can't even find that button. All transforms are unlocked. Any ideas would be greatly appreciated!

Did you accidentally enable snapping option? Or you lock the object in outliner?

No, snapping is off. And the all the objects are unlocked in the Outliner. This problem also applied to new geometry that was created - no ability to scale or rotate but translate was possible. I went around the problem by opening an earlier version of the file, but that problem is still a mystery.


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Why does joining meshes result in a joined mesh with (previously) non-actively selected meshes being transparent?
I am currently working on a character model / rig and I want to join some meshes together to a single object (not parented).
However, every time I try joining any mesh, all geometry except that of the mesh which was actively selected (bright orange outline) before joining becomes transparent.
Shown below is the character model with non-joined meshes and the same two meshes joined to a single one. In this example, the eye-mesh was actively selected and the body secondarily (i.e. dark orange outline). The result would be inverted if the body was actively selected (i.e. eyes transparent, body normal).
Anybody have a clue what the cause could be?
The shaders all transfer correctly, nothing is changed in the viewport visibility section, flipping or recalculating normals doesn't help... I really have no idea at this point.

As a possible cause suggested was the "Blend Mode" of the material being set to "Alpha Hashed", this isn't the case either. The Materials are all assigned to the correct meshes and both remain "Opaque". In the images below I selected a face of the previously separated meshes respectively and took a screenshot of the material tab:

This transparent behavior looks to me like material's blending mode: alpha hashed is set. Can you check that the material which is assigned to body in the joined object is actually the skin material and not an eye material?

@J.Doe I just updated the post: unfortunately the blend mode isn't the reason either. "Default" is the correct Material for the eyes, "Edited_Body" a variation of Default for the Body (with heightened contrast in the diffuse and subsurface scattering).

@J.Doe So I just did some further investigating and noticed that the UV maps of the non-active mesh are gone (i.e. the body in this case) --> that's most likely the cause. Any Idea how to keep the correct UV maps when joining two meshes?

I figured it out!
The issue:
The UV maps didn't get combined on join because they did not have the same name. This resulted in all but the first UV map becoming inactive and all but the actively selected mesh, while having the correct material assigned, using that first UV map. That then resulted in the assigned materials then not being mapped properly.
Solution:
Before joining the meshes, rename all UV maps to the same name. This can be done in "Object Data Properties" (the green triangle above the material tab) > "UV Maps" --> Double-click on names to rename. Then simply join as usual. The UV maps will now be combined correctly and the corrected parts of the resulting mesh will have the correct materials assigned to them properly.


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How can I remove the instances from the cap and ends of a path with an array
I have been using this tutorial here: https://www.youtube.com/watch?v=tA462u7iHW4
However, when I set start and end caps in the array modifier ( just a cube ) it looks like this.

I don't want to have the sphere instances where the cube caps are. How can I deactivate / remove them?
Merging the plane that gets array'ed does this:

Hello ! I think this would be trivial with a geometry nodes setup. Have you explored it or do you need to use this specific workflow ? (Older version, etc)

@Gorgious I never worked with geometry nodes before, but if it works, I would be happy to learn that solution. Do you know if the specific workflow has a solution as well?

ok, instead of a plane, just use one vertex, then it works. So select your plane, edit mode -> M -> merge at center should solve your problem

@chris That ends up removing the spheres as well and the caps still have the spheres. I updated the main post with a second image.

then pls provide your blend file, so we can check it out. thx

@Chris I added the blend file to the main post

ok, this isn't possible with array + curve modifier (AFAIK) but with this node setup, you can easily make it with geometry nodes:

result:

Thank you for your time investment and your answer, you are a great help. On which object do I have to bind the node setup on? And do I still need the modifiers, or can I remove them?

Also, can you please provide the blend file you made? I tried replicating the nodes, but my end result looks very wrong.


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Blender renders the black background in a very... strange way?
I literally never seen this before.

Why does this happen? Does someone know a fix?
Blendfile:

Picture your self reading this Question as it was asked by somebody else. How big could be a chance to answer this Q  and be right. Result like this can be achieved many ways and we don't know nothing about your setup, app version, etc ... please share your simplified blend just with a single object if issue persist. blend-exchange.com

@vklidu I added the blend file

You have a ridiculously high light Power setting in the file that you uploaded (250000 w). What setting are you using in the image that you posted?

The weird appearance comes from the ridiculously high Power of the light in combination with the Denoise option. I guess Blender calculates some stray light particles reflected from the object all over the image and the Denoise makes some muddy overall low brightness of it. I draw this conclusion from the fact that this effect becomes less intense when you lower the Power of the light and even disappears completely when you disable denoising or make the object invisible so that there is no more surface getting hit by light.

Also removing the multires modifier removes the problem in this case.

If your Q is referring to the brighter streaks in black around objects, than Gordon's comment sounds to me right ... for sure if your screen was rendered with black plane under those "white" objects (blend you shared, doesn't contain this plane so I don't have the issue seen in your screen.


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Rendering an animation as image sequence only renders the first image
I have set the settings to render my animation as an image sequence, Sequencer is activated in the post-processing area as seen in the picture below.
However, when I want to render it and go to render animation, and not render image, it always just renders the first frame and stops there...
Does anyone know why this happens and how to fix this? To render all the frames as PNGs?
Here is the blend file:

@RobinBetts Compositing and Sequencer are usually both enabled by default. It does not matter if there is nothing in the sequencer pipeline, in this case it will simply render the compositor output/render layers.

Turn the Compression right down to 0% on the Output format panel. (I think the default is 15%.) You have it set to 100% at the moment which is drastically slowing down the render output!

i am not sure whether this is the reason or whether you have an add-on installed or it might be the OS - but if i open your file, the denoiser setting is empty: [1]: https://i.sstatic.net/4Qe28.png if i choose a denoiser, the rendering works for me

@JohnEason Thank you, that fixed the problem! I have set it to 100 first because I want to have absolutely perfect renders without compression loss of quality.

@Chris I have chosen OptiX for the denoiser, I got a RTX 3060 12GB VRAM that works well with the OptiX denoiser. Which Denoiser did you choose?

i am on a mac and the only choice i had was openimagedenoiser

@user140193 With a 4kx4k file, each png is over 130Meg uncompressed, so it's not surprising that it takes for ever to compress each frame 100%, even with just a plane in the scene.  Turn it down to the default 15% and each frame is then just under 20Meg when saved and renders and saves quickly.

Also worth reading the answer here: https://blender.stackexchange.com/questions/69655/what-does-the-compression-setting-do-to-a-png

Turn the Compression right down to 0% on the Output format panel. (I think the default is 15%.) You have it set to 100% at the moment which is drastically slowing down the render output!


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Position a Bones head in editmode in global position
I want to absolutely perfectly position my Bone's head position, fitting to the Mesh vertex position. I just wanted to copy and paste the vertex position to the bone's head position.
Problem is, the bones have completely different positions in edit mode than the vertexes in edit mode.
Can I somehow change the positioning of the bones or maybe the whole armature to global position?
Or is there another way of perfectly positioning a bones head to the position of a vertex?
I found a solution for everyone seeking for an answer.
Set the 3D cursor to the selected vertex and move the bone head to the 3D cursor via spacebar search functions!
like:
selection to cursor and
cursor to selection

Using 3D cursor for this is a quite classical way, but there is an easier method, using snapping:

Using 3D cursor is useful, though. For example, when you need to snap at the center of a circular shape.

While this also works, I have noticed that the position of the bone ends up being a few millimeters off the vertices, which makes it unusable for me as I really want it to be perfect. The cursor selection and selection to cursor method takes a bit more time, but gives me more precision. So, thank you for your contribution anyway.

Make sure that you have enabled snap to vertex, (face by default)


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How to prevent texture stretching?

here the file with the problem.
bc how to prevent texture stretch when the texture is going up the wall.

Hard to tell without knowing your topology and uv map, but I guess your faces are far from being square?

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

I guess you can't, unless you rotate the empty that controls the movement of the image. One thing you could do though is unwrapping the object Plane, and use the UV output of the coordinate, then you can control the image texture projection with the UV Warp modifier, or just the Mapping location values?


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Problem with ShrinkWrapping
hey quick question why is it that when i use shrinkwrap (or use any Deform Modifier) on instanced object the number of overall geometry doubles ?
I use Blender 3.0
Here is a blend file
btw thx KickAir8p
for the help
if you open the file and shrinkwrap the instanced mesh yourself and the geometry count dosen't change pls tell me Thx
here are before and after photos of putting Any Deform modifier on instenced mesh

i heard that in order to deform instanced mesh it has to make it real is that true ?

Hi, congrats on your first question here!  That shouldn't be happening, and I've been unable to duplicate the problem.  A couple of screenshots (before & after) showing the problem and surrounding settings might be helpful.  Also, it's sometimes a good idea to post your blend file, or a truncated version of it that has the problem.  Not sure about this time, but just so you know, the Blender StackExchange has its own service to share blend files:  https://blend-exchange.com/help

Sorry, on first reading I missed that you were doing this on an instanced object.  Yes, it's happening when I try it.  Wouldn't surprise me if it was normal behavior, but I don't know.  Hopefully someone else can be more helpful.


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How to sort object exactly like Blender sorts object "Alphabetically"?
I have the sorting like this:
objects= col.all_objects[:]
objects.sort(key=lambda x: x.name.upper(), reverse=False)

I've used .upper() because blender's sort is case-insensitive. But in the same time non-Latin sorting is case-sensitive, so I get wrong sorting with .upper() in non-Latin object names:

Console output:

Other nasty thing that Blender uses case-sensitive when sorts name.00x things:

How it is supposed to sort objects to match them with Blender's internal sorting?

I think the relevant function is outliner_sort. Also see BLI_strcasecmp_natural.

How Can I use it in Python?

I don't know if there's any way other than porting the code.

This is the solution from me. Instead of thinking about nasty sorting in Blender, just make unified names:
blocks = col.all_objects[:]
    for block in blocks:
        block.name = block.name.title()

And then sort.


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UV Unwrap and Normal Baking Issues
OK, So Im working on retopology for a model. I did a smart UV unwrap on the model, decided i didnt like the way it unwrapped. I deleted the UVMap that was created, added some seams, and unwrapped again. I baked my normals from the HP mesh to the LP UVs... The baking worked perfectly as when I import into a game engine, I dont have ANY issues with the normal maps. The problem lies with when i render in blender. Below are two images, The first from the mesh that was freshly exported to FBX and imported into Unity.

The second image is Blender 2.80.75 showing a few highlighted faces so you can see what is going on.

Im not sure if this is a bug, or i'm totally missing something. Any advice would be GREATLY appreciated. but as you can see the arrow should be pointing to horizontal lines... the normal bake next to the blender image even shows that. Ive tried to disconnect and reconnect, force the node editor to use the one and only UVMap from the unwrap. Ive tried deleting the UVMap and unwrapping again. Im just hoping maybe someone can point me in the right direction. Thanks for your help!
https://i.sstatic.net/JcVKk.jpg

Your screenshots are very low resolution, so its hard to see whats going on, can you add larger ones?

@Sazerac ya, I will tonight, sorry about that.

@Sazerac I added an imgur link (https://imgur.com/a/xjpgLQ0) notice that in the UV Editor window, the faces that are highlighted should translate into horizontal lines, rather than the diagonal lines that are shown at the arrow.

Have you added a UV map to the Vector input on your image texture? If thats not the problem, can you add a blend with https://blend-exchange.giantcowfilms.com/?

@Sazerac I did at Vector Input in the node editor. So I think i figured out where the issue was. I started working on this character with the beta blender 2.8. I exported the FBX and then inported it into the final release of blender 2.8 and the issue doesnt happen anymore. I appreciate your help though!!!


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Is it possible to make inset not behave as edge support for subdivision surface modifier?
I would like to use inset, bevel or extrude tool with subdivision modifier, but when I make more loops they bring out cube attributes- as edge support, I would like that they follow curvature. Is that possible? I would like to use inset to ad  new topology on my creature, when I add 2 or three loops they flat everything.
this is mine
this is from book

You can use edge tools for example edge crease. https://docs.blender.org/manual/en/latest/modeling/meshes/editing/edges.html#edge-crease

Hello. You cannot prevent subsurf modifier from using existing loops. There are ways around it however. Attach a preview of your mesh, then it'll be easier to reccomend something specific.

I edit question because I don't know how to add image here in comment.

Images should always go on the posts, not the comments see How to upload an image to a post

I am still searching way to do this better. I now model with cage on, and after I inset move edge loop, use smooth, but it changes a lot mine meshes with shrink - than I use resize, to reshape. I would like that it would be possible to ad that loop and keep  more roundness.


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Vertex grips (dots) are missing in vertex edit mode. How do I get them back?
I'm newish to Blender, new to blender 2.8. My objects, in edit mode, do not have vertex grips(dots) when in vertex edit mode. I've increased the vertex pixel resolution from 3 to 6 in the Theme 3D view settings. I've ensured that overlays is on. I've reloaded default view port settings. I've uninstalled and reinstalled and still have the same issue. Its not always a problem but it does make it difficult to choose vertices when modeling. any help is appreciated.

Can you add a screenshot? If you have vertex select enabled in edit mode, the vertices should be displayed

Have you tried loading the factory settings? Sometimes even new installs use your old settings.

Am I crazy or am I seeing vertex dots in the screenshot?

I've not only loaded factory settings but I've also deleted the config file in the appdata 2.8 folder to force blender into creating a clean startup config file upon startup. I can assure you that there is no vertex grip in the screenshot. The vertex point of intersection is highlighted when clicked but there is no dot. Additionally this is vertex edit mode so all visible vertex intersections should have a dot

@Millard I think ur crazy haha I didnt see any

no, I'm just blind.  I looked at it more closely and there are no dots.  Really, this won't stop anyone from being able to model, it's just annoying.

there seems to be a lot of people having weird problems with 2.80, just no one else seems to have their problems.

Thanks for taking a look everyone. @Millard, your right it is annoying but I can still model. So its either back to 2.79 or suck it up and see how far I can get with the bug. If I do run across a fix I'll be sure to post.

I suggest you stick to 2.80.  The benefits outway the costs.  I assume you know about all it's cool features?

Im learning ;-)


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How to Apply Interpolation to Mesh casted Shadow
I have a simple question, you know how there is a way using color ramp on the texture to make the color sharp (Setting the Constant on ColorRamp) i wonder is there a way to do that same with the shadow that is casted by mesh in light and also be seen in vieport

In Eevee, turn on Soft Shadows and have a light with a radius to cause the soft shadows.

In the compositor, add a ColourRamp between the shadow pass and Exposure Node.


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Is where a way to pass data to material without realizing instances?
So, I have set up like this (3.1):

I generate some color (random is just for example) and send it to output to use it in the material. But the only way to make this work is to use realize instances node. So I want to know if where is a way to do the same thing without realizing instances (maybe some hacks), because it may be too costly for performance and memory.
You know the bunch of ways to do the same in particles (from instancer setting) and in the object (Object info ⇾ color), but seems to be they are not working...

I had this exact question like 4 days ago and actually thought "Crantisz is gonna show up and explain how easy this is and I'm gonna feel like a fool".
I can tell you the render speed is the same, I didn't check memory usage though

@TheJeran Well, I've checked. It's around 16 times faster to rebuild without realizing instances with simple cubes and spheres

oofta hadn't considered that. Hopefully, there's an answer. But if you don't know it, I'm thinking it doesn't exist yet. Which is weird cause all those instances have the correct value assigned to them. Dunno why it can't carry over into the shader editor.

This is now possible in 3.4 https://developer.blender.org/rB2f7234d3e1b
Store the attribute on instance

And then access it in shader menu using Instancer as the source.

Finally! Good news!

Yay! Didn't realize this


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Extrude Faces along Local Normals
I am trying to extrude faces of a cylinder along local normals. 3dsmax can do it easy, couldn't find how to do it in blender.
The extrude region option extrudes it as shown in the first example. I want it done like the 2nd example.

Are you actually running that version of Windows in 2014?

@Markasoftware Maybe it's that Windows theme that can be used in the Customize menu.

It looks like you want the Extrude menu (AltE).
For example 1:
There are several ways to activate the Extrude region operator:

Press E
Press AltE for the Extrude menu and select it
Press the button in 3D view > Tool shelf (N) > Tools > Mesh tools > Add > Extrude Region

For example 2:
There are two ways to get this result:

Press AltE and select Region (Vertex normals)
Select Extrude region (Vertex Normals) from the extrude drop down at the top of the Add section in the Tool Shelf

You can also two operators to get the same result:

Press E (Extrude), Esc (confirm extrude, cancel transform) and then Alt+S (Scale along normals).

For example 3:
There are a couple ways to activate the Extrude Individual operator:

Press Alt+E > Extrude individual faces.
Press the button in 3D view > Tool shelf (N) > Tools > Mesh tools > Add > Extrude Individual

Local orientation
Note that in blender, the Local orientation is based on the rotation of the object. The above methods use the normals of the extruded geometry, however if you want to extrude along the objects' local orientation you must do something slightly different:

Set the transform orientation to Local in 3D view > Header:

With the geometry you want to extrude selected, press E and then Esc to cancel the transform. If you are in face select mode you will notice you can see the indicators for faces where the new faces have been created:

Press SShiftZShiftZ and move the mouse:
Shift locks the axis that is specified, so if the other key pressed is Z, it will scale only on the X and Y axes.
Pressing ShiftZ twice ensures that the objects' local orientation is being used. Global orientation is always used by default (first keypress), and then the orientation specified in the header is used after the same axis constraints are specified again (second keypress).

Note that you can also use this technique for extruding along the Normals the same as the first methods, just select Normal as the orientation in the header instead of Local.

It extrudes only individual faces as shown in example 3. I want them to be extruded as shown in example 2.

Cant get the second option to work. Pressing E after I pressed Alt-E /Region doesn't do anything, moreso, pressing Esc cancels the operation, and subsequently, Alt+S just scales my selected faces.

@SyedImran Alt+E > Region (Vertex Normals) starts the transform right away (pressing E again therefore does nothing). Esc cancels the transform part of the operation, but the new faces will be there. Alt+S should then scale the new faces, not sure why that part didn't work for you. I have updated my answer with more detail.

Dont know why its not working, and you seem to have Region (Vertex Normals) in your dropdown menu, and I don't :/ I only have Region E and Individual Faces. Are you using a different version of blender? I am at 2.69

@SyedImran Oops, good catch. I'm using the 2.7 release candidate (unstable).

So I presume there is no way to do this in 2.69.What I am doing now is adding 2 other loops and then scale the inner faces. A bit tedious, but hope that it will get fixed in the upcoming version.

@SyedImran I just did it in 2.69, so it is possible.. Are you sure you followed it exactly? Select geometry > E > Esc > Alt+S. I added another way you could try too.

What do you it works now. I was pressing Alt-E then Esc. Doesnt work that way. Cheers!

@WilliamKappler I suggest you ask that in a new question :) (and link to this one if it helps provide context)

@gandalf3 excellent answer!, I'm following this tutorial, but I don't have the "extrude vertex normals" option, so, with your answe, I was able to reproduce the same result (by following the "for example 2:" section) - I'm using Blender 2.64

@Mauricio Glad it was useful :) Just to make sure you're aware, 2.64 is several years old at this point. The current version is 2.79, though 2.8 has been in development for about a year (with many large changes including a complete UI overhaul) and is nearing release. If you're just looking to learn blender and don't have any special reason to use 2.64, I'd highly recommend learning 2.8. You can find the beta release here.

@gandalf3 I downloaded the 2.9 version and I'll continue with this new version - I hop I can follow these tutorials as expected. Thank you for your help.

This is an answer to MrFlamey's question since I don't have 50 reputation to post a comment.
To extrude faces along face normals, as opposed to vertex normals, extrude  the polygons with Mesh -> Extrude -> Region, move them with Mesh -> Transform -> Shrink Fatten and hit S key to make offset even.

An alternative is to use the 'Solidify' modifier. This will also do the same as extrude region (vertex normals), although you will get more control, and will be able to change the parameters later.
However, I'm still unsure if there was a way to extrude faces along face normals, as opposed to vertex normals, as Solidify uses vertex normals. This means that if you Solidify a box with a thickness of 1.0, the sides of the box will not actually be 1.0 unit thick, however, if you do the same to a sphere, the sides will be almost exactly 1.0 unit. This is because the displacement is calculated from the original vertex position to the new vertex position along the normal of the vertex, not the face. Using extrude individual faces will use the face normal, but the extruded parts will not be continuous. I would LOVE to see a way to extrude objects along face normals that avoids odd deformation and gives a continuous surface with consistent thickness on all kind of object shapes, regardless of how angular the corners are.

Easy way: Select the ring of faces, goto Mesh > Extrude Individual Face (as shown in other answer) then press ESC then use ALT S to scale the out.
If you don't press ESC you will scale faces, if you press ESC you will only scale along normal i.e. extrude out.

What's the point of cancelling the transform? AFAIK Extrude Individual gives you the same transform as Alt+S..

This is quicker than your drawn out example and I think I explained it already. Does it work does it and answer the OP question? Honestly I am becoming reluctant to post on here.

Sorry, I did sound too harsh.. I was merely wondering what your reasoning was, because I didn't understand completely. For me just pressing Alt+E > Individual and then moving the mouse gives the same result as pressing Alt+E > Individual, confirming the extrusion and then pressing Alt+S (which is how I understand your answer). I think I must be missing something..

The best answer I've seen yet on this topic is to press space and enter "Extrude And Move On Individual Normals", as seen here:
https://blender.stackexchange.com/a/63865/

Thanks eobet!!!! Problem solved...I literally have no idea why you're not the number 1 solution

This is the top Google result on this question, but I don't see the best answer I've seen yet on this topic, which is to press space and enter "Extrude And Move On Individual Normals", as seen here:
https://blender.stackexchange.com/a/63865/38603

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


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Cannot find the 'Manipulate Object Centers Only' button. Is this an addon?
Cannot find the 'Manipulate Object Centers Only' button refered to in the book 'Blender Foundations'. Is this an add-on?

Does this answer your question? Where is the "Manipulate Centers Only" button in Blender 2.8?

I would post a comment to the above answer, but apparently I need 50 reputation for that so I have to add an answer instead.
The book the OP is referring to is "Blender Foundations: The Essential Guide To Learning Blender 2.6", by Roland Hess. I have this book myself and the text where the author refers to the Manipulate Object Centers Only is in a tutorial where we are trying to box model a simple chair. The effect he wants to achieve is to splay the 4 chair legs out from each other by selecting their bottom faces and using the scale tool:

However, if you just select the bottom faces of the legs and hit the S
  key, they will move apart as you scale them up, but they will also
  grow in size. We'll try a new pivot style to solve the problem. Beside
  the pivot style menu on the 3D view header is a button called
  Manipulate Object Centers Only. This magical button causes
  transformations to only affect object centers, not their component
  structures. The effect works both in Object mode and Edit mode. In
  this case, selecting the four faces on the bottoms of the legs and
  enabling Manipulate Object Centers Only will move the faces away from
  one another when scaling without actually changing their size.

Note how he mentions the setting works in both Object mode and Edit mode, this seems to imply that we were meant to switch out of Edit mode to Object mode, switch the setting, the come back to Edit mode but he doesn't implicitly tell us this in the book. Having said this,  and after trying it myself this setting doesn't appear to do anything in Edit mode as the above users mention.

When in object mode it should be on the Header in the 3D view, next to the pivot point selector:

Note that you can also toggle it with Alt, (comma).

It does not appear on the header, which is where I expected it to be. Can't tell when it's on or off using CTL ,   Corrupt install?

@user2633 Make sure you are in object mode. Is it possible you pressed tab or something by mistake and switched modes?

The book says it should work in both Edit and Object modes, and the step I'm working on is in the Edit mode. Is the book wrong?

I can't find any commit that removed this option for editmode, and tooltip clearly says Object and Pose mode only. What Blender version was the book written for?

Yup, totally doesn't work in edit mode.

@Rayzor53 I think the only way to do this in edit mode is by separating the meshes into objects, performing the transform in object mode, and then rejoining the objects.

I found it! Finally able to rotate my objects. But somehow the hotkey [ ALT+, ] doesn't work for me hahaha. solves the problem anyway!

In Blender 2.8 it's at the bottom of the pivot point drop down menu.

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


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List of un-assigned keys in Blender 2.69
How can one obtain a list of un-assigned keys in Blender (i.e. Q, Alt-Q)? Is there a script for this?

Not that I know of, but you can view all the shortcuts in User Preferences > Input. There is also an operator to test for key conflicts (Space > Search > Test key configuration for conflicts). Note that this prints to the console.

What would be the semantics of this operator? I've searched for it on the online manual.

I don't think it can be nice and practical to list all un-assigned keys, since there obviously are too many posibilities with combinations. Furthermore, same keys can be used in different modes and contexts without conflicts, which extends the possibilities even further.
However, as gandalf3 suggested, you can view all shortcuts in User Preferences > Input. Also, when switching Filter Type to Key Binding, it allows you to search specific key that is currently assigned:

If nothing is filtered, then congratulations, it hasn't yet been assigned to any operators among all contexts. You can use it 100% safely:

for what it's worth, I still think it would be useful to display the list of unassigned keyboard shortcuts upfront, rather than try/error manually one by one. I mean: computers are perfect for those loop tasks...

@ling Couldn't agree more. I also wish there was a way to search for explicitly the exact key you're entering in the search key binding field. Even made a request for it that you could support here: https://blender.community/c/rightclickselect/y9nz/


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why does fur after combing act unpredictably?
I have created a model of a mandrill and I’ve been using particles to make the fur.
Because the fur throughout the body of a mandrill is very different, I’m duplicating parts of the whole mesh and slightly scaling them down to stay inside the big mesh. So I have a “chin" mesh with one particle system, a "face/top head" mesh with another particle system, etc.
I guess I could use vertex groups for the same purpose, but several tutorials seem to use the duplicated-mesh-parts approach to keep the flexibility of retouching the whole mesh if necessary.
On some of the particle systems - e.g. the chin - I’m getting the result I’m after.
On others - e.g. face/top head - even though the particles look fine upon creation, once I comb and render, they get a life of their own and point to different directions, clump, etc.
I have recalculated the normals, checked deflect emitter and even tried applying the particle systems to vertex groups created in the whole mesh (rather than using the duplicated parts). But I’m still getting a very sad looking mandrill.
Any ideas?
Thank you.

Particle problem can be hard to solve without knowing the specific settings. I highly recommend that you could upload the problematic scene, e.g. you can upload it here.

You may check whether the hair dynamics is enabled, or whether set an initial velocity, or whether have it influenced by other force field in the scene.

Thank you very much Leon. I uploaded the file here. Hair dynamics is not enabled and I don't seem to detect an initial velocity or other forces; but I'm also learning as I'm going, so your opinion is appreciated

Looks fine for me.. Could you add some screenshots highlighting the issue?

In this folder you'll find two renders, one before and another after combing. The combing I did was simple, just pushing the particles to the back, but they all went in different directions, as you can see. I'm not able to shape the fur as I want, as a mandrill would look like.

@user2694 It looks strange, and problematic in the latest dev version, Anyway, you can try to delete the current fur then create a new one, to see if problem still occurs. Since it looks fine for me, too.

Thank you Leon, I'll give that a try. I appreciate your time and help.

When setting up particle hair we normally configure a small number of hairs, then use children hairs that get created around each existing hair to fill out for the render.
The children hair settings have options that make them curl up or clump together around the parent hair. I think the bending and clumping you see is the children hairs being deformed by these settings after they are shown. Most likely this is because in particle edit mode you aren't showing any children, so when they show up in object mode they look much different. While in particle edit mode you can turn on the option to display children hairs. This is in the toolbar T under Options.

For performance we normally only display a portion of the children hairs while grooming the hair, and use more hairs for a better final image. These options are found in the Children panel of the particle settings. Display is how many children we see in the 3dview, while Render is how many are used at final render stage. If you set these the same while grooming the hair you will see less change at render time. Once finished grooming you may want to turn Display back down to keep the 3dview responding.

Thank you very much sampler. Actually the difference I'm seeing is not before and after visualizing the children. It's before and after combing. This folder contains two renders, before and after combing. What I don't understand is why the combing process makes the hairs go in all different directions rather than arranging them according to my comb strokes. Thank you.

Check to make sure that the setting for your modifiers are the same for view and render. If, for example, you have a subsurf modifier set at 1 for view and 3 for render, it will throw your hair wild. You probably want to keep the render value the same, but if you set your subsurf view option to 3, it will slow down your machine. I'm trying to figure out now how I will work with a high-res mesh and a low-res mesh with the high res set to invisible. I know this is doable, but it introduces some complexities.


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Can fluid respect soft bodies (or any deformation!) in blender?
Right now, I have a render that looks something like: this.
As you can see, the fluid is ignoring the soft body simulation.
Is there any way I could make the fluid respect the soft body simulation?  It doesn't need to be good - this isn't an engineering project - but the fluid needs to follow with the soft body, more or less.
Is there ANY way within blender to make a fluid simulation respect any deformations at all?
Thanks for the help!
PS: What does it mean to Apply a fludism modifier?

In short, no. The fluid sim won't interact with any other simulator. But there is a way around this limitation.
For the obstacle object, selected Export Animated Mesh, this will animate the mesh itself, rather than simulating the mesh. As a "real" mesh, the fluid sim will treat it like any other mesh, and react to it appropriately. However, this will have to be repeated anytime you want to change the physics simulation. Incidentally, this also means that the soft-body cannot react to the fluid sim.

Does it matter if we bake the soft body or the fluid animation first?

From my testing, you don't need to bake the soft-body first. Blender seems to be able to solve the simulation together fine. But to be sure, I would recommend baking the softbody first to ensure the right geometry is passed to the fluid simulation.

Hmmm, as soon as the object hits the soft-body bowl, the fluid just becomes a cube again!  Do you know any likely causes, sir?


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Adding UV to object
I am new to blender. I downloaded a blender file and there's the object that I downloaded but it's in gray color. I look at the UV editing and I can see that there are already preset colors, I just don't know how to add it to the object. Can someone please help me with this? Thank you for helping!

can you post some pics of what you've got at the moment, such as node setup, the uv settings, etc?

Sure thing! Thank you for asking

Are you in render mode?

I wasn't! Thanks for the help!


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Object has no color dispite whatever I do
The figurine has no color dispite whatever I do. The material was assigned to the object but it still doesn't pick up any color. The only colors are the white clouds and the green grass that the figurine is standing on. And when I click on materials, the tiny image turns white!

You haven't activated nodes and the texture isn't assigned to the material, but as brush.

You need to assign your texture to the material. Create the Shading workspace by clicking the plus button next to the other workspaces or change the 3D View to the Shader Editor

Activate Use Nodes then select the material you want to edit and then set up a basic shader with a texture like in the image below.

Thank you so much for answering my question!!


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What would be the proper lighting technique for my scene
I have created a scene in which a spaceship is under gunnery fire from laser bolts. The ship is surrounded by an energy shield which glows when the laser bolts impact it. The bolts are a particle systems. On eevee 2.81 render, the point light illuminated the glowing shield but the ship itself is quite dark. In fact, the shields glow too bright. What would be my next method to properly light up this scene? One which would brighten up the ship and shields without blowing out the shield glow? Thanks
OK I have answered my own question it would appear. I deleted the point light and added an area light instead and the details of the ship show up as in my 3rd image. I will play with the bloom settings in order to get the impacts bloom under control. All good here. Question can be closed.
Danny

For such a purely visual question, without attaching an image we’re (literally) shooting in the dark.
I would say try turning the shield glow off, illuminating the ship first, then bring the shields back incrementally.
John

The way this is currently phrased invites opinion based answers. We don't even know what render engine you are using, which seems crucial to answer a lighting technique

Hi everyone, I have added the render engine and an image. As for the description of the issue, for me it is as clear as my comprehension of the english language can allow me, so if this is still not clear, then my english isn't at the standard I think it is.

I have added 2 images which I hope it will help with clarifying my question. The shield glows only on impact and this lighting is a point light set at 500 W. I played with the intensity and it gets worst the brighter I turn on the light. I tried bringing in the light but the glow gets worst as well. Am looking to get the ship bright enough so it's details are visible. I hope this clarifies the question.


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Rendering a 2.79b file in Blender 2.80
I have created a shockwave in Blender 2.79b. I used 2.79 as it was easier for me to follow the tutorial. Now when I open that blend file in 2.80, the render results are not the same as 2.79b. I tried with both eevee and cycles. It seems 2.80 isn't recognizing the material and the compositing I did in 2.79b. Is there a way around this? Thanks

Danny

Are you using Blender Internal for 2.79b? 2.80 doesn't have BI for rendering. Or is there a node setup screen shot so we can take a look at what might be the problem.

I think it could be caused by the fact that in 2.79, I added a new material and changed it to halo. I can't find this "halo" in the material in 2.80, the only place I find it is in particles. I just loaded the blend file in 2.80 and there is no particle system enabled. Could that be the issue? I will get node setup screen shots and post them.

Definitely yes, some obsolete feature will no longer support in new Cycles build. They will possibly contain in custom properties, you can check that block to see what is thrown there.

10-4. Figured it could be that. I just added my nodes to my original question. So I guess I have to figure out how to do that shockwave tutorial in 2.80 instead of 2.79.... seems I will be learning Blender for years to come lol.

You got a Blender Internal render engine setting. It is not for Cycles, they don't use same material system(although they are all using node).
You will not able to directly import this material into Blender 2.80 and further version. Since they've discarded the old BI system and adopt EEVEE, which share the same material system, instead.
You might find out that node setting in 2.81(newest one) could probably do the same effect with more elegant node setting. Keep on keeping on.

There are some add-on which can help you to turn BI material into Cycles one. Then you can import it to 2.80. But AFAIK, add-on only work on simple material. And the setting should  be messy and need further cleanup. Which is kind of...useless, in my mind

I just downloaded 2.81. Will read up on the changes and attempt that tutorial with it. At the very least, I will LEARN, which is my number 1 goal.... completing my project is a close second!


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How can I control which borders are affected by the insetting tool?
I am trying to modify geometry in a model I am working on. I want to inset one of my forms but only want the border at the top and not the sides as I want to extrude it inwards. I have tried with the boundary and individual options "on" but I can't get it. Am including an image. I must be close, but would need a hint as to how I can do it. Thank you.

Could you provide an image that shows the effect you are looking for? Your description is not sufficiently evocative.

I wish I could mate, but that image would be the final effect I am trying to achieve. If you reference the included image, I used an inset as shown. This resulted in 4 borders (the bottom one is hidden inside another mesh). So... is there a way to use inset and only have the top border and not the side or bottom borders when using inset? I want to extrude inwards the face highlighted in this image so as to create some sort of a trench with only the top border showing.

Perhaps you could sketch it, or find an example online?

Just added an image of what effect I want to achieve. Thanks

You can only control the boundary edge.
It's easier to

Select the top part
Extrude along normals
Check Offset Even

Perfect. Thanks very much!


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How do I smooth out two objects (with low poly) that have been unioned in blender 2.8?

I'm creating a character for a new game I'm developing and the character is supposed to be very round with plump arms and legs. When i tried to boolean union the round head with the round body it became jagged. I think it's because of the vertices and their connections but I even if I'm right I don't know what to do about it. Any suggestions and is it something that can be solved by sculpting, modeling, or both?
The goal is to have the character rigged and animated so just having a temporary visual modifier isn't what I'm going for. I just want the head to rest on the body but still be able to move it around when I rig it.
I also need to add arms and legs to the main body mesh too.
I put the blender file here in case anyone wants to take a look.

Maybe worthwhile downloading experimental build 2.81 and using the voxel remesher. It would solve this problem as that is part of what it is built for.

@barkest I just gave it a try and even though it seems like a pretty useful tool, it mainly just changed my geometry so it didn’t really fix the problem. It’s just have me fewer vertices to worry about but not by much.

You can join two spheres this way and adjust for your character as the process should be the same.
Create a sphere with 16 segments and 8 rings

Create a second sphere half the size

With the smaller sphere selected go into edit mode and line up the edge loop with the larger sphere. You can do this by eye

Add a boolean union to the large sphere and select the small sphere to join

Apply the boolean and shade smooth with a subdivision surface x2

To transform the body I would add a lattice with a vertex group on the base mesh to limit the lattice influence and this way you keep the head round

you can then transform the body shape as required

I think that’s a perfect way to solve my problem if I only needed those 2 objects together but what about if I add arms and legs to it? Any quick eats around that? @barkest


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How can I smooth out my model's sharp geometry after doing a boolean union on blender 2.8?
For this model I had several separate smooth objects and then I joined them together with the boolean modifier. After that my model became sharper and jagged at the points it connected. The 2nd picture is the inside of the body looking at the arm. I've tried so many sculpting and editing tools to try to smooth it out but it doesn't work... The tools seem to have little effect even with the dyntopo tool. I've also tried to merge vertices but it said "0 vertices were removed". Subdividing and un-subdividing the arms to match the body's vertices before attaching them did not work either. Please help.

It seems like your mesh contain duplicated vertices. Maybe try to merge by distance at once? Or some custom normal or attribute

I just tried to merge by distance but it said that "0 vertices were removed" unfortunately. Thanks though

Inner faces possibly. or inverted normal. Try to check both

What do you mean by inner faces? Are there not supposed to be faces on the inside/is the object not supposed to be hollow? And I don't know what you mean by inverted normals. I also changed the 2nd picture to show you the inside of the body/arm. @lemon

A bit too few elements on the pictures. Could you upload your file? Use this link if you want to do it: https://blend-exchange.giantcowfilms.com/

by inner faces, I mean faces that are inside the mesh, joining two opposite parts of it

ok, have the file. This is inverted normals. Enter edit mode, select all and Shift+N. But won't solve all. The base problem is the geometry is not good at all. Will be hard to fix. Should at least start from mesh parts that are approximatively at the same level of details.

That helps me a lot so I'm very grateful. This is my first question on here so I'm pretty new to how this works but don't you want to post the answer so i can confirm it and you get points? @lemon

And last question. If i continue using the model after I make it only "look better" using inverted normals but i don't change the differing levels of detail, will that have a heavy negative effect when I rig it and animate it or not really? @lemon

Well, I don't exactly know what you aim to do, but I'd say that this model won't be the best for rigging. Main causes main articulations seem to be at the boolean intersection and you can see that even not rigged it does not fit nicely.PS: by inverted normals, I meant this is partially why their is the problem, was not saying using them but make them not inverted.


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Make closed curve not closed. Blender 2.8
I have a closed curve. I want to open the closed curve to make it not a closed curve anymore. I made the curve closed by using Alt+C in Edit mode.

All you need to do is click Atl+C again to open the closed curve.

Lol, so stupid )) Thank you ))


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Binding Shape Keys to a Empty with Distance Influence
Is it possible to bind shape keys to a empty and depending of the angle and distance it has influence on a character or object?
Example:
https://youtu.be/zM3psSxWTYM?t=39
Basically exactly the same, I timestamped the video at 39 seconds
Here's a .blend file of what I got so far:
https://1drv.ms/u/s!AnxeMsAWKW1ci1YaB1CoPcZJmphi

You can use drivers to do it.

I looked into drivers but I'm a freshman with blender and I can't seem to make it work. This is what I have so far: https://imgur.com/a/UFO88VM

Ok, I managed to make it work but my issues is that the shape key gets applied equally to the body. For example I'm coming from the right side but the character changes equally on the right and left side. I would like to have it independent. Currently it just increases or decreases the total value of the whole shape key.

could you have some more details editing your answer or providing some picture (hard to figure out exactly what you mean)

Sorry for the bad quality, but I think it's good enough: https://gph.is/g/EqNBx35 as you can see the shape key gets applied equally. I want it to have influence on vertices depending from which side I'm coming like in the video above.

To tell the truth I see nearly nothing on the animation. But think I catch the point: you may either have one empty by shape key or use a different axis of the empty for each shape key.

Mmmh, I was hoping to have all in one like on the example video above, where the sphere applies a shape key to vertices in range instead of the whole body.

If the shapekey includes both head and body morphing, I think that's not possible

Technically yes but in this case I just used the vertices group of the upper abdomen. What would I have to do if I just use a shape key for the head for example?

Oh ok good. so that should work. If not should find a way to show the setting either adding images in the question or uploading the blend file.

I'll prepare something new since I can't share the model in my example gif.

I added a .blend file to my original question.

ok, get it. But what is not working here?

The controller only influences the strength of the shape key globally, but I want it to have only influence on vertices in range like in the making of video I posted.

Is it due to "var + 1" which should be var? Or by range do you mean keep only an interval inside [0,1]?

I don't think what I want is able to work with my current setup. Like I said, I basically just have a controller of the global shape key so far. Depending on how close I get to the character the shape key gets applied on the WHOLE character from a 0 to max value. I don't want that though, I want a spherical influence area which has impact on vertices in range. I don't know how to phrase it differently. All I can say is that I want exactly the same like the wolfman making of video timestamped at 39 seconds. ^^

What I need is basically something which has influence in a spherical area, which applies a shape key to vertices in it but smoothed. Let's say vertices in the middle of the sphere have a shape key value of max. and vertices with more distance to the core have less influence till they reach a value of 0 at the border of the sphere. I hope this clarifies better what I want.

oh ok... simply use the distance in the driver parameters. Use another empty and place it at the center of the head. Then set distance in the driver between this last empty and the controller. You'll have a 'var' and if want to have more amplitude just set var/3 (say) in the expression. Need I write something about that in answer part?

I tried this, but it still seems to apply the shape key on the whole face equally: https://1drv.ms/u/s!AnxeMsAWKW1ci1eEYb4LQkVM7L5d
If I move the second sphere fast on the x-axis left and right it's pretty obvious that this is the case.

The face movement are very small on this shape key. But no, I don't see what you say: that seems progressive as the controller moves.

The whole face at once is progressive yes. But not from left to right and vice versa. If I want for example half the face only morphed it still seems not to work.

I get the point (at last) but failed to find a solution. Have played around 'vertex weight influence' modifier but was not able to make it work

Thanks for trying though, I will ask more around and try to solve it myself simultanously. I can imagine it comes down to scripting.

If you find something, please ping me (the subject is interesting)


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Rotation tool not tilting
I have been trying to tilt a selected part of an arm to bend limbs, I try to tilt it to the right. However, it goes side to side.
Here is an example.
https://gyazo.com/e7639bcb68cb1c6a57ed61ffab05f9c8

Select the armature and go to the "object" tab on the right side of the screen (orange box) and tick the option that says "In Front" (it's under "Visibility" or "Viewport Display" or something). This will always draw the bones in front of the mesh.
Change your rotation space to "Local" and pivot to "Active Element" at the top of the screen. With the armature selected, press CTRL-TAB to enterms pose mode. At the top of the screen, click the gizmos icon to bring up the drop down menu. Make sure the Rotation gizmo is activated.
Now you can see which axis your rotation is affecting by clicking and dragging the colored circles.


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Strange, indescribable color glitching near edges when using viewport shading in Blender 2.8
I am new to this website. I've been having a problem with viewport shading after installing 2.8. I am trying to make a VHS cassette (for no particular reason), but I have a problem that hasn't been addressed yet, from what I know.
The cassette is supposed to look like a regular VHS, of course. But when I enter look dev shading, it ends up looking like something I can't really describe with text.

It does this strange thing, adding artifacts to the thing, particularly near the edges of the mesh. The artifacts get smaller as I get closer to the mesh. They seem to reset when I move the camera, beginning to grow back when the camera stops.
Hopefully, someone can find out how to help me out here. For now, I'll just continue working on the model. I am using Eevee, and the computer I'm using is a Dell Inspiron 3668. As mentioned before, I am using Blender 2.8.

First make sure that your hardware fulfills the minimum requirements to run Blender 2.8 (https://www.blender.org/download/requirements/). If it does, update your graphics driver.

Seems like @rjg is right; I updated my drivers after messing around and discovering the driver manager, and I'm no longer encountering these artifacts.

I was having the same problem and changing the 'surface' property of one of my materials seemed to fix it at least temporarily. I honestly don't know if that actually fixed it though.

Robert Gutzkow solved this question in the comments.

First make sure that your hardware fulfills the minimum requirements to run Blender 2.8 (blender.org/download/requirements). If it does, update your graphics driver. – Robert Gützkow Aug 19 '19 at 7:18

Fixed it for me by checking and unchecking Screen Space Reflections in Render Properties.


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Cannot modify or delete mesh without it collapsing
I've been working on a model for a game, and found out about Shape Keys for clothes/armor that can be changed out. When I tried to squish the torso, I found out I can't scale it at all. Then I found a rip in the mesh - which is strange since its from an applied mirror, and the cut isn't on the other side.
It turns out this cut has to be from Cthulhu or something, cause it completely wrecks everything.
https://youtu.be/XbFRfi2QcJM
I made a video showing what happens if I duplicate the other side, or delete the vertices around it. It just goes berserk and collapses on itself.
The only modifiers on the effected mesh are smoothing and armature.
Does this mean it got corrupted? Is there a way to stop it from becoming a black hole and devouring the entire upper torso? Or is the only option starting from scratch?
Edit//

Is it possible for you to upload your .blend file? https://blend-exchange.giantcowfilms.com

I added the file to the main comment, thank you for taking a look!

The Upper Torso shape key likely needs to be removed, or at least you need to disable the Shape Key Edit Mode option

https://imgur.com/SA25m0J Its definitely related to the shape key! Thank you very much, I had to delete it to make new ones and figured out the stepped I missed in making it. Thank you again!


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What does the "blend" value do on a spotlight in cycles?
A spotlight has a setting in the properties window, lamp tab, then under the section "Spot Shape" called "Blend", what does it do?
The tool tip says "Softness of the spotlight edge" yet setting it to zero did not make the lamp's edge noticeably any sharper.
The image on the left the blend is to 0 on the right it is set to .5

TLDR Reduce the size of the lamp (something around 0.01 BU).

The blend value still does what it always did in the blender internal render, make the edges of the spotlight softer.
The reason you can't see much difference when you change the blend value is because of the lamp's size. (Independent from the blend value if you change the lamp's size the light and the shadows will get softer, or sharper.)
Simply set the lamp's size to something very small (around 0.01 BU). Not the angle of the beam, but the size of the lamp (top "Size" field). Now you can adjust the blend value. There isn't that better.
In the picture below both lights have the blend set to 0, but the size is different 1 BU for the pink light, and 0.01 BU for the green light.

For additional reading the cycles documentation for the spotlight is rather short, we have to go to the BI side of the docs to get more info on the blend setting.


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What are the differences between rigging with bones using bones constraints or just using object constraints?
I'm specifically talking about mechanical rigging here.
I understand bones and armatures are necessary in organic forms where there is deformation in the object, but for mechanical rigging where no parts deform, but only move, does using bones help any?
To me it seems simpler to just use object constraints when rigging mechanical things.
What are the differences between using bones or object constraints?
Are there any benefits bones have over object constraints?
Is there anything that can only be done with one method?

If it's just separate, undeformed meshes you're using, you could use object-level constraints.  But there are even some benefits to using Pose-space for mechanical stuff as well:

It makes things easier to revise.  If you decide to change the mesh after you've constrained it, you may run into some issues if say, the pivot point has changed on that object.  Same thing if you've parented it to another object instead of constraining.  If you had a bone deforming one object (and then another bone constrained to that bone) you now have a revisable system.
It allows for some pose-based tools, such as saving poses.  Granted, this benefit is only useful if you find you want to re-use key positions a lot.  If it's just a piston or something fairly cyclical, pose-saving isn't all that useful.


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How does the "Selected Objects, Data and Materials" option for Make Local work?
I can not get the "Selected Objects, Data and Materials" option in the Make Local menu to do anything different then just the "Selected Objects". I'm expecting it to make not only the object but the object data and materials local, yet it is not.
I have the same trouble with the "Selected Objects and Data" option.
I have tried with different linked objects, and in a saved and unsaved file, yet still the objects' data stays linked.
Here is a gif showing what I'm doing and that the object data is still linked to the source.

seems to work only after making the object local

O that is weird (bug territory) if you click Selected Objects and Data or Selected Objects, Data and Materials once, it only does the object. But twice works.


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Is there ever a reason to set the scene camera to a non-camera object?
Set Active Object as Camera a simple function, CtrlNumPad 0, used to change the active camera yet such a problem for so many.
I know the use of it for cameras (quickly switch between multiple cameras), but is there any reason to set an object as the scene camera?
Using blender terminology, I'm specifically asking about objects with the data type of 'MESH', 'CURVE', 'SURFACE', 'META', 'FONT', 'ARMATURE', 'LATTICE', 'EMPTY', 'LAMP', and 'SPEAKER'. (every object type except 'CAMERA'.)
With the scene camera set to a mesh object it will render nothing (or crash blender). So what is the purpose of this?

As the Manual says

Remember that the active “camera” might be any kind of object. So
these actions can be used, for example, to position and aim a lamp.

I don't recall ever doing this, but the reason to use a non-camera object as the scene camera is to take advantage of Blender's camera movement tools to position the object.  You can, for example, select a lamp and make it the camera, and then lock camera to view.  This way you can navigate around the scene and the lamp moves with you.  When you've got it positioned where you want it, unlock the camera from the view and go back to using a reasonable camera.

For the record, I rendered a scene in Eevee, Cycles, and workbench using the LAMP as a camera. All three worked. As for MESH, it seems the "camera" works from the origin so is usually inside the object.


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How to make a procedural white birch bark material in cycles?
How can I proceduraly create the dark lines as seen in white birch (paper birch) bark?

This is the exact type of effect I'm trying to replicate. Random sized "lines" in the bark, yet they all run the same direction.
You can see in this picture, that this variation of birch has a slightly different bark pattern. Here the lines are much longer. (At this point I don't care about the random dark blobs, they are mostly knot holes, but if somebody wants to include that too... :)

-pixabay

Making a birch shader completely procedurally is quite a challenge, this is my version:

(download blend file below)
Like the other two answers already say: you achieve these effects with stretched noise textures, color ramps and mix nodes. It takes quite a bit of time and experimenting to figure out which noise looks best for the specific surface. I mainly used the standard noise and musgrave noise.
Unfortunately I can't walk you through the whole shader, but here are some steps that helped me:

research the node wrangler add-on to prevent headaches

work from large-scale noise to small-scale noise. Here I created the big random blotches first, after that the horizontal lines and at the end the tiny black spots. That helps keeping the proportions right. It needs to look right from distance first, keep the details for later.

look at your noise textures isolated. With the node wrangler add-on activated, you can Ctrl+Shift+ leftclick a node and a viewer gets created.

stay between values of 0 and 1. When you start to mix the different noise textures for more complex noise, always look at the isolated result and make sure that the values don't go negative or exceed one. Your shader won't break when you have values below 0 and over 1, but it makes it much harder to work with, because these values can't be displayed.

group components to keep your overview... but: don't group them too early. Isolating nodes doesn't work in groups and this makes it really hard to "debug" node-groups, when you want to find one specific pattern.

Here are the horizontal lines I used:

create noise texture
scale on z axis by mapping coordinates (i used 4, 4, 40 in scale)
a high contrast color ramp for sharp edges
i used only the R channel of the noise

The result of that color ramp could then be used to

mix between shaders (as a factor in mix shader node)
create a mask, e.g. for colors or shader properties like roughness
be mixed with other noise patterns to create more complex and interesting noise
...

Here is the file:

Here's what I could come up with.

It mostly relies on using a Voronoi texture squashed in Z axis, and a Color Ramp node to control the "spot radius" for the smaller spots.
For the bigger branch dark spots or nodes, again the same setup of Voronoi texture with a Color Ramp node to control the blotch size, the only addition is mixing texture coordinates with a noise texture to make them more distorted and irregular looking. Have in mind I didn't bother recreating those "inverted V streaks" visible around the branch nodes in the second image, those don't seem trivial to achieve without some sort of image based texture.
Here is the corresponding node setup

You can adjust the spot amount/density with the Scale value of theVoronoi textues, the "squashiness" by varying the Z scale value under the Vector Mapping nodes, and the size by sliding the control points on the Color Ramp nodes.

I came up with this but if I were to go this route I would use this setup as a mask and create the other two textures independently.


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Geometry Nodes - How to change points density along curves, if curves are instances?
I can change points density along quadratic Bezier by moving central handle, like in example_1.
Example_1.

But if quadratic Bezier will not be straight, I could not change its points density without changing its shape. Also it will not work, if I want to manage quadratic Bezier points density by curve parameter node.
The best solution will be if resample curve node will work, as I need. But it doesn't. Resample curve node input "count" field does not work like a field on the same curve to which it is applied.
In the example_2 resample curve node works like a charm when I feed it with curve parameter of the first curve.
Example_2.

But in the example_3, when I feed it with the curve parameter of its own curve, it works very similar with example_2.
Example_3.

Is it a bug?
So my question is: How to force curves in example_3 to be sampled like curves in example_1?
Better resample curve node, let's called it "asymmetrical resample curve node", is very needful for generating plants. Because plants usually have progressive or regressive density of branches along trunk, and leaves along branch.
My goal is to build realistic environments with lots of different full-procedural plants, using geometry nodes in Blender 3.1. I made a giant research and proved that it is already possible. To imagine how far I am you can take a look at couple of my answers here Geonodes: Apply point index to group node input and here Geometry Nodes - Generating geometry per instance
Example_4. Thanks to Hans Goudey.

In this example i use Hans Goudey answer. It gives me ability to change samples for bended curves. But unfortunatly in this example i lost the ability to change samples of second range curve along first range curve like i did in examples 2 and 3. So my question is not solved yet.

Finally the solution is to use "subdivide curve" node. Because this node input field works correctly with curve parameter of the same curve.
Fun:

All setup:

Inside "Curve_To_Points+" Group:

Group input field "Point_Density" works well with curve parameter of the parent curve. So i can control density along all curves. At all ranges of the plant model.
Using "Modulo" math node i select and delete all unneeded points. This way i can keep original count of the points after curve subdivision.

The resample node has a single count or length parameter for every spline in the curve data. That's just how the node works, it's not a bug. However, with a bit of work, the sample curve node can give you any distribution of points in the curve that you want.
Also, It might be better to use a different order when building the tree of instances-- first build the geometry to instance with the curve sample node, and then instance it on the "stem" of the plant.
The float curve node combined with the sample curve node can give any density of points along the curve that you would like, though the float curve node could be replaced with any set of nodes that remap the distribution between 0 and 1.

Thank you! :) But if we will firstly build a leaf and then instance it along the branch, then all leaves will be identical. And if we will firstly build a branch and then instance it along the trunk, then all branches will be identical. And if we firstly build a tree and then instance it along landscape, then all trees will be identical. So this is philosophy of ready collections. This philosophy is not bad, but it is not new, and it already have been realised everywhere. We even do not need geonodes to do so.

In fact this philosophy is quit opposite to philosophy of full procedural 3D environments, where all things are unique, and are generated at there place.

The only solution to creating true-procedural plants and environments is to manage, change, and make things unique after instancing. We should put a branch at its place and then the geonodes should look around and say: “Aha, this branch is at 77% of larger parent branch, witch is at 39% of trunk, and on the north side of the tree. That’s why this branch will have this shape.”

Please take a look at my question again. I edited it, and added your solution as example 4 with illustration and comments.

For now, I think the only way to make each branch unique is to use the realize instances node. The process is probably a bit different, but maybe it will work.
Eventually we'll have loop nodes and the whole thing might become a bit easier.

Sorry, previously i did not understood who you are. Now i know that you are one of developers of geometry nodes. I found your blog here https://code.blender.org/2021/09/procedural-curves-in-3-0-and-beyond/ and your giant work here https://developer.blender.org/p/HooglyBoogly/
Thank you so much for all that you have done for blender! A lot of blender stuff that I try now would not be possible without you! :)

Thanks! I'm glad you found something workable below :)


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Materials have gone weird after doing a "cell fracture" on my object
Hi everyone, I am sorry if this question has been asked somewhere else (I have looked at multiple forums to find an answer, but no luck yet).
I have a building that I added "Cell fracture" to. However, when I do, some of the cells have weird material changes. I have attached an image to explain this better.
My material is just a simple .png file.
Here is the link to the model that I have used.

Any help?
Thanks,
Josh

Hi, congrats on your first question here!  Some more info might be helpful, such as some details on the material (procedural, texture on a UV map, combo?), maybe a screenshot including the Shader Editor.  Also, it's sometimes a good idea to post your blend file, or a truncated version of it that has the problem.  Not sure about this time, but just so you know, the Blender StackExchange has its own service to share blend files:  https://blend-exchange.com/help

Thanks for the tips, I have edited my post :)

The issue seems to mainly be the model's UV mapping, although the trigon topology might also cause Cell Fracture some trouble:

The texture map is 256 pixels wide by 1 pixel tall, with the UV islands tiny spots.  When Cell Fracture makes new objects from a UV mapped source it makes a new UV map for each of them, and it's having trouble with this:

I'd recommended retopologizing and reworking the UV map of the building before using Cell Fracture on it.

Thanks for the reply. I am fairly new to blender, so I am not too sure what you mean by "retopologizing and reworking the UV map". Could you explain a bit further?
Thanks.

The topology and UV mapping of the model is common (and appropriate) for many games, but Blender's having trouble reading the tight coordinates of the UV map.  Googling on "UV Mapping" "Blender" should get you started, for more depth the Blender Manual is helpful:  https://docs.blender.org/manual/en/latest/modeling/meshes/uv/applying_image.html .  Once you have that fixed, if Cell Fracture gives you good results you shouldn't need to retopologize (change the structure of the mesh).  There's a 600 character limit on comments here, how much more detail do you need?

That should be good. I will try this when I get home and let you know how it goes.

Hope it helps!  If you need more info on UV unwrapping or retopologizing then searching this site, youtube, and/or forums like BlenderArtists should prove useful.  In the meantime, if I've answered your original question I'd appreciate it if you'd click the checkmark next to my answer.


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Image Texture not working
Hi everyone i dont know why my image Textures arent working
i tried to us this image texture
https://www.cgbookcase.com/textures/scratched-gold-01?source=textures.one
but it does not show up in any kind.
Besides from that i dont understand why my object is looking like plastic maybe someone can help me and give some tipps.
Thank you already

Have you modified your material to include the textures? Can you add a screenshot of your material nodes?

sure. what do you mean with modifying my material?

I meant that you've created a material that uses the textures (which you did). Have you switched to LookDev or Rendered viewport mode? Solid mode doesn't display any textures. Or does your material not show up in the rendered image (F12)? Then you probably haven't assigned the material to the  object.

the material shows up just not as displayed it looks simply golden

You mean it doesn't look like the preview on the website? It probably makes sense to add a texture coordinate node as well as a mapping node to your material. The scale for size of your texture might be off. Also make sure that you have proper lighting and something to reflect otherwise metal will look unrealistic (e.g. use an HDRI).

where should i add these 2 notes. Sorry im at the very beginning xD

Did you move the blend file or the images separately?


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Remove empty patches from quick fur effect
I would like to know if it is possible to remove these patches of empty space using the Quick Fur effect.

n here]3]3

What settings did you use? How does your mesh look like? Can you [edit] the question to add more details?

Thanks @Luciano... I have added the screens from the particles page :)


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Matrix rotation not changing scale
I'm trying to use Blender to test some matrix transforms but I'm still trying to learn at the same time.
The problem is how to use the Python API to apply a rotation matrix, but to start with I have tried this step.
First I added a Mesh Plane then Scaled it along Y axis so it forms a rectangle.
Running the code causes the plane to rotate but the shape is "restricted" by the scale of the shape before the transform. I expected the whole plane to rotate around the x-axis and keep the shape.
import mathutils
from mathutils import Matrix
from math import radians
import bpy

mat_rot = mathutils.Matrix.Rotation(radians(15.0), 4, 'X')

curr_obj = bpy.context.active_object
obj_mat = curr_obj.data
obj_mat.transform(Matrix(mat_rot))
obj_mat.update()

I also notice in the Properties Transform, the Rotation X does not change.
Can anyone help me understand what's going on?
UPDATE
lemon, thanks for info on using obj.matrix_world.
I have now tried this code now, but even the results are still not as expected. The shape doesn't keep the 6*6 square shape and the Rotation X is only 40.1deg instead of the 45deg.
Any ideas?
import mathutils
from mathutils import Matrix
from math import radians
import bpy

bpy.ops.mesh.primitive_plane_add(location=(0, 0, 0))
bpy.ops.transform.resize(value=(6, 6, 1))
obj = bpy.context.active_object
mat_rot = Matrix.Rotation(radians(45.0), 4, 'X')
obj.matrix_world = obj.matrix_world @ mat_rot

obj_mat.transform here changes the mesh vertices (at mesh level). Object transforms (at object level) are still applied after that. If you want to rotate at object level, you can obj.matrix_world = obj.matrix_world @ mat_rot

My bad I meant obj.matrix_world = mat_rot @ obj.matrix_world

In your second example, the shape changes, because your are transforming the mat_rot by the matrix_world, but you need to do it the other way around.
obj.matrix_world = mat_rot @ obj.matrix_world

Further, your code should be streamlined to apply the transformations at object level (and not through ops).
from mathutils import Matrix
from math import radians
import bpy

bpy.ops.mesh.primitive_plane_add(location=(0, 0, 0))

obj = bpy.context.active_object

mat_rot = Matrix.Rotation(radians(45.0), 4, 'X')
mat_sca_x = Matrix.Scale(6, 4, (1, 0, 0))

mat_sca_y = Matrix.Scale(6, 4, (0, 1, 0))
obj.matrix_world = mat_rot @ mat_sca_x @ mat_sca_y

And finally, you can rely on other methods than ops, to add your geometry. See this answer for details on adding geometry from scratch.
from mathutils import Matrix
from math import radians
import bpy
import bmesh

# Create the object and mesh datablock.
me = bpy.data.meshes.new("me")
obj = bpy.data.objects.new("obj", me)

# Apply the transformation.
mat_rot = Matrix.Rotation(radians(45.0), 4, 'X')
mat_sca = Matrix.Scale(6, 4)
obj.matrix_world = mat_rot @ mat_sca

# Add the grid as the mesh
bm = bmesh.new()
bmesh.ops.create_grid(bm, x_segments=1, y_segments=1, size=1)
bm.to_mesh(me)

# Link the object to the scene.
scene = bpy.context.scene
scene.collection.objects.link(obj)

Thank you, very good information for me!


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How do I make animations a steady speed?
When I make an animation, it always starts out slow, then speeds up, then slows down at the end.  I cannot figure out how to fix this.

Possibly related..

Simply go to the Animation Screen Layout:

Now select Channel > Extrapolation Mode > Linear Extrapolation (shortcut Shift + E):

And that should fix it for you.
If you look at the Graph Editor before doing this, you will see:

The beginning and end of the curve are levelled out, this is what gives you the slowing down effect. It is called a Bezier function. When you choose 'Linear Extrapolation' it makes the curve a straight line:

The straight line is extended in both directions giving you continued animation, whereby if you choose Interpolation, Key > Interpolation Mode > Linear (shortcut T):

What starts off as curves...

...results in straight lines between keyframes with no extension beyond:

Just as an addendum, you can change the extrapolation mode by pressing T on your keyboard.

Hitting T changes interpolation mode. Extrapolation mode means how the motion continues outside the keyframes.

How do I "go to the Animation Screen Layout"?

Go to the animation layout, and in the F-curve editor you can either hit T, to set the channel interpolation mode to linear, which affects the whole channel you have selected in the menu on the left side, or hit V to set the selected keyframe handles to vector mode. With setting single keyframe handles you have the possibility to use both kinds of interpolations.

Use a simple driver
For a constant linear animation can make a driver that is a linear function of frame.
For example to rotate an object about x at one revolution (2 * pi radians) per second in a scene with 24 fps, for ever...
Type the following
#2 * pi * frame / 24

directly into the X rotation euler channel.

.  The hash # prefix signifies to blender it is a driver expression.
Once entered it will turn purple (driver color) and can be edited directly (removing the hash)
The variables frame, the current frame,  and pi are known to the driver namespace.

Note this could ofcourse be reduced to
pi * frame / 12

I just changed extrapolation mode to Linear instead of Constant. Animation is now at a constant speed with no smoothing in/out.

How do I "change the extrapolation mode to Linear"?


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Blender game: How you can make an object to emit light?
In Blender Game how you can make an object to emit light? l known how you can make an object to emit light in Blender render but l don't known how you can make an object to emit light in Blender game.


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Obtain radiometric values from OpenEXR channels
Good morning everybody!
I created a physically accurate scene and my aim is to study radiometric conditions over the rendered scene in order to obtain an illumination map in terms of [W/m^2].
I saved images in OpenEXR file format, due to its high dynamic-range properties and I wanted to obtain a Relative Luminance Map starting from RGB values in "R" "G" "B" channels.
The major issue is how to scale linear values from OpenEXR channels to have physically accurate values between [0, 1], needed to obtain Relative Luminance map maintaining the HDR properties of the file format.
Part of the code is reported below.
'''
pt = Imath.PixelType(Imath.PixelType.FLOAT)
exrfile = exr.InputFile(filename)
dw = exrfile.header()['dataWindow']
size = (dw.max.x - dw.min.x + 1, dw.max.y - dw.min.y + 1)
redstr = exrfile.channel('R', pt)
red = np.fromstring(redstr, dtype = np.float32)
red.shape = (size[1], size[0]) # Numpy arrays are (row, col)

greenstr = exrfile.channel('G', pt)
green = np.fromstring(greenstr, dtype = np.float32)
green.shape = (size[1], size[0]) # Numpy arrays are (row, col)

bluestr = exrfile.channel('B', pt)
blue = np.fromstring(bluestr, dtype = np.float32)
blue.shape = (size[1], size[0]) # Numpy arrays are (row, col)

rel_luminance = 0.2126*red[:,:]+0.7152*green[:,:]+0.0722*blue[:,:]

For a test image the obtained Max values of the three channels are respectively:
Max(R) = 198.16421508789062
Max(G) = 173.5792999267578
Max(B) = 163.20120239257812
The obtained values are obviously not in the range between [0, 1], moreover I am not able to understand the global maximum value to scale the channels and obtain what i want.
Has someone some tips to solve my problem? Thanks in advance.


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Link BlackBody Shader node with blender python
I'm creating a physically accurate light on Blender to recreate the Sunlight for a spatial scene. I'm using python Blender and i cannot understand how to connect shader Nodes, in particular the blackbody one, to light model. I'm using the code reported below, but the result is a total white light, without any input of color due to the shader Node.
Thanks for your help!
bpy.ops.object.light_add(type='SUN', align='WORLD', location=(0, 0, 0), scale=(1, 1, 1))
bpy.context.active_object.name = SunLight["name"]

bpy.context.active_object.data.energy = SunLight["irradiance"]

bpy.context.active_object.data.angle = SunLight["angle"] / 57.2957795

bpy.context.active_object.rotation_euler = SunLight["rotation"]

bpy.context.active_object.data.use_nodes    = True
light                  = bpy.context.active_object.data
nodes                  = light.node_tree.nodes
lights_output          = nodes.get('Light Output')
lights_output.location = 0,    0
lights_output.width    = 180
node_ox                = nodes.get('Emission')
node_ox.location       = -200, 0
node_ox.width          = 180
links                  = light.node_tree.links
node_bb                = nodes.new(type="ShaderNodeBlackbody")
node_bb.inputs[0].default_value       = SunLight['temp']
node_bb.location       = -400, 0
node_bb.width          = 180
link                   = links.new(node_bb.outputs[0], node_ox.inputs[0])

I've seen that some others had obtained the wanted result with a similar code, but i can't understand the mistake.

Have a look into: Control Cycles/Eevee material nodes and material properties using python?
The emission node is created by default. All you really have to do is adding the blackbody node, set the properties and connect it using NodeLinks.new(): https://docs.blender.org/api/current/bpy.types.NodeTree.html?highlight=links#bpy.types.NodeTree.links

import bpy
import math

bpy.ops.object.light_add(type='SUN')
obj = bpy.context.active_object

# Sun properties
obj.data.energy = 1
obj.data.angle = math.radians(50)
obj.rotation_euler.x = math.radians(45.0)
obj.location.z = 2

# Nodes
obj.data.use_nodes = True
node_tree = obj.data.node_tree
nodes = node_tree.nodes
links = node_tree.links

# Default emission node
emit_node = nodes.get("Emission")
if emit_node:
    # Add blackbody node
    blackbody_node = nodes.new(type="ShaderNodeBlackbody")
    blackbody_node.location = (emit_node.location.x -200, emit_node.location.y)
    blackbody_node.inputs['Temperature'].default_value = 2300
    links.new(blackbody_node.outputs['Color'], emit_node.inputs['Color'])


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Geometry Nodes: allign object based on procedural geometry

Hello! I'm working on a Geometry Nodes procedural project, and I would like to improve something within the system: as simplified in the picture shown, I'm starting with a cube with some subdivision that is being displaced by some random textures. now, after the displacement, I want to "pick" the vertices that are the most far from each other, the most "opposite" vertices we could say, they could be anywhere in space after being displaced, and I want blender to "draw" a straight line between them , to use as an axis, and then I want to allign this line, this axis, with a world axis, say the world Y axis.
Basically, I want the object to be re-alligned with the world on the "longer" side is being created after being displaced.
Any ideas?

EDIT: AWESOME ANSWER by Robin Betts, that's great it works! the only issue now is that the line that is being created in order to allign the geometry is now perfectly in the center of the world axis, so the midpoint of the line become our new origin for the whole geometry, so the origin of the geometry is i little off... the result is awesome, just what I needed, but would there be a way to then "Set Origin" to the object volume, and offset the position, so that the center of volume is always alligned at world origin, while the line that we calculated remains parallel to choosen world axis?

Maybe a proper mathematician can come along and prove or refute this strategy. All I can say at the moment is that it's passing quite extreme tests, so far.

Take the convex hull. The extreme points must be in it, somewhere.
Find the furthest point from the mean of all points. (Pm)
From the remainder, find the furthest from Pm (Pm')
As requested, create a line between Pm and Pm' and transform the geometry such that its origin lies on the center of the line, and the line is oriented along an axis.

Above, makes a selection of the point(s) that are farthest from the mean position. Yes. We are hoping there's only one. But the possibility of a 'tie' is implicit in your question, not a problem with the solution.
Then the position of the point at that distance is derived:

A similar procedure follows for getting the furthest position from this one. A line is drawn between them. The whole is aligned as follows, where the incoming vectors are the ends of the line:

This is the result, on a not-very-random object:

Unless/until I think of a proof, I half expect this to get broken. Have a go, and see if you can.

Very interesting! I assumed a much more elaborate solution, but this looks really creative. ...Convex Hull, again :D

@quellenform   The Convex Hull is only to cut down the number of tests? Maybe that should be the median for the first test, not the mean (feels better, somehow) .. still trying to work out a proof, or break it...

Hi, @Jacopo .. thanks for the tick! I will improve this a bit..  a Field at Index (0)  to  get hold of extreme positions would behave better in the event of tied-distances than the Mean used here, I think.


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convert multiple lines(except surface) to tubes
I am working with an imported set of straight lines that came from a shapefile.
I want to convert all the lines(except surface) to tubes at once.
I find trans one line to one cube. When I select all the object and execute the opration,only one line be converted.
I know the python Scripting can help,but the code may be difficulty. I want to use the blender software to do it.

you can do it by

select all your objects

choose object -> convert to curve

you can see if an object is converted to curve in the outline. It has this symbol in front:

Now select all curve objects (don't select other objects)

click here:

ALT-Click in Depth:

enter value (or drag with mouse)

My blender version is 3.0.I do the same opration as you.Select all and the opration,but only the last can be change

Did you hold the CTRL key while clicking in Depth?

My bad. I try it,but it doesn't work.  ALT-Click works for me.

maybe my bad -> changed answer to ALT-click