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How to recover "three axis camera control" widget?
I'm sure it's an easy question, but I'm not sure what this thing is called to even look up the answer.
I made a custom Layout workflow tab that better suits me, and created a new Layout.001 workflow tab to recover the original default layout. Layout.001 is missing this little three-axis view angle control, though--how do I get it back? It's not the nub of an arrow you can see on the upper right; that just summons the N menus. I personally prefer hotkey, but if you know how to recover it from menus, that would be great for completeness. Thanks!
(PS is it possible to rename the workflow tabs?)

The name of the object in question is the Navigation Gizmo and the toggle checkbox for it is under the Gizmo menu (highlighted below):

I had simply hit the little "+" icon to create the workspace; nothing more. I think the layout came in without the widget by default. Thanks!
PS how did you resize the circles in your navigation widget? Edit > Preferences?

Hmm.. I'm not sure what you mean by "resize" - I don't think I altered the default values at all. Maybe it's because I'm using 3.0 alpha?

That might be it. I thought you'd simply adjusted various UI elements. Looks snazzy. Thanks for answering! (Incidentally, do you know if it's possible to rename workflow tabs, e.g. Layout, Modeling, Layout.001?)

Double click the name

Thanks! I swear I tried that before x)


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What happened to my "project/objects info" footer and how do I get it back?
I have no idea what I did or hit to get the footer info I usually see (e.g. # tris, edges, vertices, faces per visible project meshes or actively-edited mesh) to disappear. The screenshot was taken from my current project's Object mode; it currently only shows my version number, and this change persisted even after rebooting Blender. How do I get the footer back?

By default in 2.9 there'll be only Blender version afaik, as shown on the screenshot. You can enable those for previewing like explained in the linked answer

Thank you! I learned something with that linked answer. No idea when I unchecked the things in question, but now it's fixed!

Right click on the version number and check the options you're interested in.
You can have thoose infos in the 3d window overlays also, checking the "statistics" option.

Thank you! Exactly what I needed. (Linked answer has more, I see.)

source: Stack Exchange

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

sort: votes


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Why does Blender show trees in my glass cube?
What I’m trying to achieve is an glassy object. Therefore I’ve opened a new scene in Blender 2.82a. I’ve Enabled Screen Space Reflections in Render Properties and set “Shade Smooth” for the object. I’ve set Transmisson to 1, reduced Roughness to 0 and enabled Screen Space Refraction in Material Properties. I didn’t do anything else. Entering the Viewport Shading view I’m seeing this:

I’m afraid this is as newbie as it gets, but I’m stuck. I’ve dived into various settings for an hour or so and I’ve tried to google a solution for another without having any luck because I’ve no idea what’s happening and why. Why are there trees reflecting in my glass cube in an otherwise empty scene? And how do I get rid of them? I’ve found a place where I can change the image by clicking on the upper right downwards pointing arrow. But I’m unable to remove it or to replace it with a plain color or whatever. I’ve tried to enable ”Scene Lights“ and ”Scene World“ but that’s turning everything into anthracite leaving me literally groping in the dark.

You probably don't want "Shade Smooth."  It has nothing to do with whether the surface of your object is smooth(glossy) as opposed to rough. Shade Smooth averages the surface normal vectors over your mesh. In effect, when shade smooth is on, light interacts with the cube as if it were a sphere.

What exactly did you expect to see when you remove this image? The only thing you see when looking at a perfectly reflecting/refracting object is the surroundings.

Neither of these comments are helpful. I have the same issue with a glossy object in a scene populated with different objects and want what is around to be reflected, not pixelated ugly trees

The screen space reflections in Eevee especially with highly reflective materials, for example metal with 0 roughness or glass like yours, will always show the environment like a mirror.
In Material Preview (Eevee is used, even if Cycles is set as render engine), you have a few HDRIs to choose from and if no Background is set up manually, Blender will use it's preinstalled HDRIs.

The default one used is the 3rd one.
Those are only for convenience and not necessarily used for final results.
Also the place where you set your own world environment, be it a color or HDRI, is in the World Properties:

The easiest way to set up your own HDRI, is to go in the Shading tab and do the following:

Switch the mode to World

In the Shader Editor press Shift+A to add a new Environment Texture Node.

Connect the Color output of the new Node to the Color input of the Background Node.
Now you can load a HDRI in the new node. You can find free HDRIs online (HDRIHaven for example). Beware though, they are rather big files if you want good resolution.
Lastly if you have an HDRI loaded in, you want to turn the Scene World option in the Preview Mode on, so it will use your HDRI and not the default one anymore.

Here how it can look:

mind that i did not set the cube to glass
In case you just want a color, skip all the steps and directly in the World Properties the color field above the Strength can be used to change and adjust the color used for your scene. I'd advice though against using the pure color, as it really is nothing else then making the entire scene be in that one color.
Here how that can look:

There are a lot tutorials out there, worth watching, as there are so many features, that it can be overwhelming at the start.
Happy Blending

"Those are only for convenience" - introducing the most confusing and angering feature and making it enabled by default for thousands of newbie users

The preview you are in is called lookdev, which generates lights and reflections from a hidden HDRI image. If you want to see your model how it would look rendered, switch to rendered preview.

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


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How can i have different mass on same object?
So, I am building a project that has double pendulum, like one pendulum attached to another pendulum...
So i created a cylinder and scaled it up and made it like a thin long rod and then i added a sphere (while being in edit mode) and made a bob of pendulum, then i gave a rigid body simulation to it... i wanted the rod to have different mass and the bob tho have different mass. how can i do that?
Thank you..

Getting mass is easy.  You apply rigid body in physics menu then open the setting arrow in it. The default is 1kg but you can change this to particular materials eg lead in the object>rigid body>calculate mass menu option. This works well and I've built complex shapes using micro cubes like lego/mineworld and then hot their masses and simulated them.
I too would like advice on best approach to double pendulum. I tried 3 UV Sphere connected by nurb paths extending the many youtube  simple pendulum Blender examples.  I can only get the middle ball to swing and one nurb path just gets stuck locking the second pendulum.  Did you complete? I wish some guru would show how its best done...


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How to make characters hand/pass each other objects
I've been animating a scene and currently have a character holding an object using the child of constraint. Is there anyway I can make the character pass the object to another character (they use the same rig.) I don't see any tutorials online so coming here seemed like a good idea. Thanks!

you could do it the hard way, meaning keyframing the Visual LocRotScale of the object, but there's an addon called Dynamic Parent that should work for 2.8, explained here: https://www.youtube.com/watch?v=YoXz4IKpoq8   the code is here but I don't know how you import it into Blender: https://raw.githubusercontent.com/romanvolodin/dynamic_parent/2.8/dynamic_parent.py

And I answered in details here, hope this helps: https://blender.stackexchange.com/questions/179852/how-to-switch-the-objects-parent-from-one-bone-to-another

In the same way that you've already created a Child Of constraint for the first character, you can simply create another Child Of constraint for the second character, and point it to the same object as a target. Only, the second character's Child Of constraint should have its influence slider set to zero, and keyframed at zero for whatever length of time that the first character is to have the object in hand. Likewise, the first character should have the Influence slider for its own Child Of constraint set to be fully active, and also keyframed as such, for that same duration. At the time that the hand-off happens, you simply keyframe the influence of both Child Of constraints to have reverse influence from what they both had one single frame beforehand. This works very well. The two characters do not even have to have anything in common regarding their rigs. They certainly don't need to have rigs that are exact copies of one another. They simply each need their own Child Of constraint, and each of them needs to point to the same object. The only thing that changes is the influence.


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How Can I Keep Blender From Remembering Bad File Paths?
I was installing Diffeomorphic and foolishly installed Dropbox in the process. This somehow convince Blender that dropbox is the location for all my files. I got rid of drop box, but I can't convince Blender to use the file paths on my C: drive, or erase dropbox paths from its lists for importing and exporting, so these operations keep failing.
I uninstalled Blender and reinstalled it, but it preserved its memory of bad paths.
How can I fix this?

If you are referring to the "Recent Locations" in the Blender File View, there is a button to reset the recent file locations.

That's helpful, but not quite what I was after. In the top bar of this window there's an address bar for where Blender will start looking for things. Clearing the 'recent' window lower left doesn't change this, and this is stuck on a non-existent path. Further, if I manually edit the path, it seems unable to find any folders in that location. If I browse through the tree under the 'system' tab upper left, it also ignores all the folders on the desktop, adds 'dropbox' back into the path, and goes into 'not responding' mode if I try to import an object anyway.

Hm...have you tried reinstalling Blender then?

There's just plain gotta be a file or path in the User Pref's that's doing that.  Have you looked in your c:\Users --> Application_data folder(s) to see what's in there under "Blender Foundation" or similar?  Your user pref's file is also stored there.  Have you more than one user in your PC?  If so, check them all.  You might also try a file search for 'Blender', 'Config', etc.
Sorry to be a little vague.  I'm not on a Windows machine at present.

Thanks. I'll explore those places- I just had no idea where to start.

Um... can't find these folders. Could you please provide a complete path example?
I uninstalled Blender, searched the whole disk for 'blender' and removed anything that seemed able to hold such data (and a lot more...), reinstalled blender, and it still likes these Dropbox paths. I can't find where these are stored!

The AppData folder is a hidden folder in Windows by default, so you won't be able to view it just by looking for it without enabling "Show Hidden Files and Folders". You can try opening Windows start menu, search for "Run", open that program, then enter %appdata%

Current Status:  "Dropbox" is gone from system, but Blender still defaults to file path with dropbox in Import Window. Rest to Default allows to navigate to real file path, but this is forgotten on next opening of window.
I used run -> appdata to navigate to Blender config file. I found three text files, one of which had a 'dropbox' file path in it. I removed this. Blender STILL uses this path as default file path. HOW CAN I STOP THIS?!?!? This is just crazy, and very time consuming.

Try opening a new file, resetting the file path as you did above, then going to File > Defaults >  Save Startup File

Well, I used Show Hidden Files and found MORE disguised dropbox locations, fixed them, and now Blender doesn't use them. However, the Import Window now defaults to my documents folder. I tried to set a path and use Save Startup File but this does not have any effect.


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move an object in custom direction using blender API
My greetings to the community.
I have a specific task which i have managed to perform using python. I need to do the same task faster and i believe i found a way but i need some help with that. My problem is the lack of understanding of the problem in 3d-space and more specifically the matrix transformations in local/global coordinates.
I have an object which i need to move in a specific direction by 1cm in local coordinates.
the lower object in the figure is the original position and the upper is the target position. therefoer the movement is towards Z in local coordinates.

What i do is:
new_location = Vector((0, 0, 1)) # move by 1cm in the Z-direction
trans = Matrix.Translation(new_location)  # create transformation matrix
object.matrix_world @= trans
mat = object.matrix_world
verts = [mat @ v.co for v in object.data.vertices]

This works just fine but it is slow due to the translation of each vertice in the last loop.
I think i can do the same (correct me if i'm wrong) using bpy.ops.transform.translate. something like this:
bpy.ops.transform.translate(value=(0, 0, 1), orient_type='LOCAL',
                            orient_matrix=((1, 0, 0), (0, 1, 0), (0, 1, 0)), orient_matrix_type='LOCAL',
                            mirror=True, use_proportional_edit=False, proportional_edit_falloff='SMOOTH',
                            proportional_size=1, use_proportional_connected=False,
                            use_proportional_projected=False, release_confirm=True)

but what i can't figure out the correct values of "value" and "orient_matrix".
thanks in advance

The gist of this is pretty much https://blender.stackexchange.com/questions/139511/replace-matrix-vector-list-comprehensions-with-something-more-efficient

yes that worked, thanks


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Why is the object not moving along the curve path?
Yet again, I am have problem with the curve-modifier. So I did exactly (or at least I believe I did) as what others told me in my last question:
set origin of the curve to its geometry > set cursor to the curve > set origin of the tube to its geometry > move the tube to the cursor
And then I applied the curve-modifier and move it along the Z-axis. But for some reason, the tube ran out of the curve and they were not aligned any more. The same happened to the cylinder array that is supposed to run along the curve as well. I tried rotating the tube and change the axis, but it still didn't work.
Could anyone please point out what I missed in these steps? The file is attached as follows: the tube and cylin_array are the application of curve modifier, whereas the tube.001 and cylin_array.001 are after the application.

hello, there are 4 objects, which one do you want to follow the curve?

Thanks for your comment. I'd like both "tube" and "cylin_array" to follow the curve. The "tube.001" and "cylin_array.001" is an example of what I am having now after applying the curve modifier.

What you need to do when you want an object to correctly follow the curve is to put both the curve and the object origin at the exact same place. So here:

Select the curve, press ShiftS > Cursor to Selected
Select the object (for example tube) and press ShiftS > Selection to Cursor
Give your object a Curve modifier, find the right Deform Axis (here -Z)
The object is a bit shifted, it's because you've rotated it and didn't apply the rotation, you need to apply (ShiftA)
If you want the curve to go in the opposite direction, switch to Edit mode, right click and Switch Direction

Thanks so much for your help. I have no idea why a rotation was (not) applied to my curve. Where/what should I check to prevent similar situations from happening?

You can't really prevent that, if you really don't want an object to rotate you can lock its rotation value in the N panel but anyway when you use array along curve you always need to check few things to make sure that it will work correctly, like applying the transform (make sure that the handle radius are set at 1 in the N panel though), checking the normal directions, match the origins, etc...


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What is the key for the curve modifier to work properly?
I created a snail-shaped curve using Bezier curve, and a straight tube using BMesh. I hope to deform the shape of the tube, so that its long axis follows the path of the curve, but the modifer does not give me the right outcome, no matter which axis I chose (neither did the translation work). Is there anything I missed? What is the key for it to function properly?
The file is attached here:

It will simplify if you set the origin of both your objects to their geometry (right click and Set Origin to Geometry)
Once done, put the 2 objects at the same location (select one object, press ShiftS > Cursor to Selected, select the other object and ShiftS > Selection to Cursor)
Create some edge loops all along your tube if you want it to bend
Give it the Curve modifier with the curve as Object

Thanks very much for your response! It worked! Now I just need to find a way to script it so that it can be more efficient in future because I may need to do it quite often.

Your object needs to be subdivided down its length to be deformed by the curve. The Curve modifier does not generate vertices, it can only move them about, and 2 vertices will always be joined by a straight edge.
Beyond that, you might want to follow the steps in this recent answer. Your scales are OK, but the other steps may help you out.
BUT...
The main point of this answer is to suggest that you may not need to deform an object down this curve at all. If your profile is circular, you can use the curve's native Bevel, accessible through its Data tab > Geometry panel. The curve can generate the circular geometry by itself, and you can convert it to a mesh whenever you like.
If you need to change the profile's radius on the way down the curve, you can AltS scale the profile at any control point. In the  Active Spline panel, you can change the way the radius is interpolated between control points.

Thanks so much for your response! Yes I know about increasing the bevel to convert it into tube: I added a bit of depth to the curve so that I could see it more clearly. The problem is: 1) I am not sure how large the depth represent, so example I added 10 mm to the curve (assuming my dimension setting was correct), but it was still barely visible; in comparison, my tube was supposed to be 0.18 mm and it was already way thicker 2) I also need to create patches around the tube to be bent along the curve as well. Therefore, I thought using a curve modifier for them would be more feasible.

@yggthir   There are two ways, apart from modifiers, that the radius of the tube might not be the measurement displayed in the Geometry > Bevel > Depth field: Object-Level Scale, and the per-Control-Point (Edit mode)  Radius. Both are multipliers of 'Depth'. You can always convert the curve to a mesh for further editing.. e.g  duplicating parts of the surface to make features.


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Does the "diameter" in "bmesh.ops.create_uvsphere" actually mean "radius"?
I created a sphere using
bmesh.ops.create_uvsphere(bm, u_segments=32, v_segments=16, diameter=1)

but later I noticed the radius of the sphere was 1 grid. As the exact size of the sphere was very important to me, I decided to check if 1 grid side is actually 0.5 (with whatever unit), but I didn't find anything particular. Afterwards I use the GUI way i.e. SHIFT+A to create a standard sphere (which should mean the size aka radius is 1), and I found they were exactly the same size.... So my question is: does the diameter in bmesh.ops.create_uvsphere actually mean radius, or am I missing something here?
P.S. I tried searching in the documentation but didn't find anything regarding this, so I decided to post the question here. I hope it is nothing too stupid.

IIRC it was a diameter, and was changed to  a radius to  be more consistent, however the argument name was not changed, to avoid breaking scripts..  https://developer.blender.org/T52923

Cool! Thank you for your reply! I was trying create_cone and found the same situation so I was wondering if it was a universal thing.


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Whenever I run my cloth simulation, the cloth collides with the 'static' pose of my character, and not the animated poses of that character
I have a very low poly character who I have animated to 'sit up' and then move to a pose. I am running a cloth simulation to drop a poncho from out of frame onto the character. The cloth will collide and interact with the 'default' pose of the character, ie how the character stands in edit mode, but will not collide or interact with the character in pose mode. I have attached two photos to demonstrate this, the first is the pose that the cloth should be colliding with and the second is the 'default' pose that the cloth is actually colliding with. I am very new to blender, so you may have to talk to me like I am a 5-year-old!

Look on the modifier stack (select character, properties/modifiers.)  Move the collision modifier to the end (bottom) of the stack.

Thanks! Didn't realize the collision would apply to the initial pose before the armature movement if the collision was on top of the stack. Makes sense and works now!

Thanks to Nathan for the answer!
My modifier stack had the collision on top, which messed with the simulation. I moved the collision to the bottom of the stack and the issue was fixed.

Feel free to accept your own answer, and that will close the loop on this question.

@AllenSimpson Thank you for the reminder.


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How do I assign a colour to this part only
I need to assign a color to this part:

But when I assign it, this happens:

How do I make it go only in the selected area?
heres the full image if it helps:

Your Subdivision Surface modifier will deform the shape of your faces and therefore the shape of your moon. You'd better use a PNG image as a mask in your material:

If you don't want to use this method I guess you need to work the topology until it gives the desired result (you can use a copy of your object as the target of a Shrinkwrap modifier so that the shape stays the same):

Thanks for replying, I would but I need to follow the concept exactly, and I would just mess up the mask

Welcome to BSE,
You appear to have overlapping faces. The faces to which you are attempting to add color are overlapping with other faces from your model.
If you can provide you .blend file I can provide more advice on how to fix this, but for now I would suggest introducing a separate mesh into your model (i.e. Shift+A > Mesh > UV Sphere), and apply the new color to the new mesh.

I have no idea how to do the separate mesh method
So um how do I provide the file? Or how do I do the separate mesh?

Nevermind, one of my friends told me just to apply the modifier and it worked!


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How do I remove a vertex without affecting other edges and faces?
I need to remove the moon shape made by vertices:
But when I delete, the faces and edges remove
And when I dissolve, the edges get destroyed:
I need all of those edges (and faces), but I have no idea how to do it without affecting other things

Select the bad edges (in Edge Select mode) and press Ctrl X to dissolve

In Edit Mode:

Switch to Edge-Select Mode (yellow circle in the screenshot)
Select only the edges you want to have removed (click on one, then hold down Shift key to select more)
When all edges you want to remove are seleceted, hit X on keyboard to delete
a context menu will open up: Click "Dissolve Edges" to dissolve, not delete them


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Python: Keyframe points not being deleted
I am trying to go through keyframes and delete unnecessary intermediate ones. Here is what I've written. I do not need it to be efficient I just need it to work ASAP so that I can use my add-on for work that I need to get done.
I started with this:
    for fc in l.animation_data.action.fcurves:
        i = 2
        while i < len(fc.keyframe_points):
            kp1 = fc.keyframe_points[i-2]
            kp2 = fc.keyframe_points[i-1]
            kp3 = fc.keyframe_points[i]
            if kp1.co[1] == kp2.co[1] == kp3.co[1]:
                fc.keyframe_points.remove(kp2)
            i+=1

After that didnt work, I assumed that maybe fc wasn't the original fcurve and was isntead a copy, and so was not being properly updated. I thought that this would fix it, but it's still not working.
    l = bpy.data.objects[fix.attrib['name']].data
    for j in range(len(l.animation_data.action.fcurves)):
        fc = l.animation_data.action.fcurves[j]
        i = 2
        while i < len(fc.keyframe_points):
            kp1 = fc.keyframe_points[i-2]
            kp2 = fc.keyframe_points[i-1]
            kp3 = fc.keyframe_points[i]
            if kp1.co[1] == kp2.co[1] == kp3.co[1]:
                l.animation_data.action.fcurves[j].keyframe_points.remove(kp2)
            i+=1

Debugging tells me that it does reach into that if statement, just that AFAIK the next statement isn't doing anything. Any advice?

fc isn't a copy. Shouldn't you not increment i when you remove a point, since all the ones after it shift over one?

@scurest That's what I thoguht about fc, but it didn't works so that was my next guess.
WRONG I think incrementing is right, because I am deleting the middle one, not the latest one. WRONG
Nevermind. I ran through it in my head and see the issue

@scurest formatting edited comments is hard. I put the increment into an else statement and it works perfectly. I think I just had so many extraneous keyframes that I didn't realize I WAS deleting some of them. Thanks for the help.


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How do I merge two armature ends into one?
I want to merge the armature joint to the other bone joint located at the 3D cursor.
I will also move the first joint onto the 3D cursor but how can I merge the two into one single joint at the 3D cursor?
I am using a metarig and learning all of this for the first time and I can see a dotted line between the two joints and I do not know what that technically means. But thought I'd mention it in case that is something that can help with the answer to this problem.

Hello and welcome. Are both bones you want to connect together part of the same armature? If they are part of the same armature you first select the bone with the tail you want to connect (left bone in your pic) then Shift+Click the bone with the head you want to connect (right bone in your pic) then press Ctrl+P > Connected

Oh 2 armature ends you said in your post. So you don't want to join the armatures with Ctrl+J? They have to be separate armatures?

Snap bone to cursor:

Select both armatures > Editmode > Select bone tail
Armature > Snap > Selection to Cursor

Snap bone with active tool to targets:

Select both armatures > Editmode
Drag: Active Tool > PivotPoint: Active Element > Enable Snap > SnapTo: Vertex
Select bone tail and pull to target


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Mesh shading problem with shade smooth
I've created a pile of firewood using rigid bodies. However, upon shading it smooth (and turning on auto smooth), the meshes' shading go problematic.

I have tried recalculating the normals but that didn't work out. One user suggested separating one object from the mesh and then rejoining it (didn't work).
Does anybody know why this problem occurs? And if there's any ways I can fix this.
Thank you.

Apply the scale and it will work correctly (not sure why it messes up the shading though)

Looks like that's the answer. So simple! Thank you!


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Render Quality Doesn't Change
this my first time modeling a object from scratch. im using blender's latest version on steam. but i have a problem about render image. whatever I do the render quilty isn't changing. i increased samples, added denoise etc but it didn't effect anything. it always has a weird fuzziness on it. (and the second problem i discovered the rendered image in viewport looking much better.) what should i do?

I don’t think that’s a render problem per se. It appears to be intentional displacement on the bottle from a texture, or possibly systematically bad geometry. Zoom in on it and see if it stays the same size. Show a wireframe, and see if it lines up with anything. Swap materials around, and see if it changes.

You say it’s invisible in the viewport. Are you sure you’re in viewpoint render, or just material preview?

nope i don't think so. bcause the bottle has a label on it and it pixelated too

To me, that looks like Z-fighting. Any chance you have a second object that is hidden in the viewport? Objects hidden in the viewport will still be visible in renders unless they are disabled.

If you want a solution to your problem, you could provide a blend file on https://blend-exchange.com/ so we can figure it out. The image and description alone may not be enough for us to identify the cause.

@ChristopherBennett Thank you so much! Its fixed now, I wish I knew it was that easy! I didn't know blender renders hidden objects. I was created a backup mesh of my bottle and it turns out it is the reason of overlapping.

@UtkuB. Glad it's fixed :). if no one else has posted this as an answer for you, when some  time  has passed, you can answer your own post and mark it as accepted, to clear it up


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Heat Weighting: Failed to find solution for one or more bones - Already Tried Merging
Already tried Merge by Distance and it didn't work. I had it working at some point but deleted armature and restarted due to some errors. Can someone help me find my issue, I don't want to recreate the mesh. I'd prefer to use the mesh I have now. Thanks!
Project File

For me, this has typically been because the mesh has disconnected pieces. Consider making them separate objects.

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.

Does this answer your question? Heat Weighting: Failed to find solution for one or more bones

You need to apply the scale of the armature and object with CtrlA. Unparent the object with AltP. In Edit mode recalculate the normals of your object as they are flipped with ShiftN. Merge by Distance to remove the overlapping vertices with M. It still doesn't work because the mesh is a bit too dense, so increase the scale of both the armature and object (like x 5), parent With Automatic Weight, then bring them back to 1:1:1.

This worked thank you very much moonboots you are a legend


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How can I get the value of a property at a specific key frame?
I have a pretty basic scene where a light's power goes from 3000 to 0, keyframed at frame 0 and 80. How can I use python to retrieve the value of the 'Power' property at any specific frame?
I know I can access the object's power by using
power = obj.data.energy

but I don't know how I can make that dependent on a specific frame.
Thanks

The easiest way is to change to the desired frame and access the property normally.
frame = 24
bpy.context.scene.frame_set(frame)
power = obj.data.energy  # value on frame 24


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Color sliders on vertical color bar rapidly scale from 0 to 40 instead of normally 0 to 1.0, how to fix this?
for example, adjusting the color sliders on a point source light, you can use use the horizontal slider fine, but on the vertical color picker, it shoots from 0 to 40 and doesn't preview any colors except white on the bar. How can I fix the behavior to normal again where I can see a color gradient on it with values properly scaling from 0 to 1.0? Attached example

What Blender version is that? - I've never seen that happen on a color picker so it may be a bug. Also, where has the outlined "C" come from on the R/H end of the color bar below the picker? I've never seen that either.

This is K-Cycles build of Blender, 3.2. Slider always worked properly until I guess some addons recently. I'm trying to figure out what changed and how to fix it.

TLDR: The answer
I guess the answer to your specific question is simply... Decrease the value by either dragging or clicking and typing, to a value within the $[0..1]$ range. I know, you can't go back in time and un-see it, the world will never be the same now.
Blender values have two types of limits

Hard limits - if you input something above the maximum, it will be set to that maximum instead; if you input something below the minimum, it will be set to that minimum; it's called clamping:

Soft limits - these can't go beyond the hard limits. When you use your mouse to change the value, and the value is within the soft limits, dragging the value or clicking on arrow buttons, will not allow you to go beyond those limits. However, you can still type a value beyond the soft limit. Once you do, and end up outside the soft limits, you can now use your mouse to increase the value further above the soft limit (so the soft limit is like a single boundary, once crossed, the mouse is no longer constrained):

Notice how once you're above the maximum soft limit, you still can't drag the value below the minimum soft limit, because you would have to cross the boundary. However, you can go back and pass the maximum soft limit, because Blender remembers you started dragging beyond the maximum soft limit, and allows the mouse to restore the starting value.
Another interesting thing about soft limits is that for many fields they adjust automatically: for example color values are constrained to:

$[0..1]$ range

but once you go slightly above that, e.g. $1.1$, they become constrained to

$[0..2]$ range

with the next soft value ranges being:

$[0..5]$
$[0..10]$
$[0..20]$
$[0..50]$
$[0..100]$
$[0..200]$
$[0..500]$
$[0..1000]$
$[0..2000]$
$[0..5000]$

...And so on, it seems to follow a pattern typical for coin/banknote values.
Not everyone knows, color values in shaders are simply arrays of 3 float32 values, just like vectors. This means that each RGB color component can have any value in range:
$$-3.4028235e+38 .. +3.4028235e+38$$
or between $-340282349999999991754788743781432688640$ and $+340282349999999991754788743781432688640$
Though those min and max values will (incorrectly) display as -inf and +inf.
Additionally, color inputs will not allow you to input values below 0 - so the minimum hard limit is 0, but only for the inputs - the colors can still use negative values, you just need use a any other socket type, that doesn't have this limitation, and connect it via a link:

The above setup will produce a material that will absorb more red light than what the material settings (default specularity) allow. The animation below shows how an object with specularity 0.5 can become darker than black, and how some values will produce glitches in the form of very bright edges:

In general, color values outside of the $[0..1]$ range are strongly discouraged in realistic rendering, because such values in physical terms mean that the material bounces more light than it receives (or absorbs more light than it receives - in case of negative values) - it breaks the conservation of energy. However, for non-photorealistic rendering and just for dirty hacks, a common example of a value above 1 for color is $16.19$, which is required in Filmic color space to produce a full white #FFFFFF color. Let's set this cube's left side to $(1, 1, 1)$, and right side to $(16.19, 16.19, 16.19)$:

Pure white background + filmic + antialiasing: is it possible?


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Animating a spring in a unity compatible way
I want to model and animate a spring in blender. But my animation seems not to be compatible with unity.
What I tried so far:
Curve

Created a curve and added volume to it
Added a Bone
Mapped the bone to the curve with Hooks
Animated via key frames

The Problem with this is, that it works perfectly in blender, but unity just ignores the animation. You can see the bone, but the spring stays still.
Curve to mesh

Created a curve and added volume to it
Converted to mesh
Added a Bone with parenting
Animated via keyframes

The problem with this is that it distorts the thickness of the spring instead of just lowering the space between the rings. But the animation does import correctly to unity.

(Curve left, Curve to mesh right)
Is there any way to animate a spring like shape without distorting the mesh too much, which is compatible with the latest version of unity?

Use a Shape Key instead of an Armature to animate the spring. Shape Keys are exported to Unity via FBX, and are called Blend Shapes.
For Blender 3.4 and and above replace the Z-Up Curve Tilt node with a Set Curve Normal node with Mode set to Z Up
You can use Geometry Nodes to create the spring in Blender. Here is a Node Setup:

The Z-Up Curve Tilt is a group (no longer needed in Blender 3.4 and above):

I got it here from blenderartist Zeroskill
The input parameters of the modifiers will look like this:

You can adjust these until you are happy with your spring, then test the Spiral Height value for what you would like your spring to look like in the compressed state and set this value in the Spiral Compressed Height. The Spiral Height and Spiral Compressed Height should be different, and you wont see the effect of the Spiral Compressed Height until later.
Now apply the modifier. Then, in the Object Data Properties look for Attributes. You should find an Attribute called "compressed_pos". This has been generated by the Geometry Nodes setup.

You will need to convert this Attribute to a Shape Key. You can do that by selecting it and then running this script:
script to convert an attribute to a shape key
You should then get a Basis and a compressed_pos Shape key.

The Model can now be exported as FBX and animated with Blend Shapes in Unity


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Text mesh topology problem, with overlapping characters
I know that there are several solutions for fixing the topology of meshes that are converted from text. However, the font I'm using is Segoe Script regular, which is a cursive typeface. The key issue is that the characters overlap where one character flows into the next, and when converted to a mesh this creates a problem. The characters are overlapping but the whole piece of text is one object. An example of what it looks like is attached: . The problem comes when you try to do something such as add a rim to the font: The characters are in an inbetween state, half separate objects and half the same object, and I have been unable to find a way to clean up the mesh so that linked characters are properly joined together.These overlapping objects within a single object also create a problem within cycles which doesn't render them cleanly either.
I've tried using remesh but that doesn't work. Does anyone have an idea? I'm relatively inexperienced at using Blender.
Thanks

What does it give if you select one letter (press L to select a separate mesh), then Ctrl F > Intersect (Boolean)? You then need to choose Union in the Operator box (panel on the bottom left of the 3D view)

If Boolean would not working for you ...

take a black&white screenshot of your text

drag& drop into viewport (it became Empty object)
search Trace Image to Grease Pencil

Search Convert Grease Pencil > Mesh
Fill Alt+F
Add Solidify modifier

Alternatively you can use Delete > Limited Disolve to merge faces into N-gons

and use like Face Inset and Extrude outline ... or what ever.

Thanks for this. I subsequently found some adjustments I could make that essentially obfuscated rather than resolved the problem, but if I ever need to do it properly, this looks like a great solution to me.


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How do I add audio to a single animated action in Blender?
I have animated an action using the action editor, but I want audio to play during that specific action. I could not find any useful tutorials explaining this online, how would I go about this?

To add audio to the animation you can use the sequence editor, in the N panel you can activate the sound waves for a better visualization.

You can also enable audio scrubbing and audio sync to hear the audio along with the animation.

Thank you. However, whenever I switch to a different action, the audio still plays. Can I assign the audio to only play during that certain action?

You can't assign an audio to an action, but you can add each audio in a channel and rename the channels, and when you change action you just disable all channels except the current action. Screenshoot


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Blender 3.x screw across uneven cylinder
So I've been following along at https://www.youtube.com/watch?v=Ys_8P9Et28I to make a leather handle for my war hammer. However, my model has a handle which tapers which means the geo get's a bit skewiffed. Does anyone know how to get the screw modifier to work in cases where the geo it's wrapping around isn't regular shaped?

It might be helpful to people trying to help you if you attached an image of what you have,  or upload an example blend file to the site https://blend-exchange.giantcowfilms.com/ and add that link in the question.

This isn't so much an answer as an example workflow for a one-off.. plenty of other ways would be just as good, I'm sure..
This case is deliberately a bit awkward.. non-circular profile, varying diameters, curved shaft...

The general process is to work up and down a modifier stack, sometimes tweaking the mesh, and earlier modifiers, to work well with later ones. The modifiers are introduced one at a time, always feeling free to go back and adjust, viewing the result through the whole stack.

The unmodified mesh is a single, subdivided line of vertices. (It started out even and vertical, but was rotated and adjusted later, while viewing under the influence of later modifiers)
A straight Screw modifier
A Simple Deform > Taper
An edge-loop was duplicated from the handle , converted to a curve, and used as the basis for a Curve modifier. The idea of steps 3 and 4 is to give Shrinkwrap a helping hand; to have it project in reasonable directions.
Shrinkwrap, 'Target Normal Project', 'Above Surface'. The Shrinkwrap is aimed at a vertex-group. the weights of the vertices in the original line were tweaked to make the shrink more or less tight. In this case, making the shrink looser on the second vertex down gives a hint of the tape going under itself. The weights give very fine control on the shrink.
Smooth, Solidify, Bevel, Subdivision Surface modifiers..

with this result:

( ...Maybe too clean.. maybe a noisy Displace in Z just after the Screw would be good :) )
The point of this is not to recommend the particular modifiers used, but to suggest the workflow : modelling under modifiers, working backwards and forwards, tweaking them up and down the stack.


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Arms move in wrong direction while legs are fine
My model's arms bend backwards at the elbow when moving them toward the back of the character, but my legs act perfectly normally.
The only guides I've seen that seem like they might have the solution only talk about setting up a controller bone for the legs, not arms, and I can't figure out how to translate that to arms - but I'm using Rigify anyway, and the guides seem to be using the armature by itself(?) so I don't think controller bones are what I need as I'm not animating using the armature...?
One guide suggested that it was down to not placing a bend in the limb before generating, so I started over and tried placing a bend in the elbow in the natural direction, generated a new rig, but still had the same issue.
My legs work great but the arms just won't cooperate for some reason. I would use the FK bones(?) and just snap to those, but they twist my mesh when posed + also don't pull the mesh with them when moved - acting like objects that aren't parented - so you can only see what you've done after placing them and snapping to them which is less than optimal.

I've tried to follow any guide I can to fix the issues and make sure I'm using everything correctly, but I'm either not finding things I need, or getting confused by them when I do.
I've considered just not using rigify, but I'm new at this, and I don't know what the best course is that fits what I want to do. I've heard that rigify can be super useful and a good way to do things, but I've also heard of people using other methods and never touching rigify - but I don't know how they compare or what to go with based on my needs, so I've just been trying to make it work for now.
youtube video of issue

to be honest...if you are new...i would start using very simple rigs with two or four bones max to test and find out how it works. I wouldn't start with a human rig and i wouldn't start with an add-on if you don't know the basics at all. Why? because rigging is not intuitive and for sure not an easy topic. Of course you can start with bigger projects - but this could become frustrating....

If your rig also has "pole" bones (targets); those are the one used to control which way an elbow or knee bends when adjusting the IK for that part of the body.  In pose mode, review the bones that are incorrectly twisting, and look for a Bone Constraint IK that points to a target bone or Pole bone (the technique varies on the Rigging used) -- adjust that bone and the "twist" should correct.  If none of the problem bones has an IK or Pole target; add one.

Thanks. I'll try this stuff out and let you know how I do.
How should I go about adding a pole bone for the elbow?

Rigify already has a pole target. It's hidden by default. There is a switch in the Rigify Main Properties section in the N-panel named "Toggle Pole" (0/1). Select the "upper_arm.IK" control bone (the big red arrow) and you should see the switch. But usually, you don't need the pole target because you can use the arrow control to rotate the upper arm. If you bend the elbow of the metarig slightly it should work out of the box => https://i.sstatic.net/3yv02.gif -- Maybe post a screenshot of your metarig or share the file.

@Blunder thanks! I managed to get it to work. I don't know what I missed when I tried redoing the rig before. In moving the elbows back, though, the bones ended up a little further back than I feel they would be IRL - do you know if there's any limit to avoid there? Like, "stay inside the mesh", perhaps? Also is it good to put bends in the mesh as well, or should that be straight and the bend only in the bones?
For anyone else having issues reading this - just to clarify and make things easy - I used edit mode to move the metarig's elbows back and generated a new rigify rig. Fixed.

*realised I moved them a bit far back because I had x axis mirror on and I was trying to do them individually, so I ended up moving both twice as far.

Hey, glad it's working for you. Yes, sometimes the bones can be a little misaligned compared to IRL, especially when the character is in T-pose. But usually, the rig tolerates this. An A-pose, on the other hand, is a more natural pose & the bones can better follow the mesh. Of course, you can adjust the mesh to get a better alignment. The bones just must not stick out of the mesh because the Automatic Weights don't like this. I recently had a model where I had to adjust the legs slightly because the bones stuck out of the knees & the calculated weights were really bad. The adjustment fixed it.


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Ignoring vertices of a meshgrid outside UV map
What I want to do is to make field of holes in a curved mesh. Using geometry nodes I make a UV map of the mesh that is supposed to have holes in it. Then I make a meshgrid of various size and number of vertices so I can change the density of holes easily. Then I "fit" the mesh on the UV map and put instances on vertices of the meshgrid and align the instances. Then using Boolean difference I make holes in the mesh using these instances. Geometry nodes look like this.

It works quite well. The only problem is that the vertices of meshgrid that are outside the UV map transfer to the nearest face so on the edge of mesh there are many vertices I would like to ignore or delete because it makes mess. It looks like this.

As you can see it works but the edges are gathering the points outside the UV map and it makes this mess. Do you have any idea how to ignore or delete these vertices ? I don't want to do it manually. Thank you for any idea.

You can use the Geometry proximity node to get the distance between UV coordinate and spawned cylinder. And use selection input socket to prevent spawning cylinder if this distance is lager than 0

Works like charm ! Thank you very much !


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Animated Texture Over all the Existing Materials
I'm wondering if there is an option or a possibility to make a material that overlays or combines  all the existing materials without having to assign the whole UV map to it because if I do it will disconnect my already made materials from its UV maps. My goal is: I'm trying to make a reveal animation of the hoodie, from completely transparent to fully visible by using some type of texture in my case magic texture with colorramp. Currently this reveal animation is on the front of the hoodie and front part(UV's) are assigned to this material. How do I add this animation to the whole hoodie? with keeping the existing materials assigned to its UV's.
How do I assign this setup of nodes that are in the white box to the whole hoodie without disturbing the rest of the materials? is there a way to do so?

Hello do you have a video that shows what you want? or a storyboard?

@moonboots Hey, sure here is a link [https://drive.google.com/drive/folders/17mVRwgRD376Pp6avIrKwsYtb4dwi6Zdz?usp=sharing] I would like this reveal effect to affect the whole hoodie, according to my mains posts description


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i made a bench with 15 rectangles intersecting each other and painted it, only 1 was painted even when i group them it doesnt paint the whole thing

right pink object only gets painted/most recently clicked

Only the active object gets a material assigned. To transfer this material to the other objects while all are still selected, press Ctrl+L > Link/Transfer Data > Link Materials.

Does this answer your question? Adding materials to more than one object


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GN: How to distribute points percentage wise or by arc length on a curve between a start and an endpoint?
In common CAD programs there is a function with which you can distribute any number of points on a curve as a percentage / arc length between the start point (0%) and the end point of a curve (100%).
How can you easily realize something like this with Geometry Nodes?
The picture below shows two examples, one from the center curve and one from the left boundary curve. In this example, four points are distributed along each curve, starting at the top. The first point is placed at 20% and the last at 80% arc length. In between, the remaining points are distributed evenly.

Another consideration would be to scale the points along and on the curve. How can you set a point to scale from? For example the point in the middle of the curve?
All in all the idea is to be more flexible in the distribution of points on a curve.
Many thanks in advance for any assistance, support or helpful ideas!

The "percentage" in your screenshots is named (Curve) Factor in Geometry Nodes. It is available as a manipulation mode in a couple of curve-related nodes (Trim Curve and Sample Curve, off the top of my head) and also as an input field socket on the Spline Parameter node. It's just based on float values between $0-1$ instead of a percentage.
Here's a setup where I use Trim Curve to determine the start and end "percentages" of a Bezier Segment. Then I subdivide that leftover curve to evenly distribute some spheres. Finally, I control the scales of these spheres according to their placement factor with the help of a Float Curve:

Thank you @Kuboå!! This is exactly what I was looking for :)

If you divide the index $+1$ by the number of points of the curve you'll get a number from $0$ to $1$.
Then you can use a Compare node and a Boolean Math node to choose where to instance.

Thank you @Luiz Antonio and @quellenform! This is also very useful, which I will certainly apply later :)


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Raycast: How to limit projected curves only to Target Geometry and omit gaps?
After the raycast, I want only the curves to remain on the target geometry and not, as can be seen in the image below, that the curves in the gap area are still present and connected. Which setting do you have to choose for the raycast so that the curves are only projected onto the target geometry?

I have already tried to delete the curve segments that are not on the target geometry with Delete Geometry using a Boolean operation (Boolean Math > Not) and the Is Hit Selection. Which didn't work. In another attempt, I tried to convert the curves into a mesh via Curve to Mesh Node, then to build an intersect with Mesh Boolean. That was very computationally intensive and caused blender to crash... Is there an effective workaround for this issue?

Many thanks in advance for any assistance, support or helpful ideas!

Hello ! Not sure if you want them to not move or .. ? You can try a Delete geometry node, invert the Is Hit output from the raycast not with a boolean math set to Not and plug it into the selection input of the delete geometry node

Thank you for your quick reply @Gorgious! I want the white curves only to be projected onto the target geometry. Everything that is not on the mesh should be deleted completely... So in the area of the hole.
I have actually already tried the Delete Geometry Node combined with the Boolean NOT. Unfortunately, Bledner does not delete the curve sections in the area of the hole. It doesn't matter if I set point, edges or spline in the dropdown menu...
Maybe I have a misconception

This is based on Gorgious suggestion.
The origin of the object seems to be locked at World Origin, so if you connect the position to the ray direction, it gets weird (although I'm not entirely sure about this - maybe someone can explain?).
Anyway. I Resampled the curve to get more definition, converted it to a mesh, and used the Delete Geometry node (set as Edge for better results).

Thank you @Vagabonk!! That's exactly what I was looking for :)


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Using the Screw modifier, how do I accurately set the axis of rotation?
I got two good answers to my previous question about using a profile to create a mesh.  The problem I am still having is that I can't get the axis of rotation in the right place.  One thread said to position the 3D Cursor on the axis and another said to move the axis to the Origin.  I redid this three times. The last time was the closest. Still, the axis of rotation varied from ideal. How do I position the 3D cursor more accurately so as to make the axis of rotation where I want it to be?

Select a vertex and press Shift+S > Selection, see if that helps

See http://blender.stackexchange.com/questions/1291/change-pivot-or-local-origin-of-an-object/

The screw modifier simply uses the object's origin as the point of rotation, this answer shows how to reposition an object's origin.

Just wondering : are you talking about the screw modifier (that uses object axis and rotates around the object's origin) or the spin tool (wich is rotating around the 3D cursor using view axis)?

The modifier uses the objects (local) axis (X, Y, Z)
Modeling from top side or front ortho view will make things simple. use numpad5 to switch orthogonal/perspective view
Shape modeled in top ortho view (green line is Y global axis)

Screw modifier set on Z object axis

Screw modifier set on Y object axis

Once modeled, you can move your object or rotate it (object mode) but in edit mode, you'll get a mess. Apply modifier or clear rotations for editing.

@ideasman42 Good point, thx for edit.

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


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Set origin to vertex in Edit Mode?
I want to make the origin in Edit Mode at a vertex, but it keeps setting it to the last clicked-on face.
Now in Edit Mode the pivot is on the last clicked-on face.

I'm not entirely sure what you mean. I suspect you want the Pivot (the location of the transform widget, RGB arrows) to remain on the last selected vertex while both vertex select mode and face select mode are enabled. Is this correct? If so, could you explain why you want this? AFAIK it's not possible but perhaps we could come up with a suitable alternative if we knew the use-case. If this is not what you want, could you clarify?

More information is needed.

If you enable the shipped add-on: '3D Viewport Pie Menus', CtrlAltX will bring up the Origins pie, which includes 'Origin to Selected' in Edit Mode.
(On my system, I've had to remap it to ShiftAltX, because of conflict with the OS.)

A practical alternative is:

Enter in edit mode (in this mode the origin menu in the tool
shelf hides and you are no more able to use it, but don't worry...);
Select the vertex (one or more vertexes or edges, or faces) you want to use as referring for the new origin position.
If you select more of them modify the Pivot Point to Median Point
so blender will automatically calculate the median point accordingly
with your selection;
Press space bar to show the dynamic space bar menu;
In Search text box of space bar menu insert: Set Origin to
Selected; Confirm with Return or left click on Set Origin to
Selected menu item;

Notice: once done the first time, you will be able to access and apply the command in future just pressing space bar and Return, until you don't search for another command into space bar dynamic menu.
The screenshot:

Fast and effective...
Enjoy...
PS.: I don't know if there is an item in the tool shelf for Set Origin to Selected though: if there is I can't figure out where it is... In fact I use the space bar dynamic menu
Hope in the future blender releases the origin menu doesn't hide in edit mode and hope developers will add some more good options like the above so can be found faster and visually.

I don't have that option ;-;    nevermind I found a script that does it https://ghigiblend.wordpress.com/2011/11/25/script-set-origin-to-selected-blender-2-6x/

@UanpisCardada, Notice that I'm not sure yet if the command I used is blender native or comes with any plugin. I just activate all plugins in blender just out of the box

This option comes fromt he plugin "3D View: Dynamic Context Menu"

If you are trying to change the pivot point for a group of vertices I would try selecting a point and use Shift+S and Cursor to selected. Then at the top center of the window there is a small button with a drop down menu that says, "transform pivot point". If you select the option for 3D Cursor then you can use it as a pivot point for a group of selected vertices within an object and still stay in edit mode.
Sorry, I don't know the fancy terms for everything yet. I'm just getting started with Blender and figured this out myself.

Select the vertex in Edit mode.

Press N. Transform->Vertex.

Under the vertex coordinates change display values from Local to
Global.

Copy and paste vertex coordinates to Transform->3D cursor-> Location.

Put pivot to the 3D cursor coordinates.

Thank you, Timaroberts.

If you come from missing these options in the fashion of the Object Context Menu > Set Origin > ... and want to have this available real simple and quick, enable the Interface: Dynamic Context Menu addon and then you can find Origin to selected V/F/E available in the search menu. Just select your vertex/edge/face in edit mode beforehand and voila, the object got its new origin.

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


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Finding out which polygon a vertex belongs to in AN
How can I find which polygon a vertex belongs to in AN?

you can do something like this:

Thank you so much... That helped a great deal!


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How can I make an oblique rectangle shape for wooden line braces?
How can I make the shape, pointed at with the yellow arrow?
This is actually an image from a tutorial. I am trying to make this whole framework, for now, I am just trying to make a shape that looks like the one I am pointing at with the arrow. So basically this rectangle shape where the faces are sort of rotated away from each other.
As you can see this sort of oblique shape is quite common in the whole wood framework.

It's difficult to see exactly what you're trying to do without more images. You seem to have odd vertices selected all over your model in your image. If you could explain precisely what you're trying to achieve and maybe share your Blend file via https://blend-exchange.com/ following the instructions there we might be able to help.

This is actually an image from a tutorial. So in the end I am trying to make this whole framework. For now, I am just trying to make a shape that looks like the one I am pointing at with the arrow. So basically this rectangle shape where the faces are sort of rotated away from each other.

I am going to copy that comment to the question, because it is essential information for people to be able to understand what you are asking. I hope you don't mind.

Thank you for that! I should have made it more clear

Hi Please use a title that reflects the content of the question. It should be descriptive but succinct, unique and identifying, summarizing the issue so that users can at a glance understand what your post is about. Use the [edit] link below your post and avoid anything not strictly essential to the post. Remember, your title is the first thing potential visitors will see, and makes your question findable for future users. See "What is the problem with posting an image or link and asking “How do I do this?""

This answer might be relevant. There might be a less fiddly way.. still waiting for it :)

If you have more complex geometry like bevelled edges or something like that, you can also use the Shear operator. You can search for it with search menu(F3), it's in Mesh -> Transform menu and the hotkey is Shift+Ctrl+Alt+S

It's a bit weird, because it works with screen space coordinates X(width) and Y(height), so you need to look at the model from the side(like I enter "Front Orthographic" view with Numpad 1 in the example) and press Y or X to constrain operation axis. Numerical input works during operation with it so you can hit 1 for full 45 degree corner and -, or -1 from the start if you want it in the other direction, or you could also enter any other float value:

Like I mentioned in the comments, shear is transform operation so transform pivot point settings define the point it originates from. In the example below you can see me set the transform pivot point to 3d cursor and snap the 3d cursor to a vertex point. It doesn't need to be 3d cursor, it could be any of the options - for example you could use active element as the transform pivot point and simply select your chosen vertex or edge last to make it active and achieve exactly same result.

I often use shear to make various frames, windows, profiles, ceiling mouldings and what not and I find myself in situations where I need to zoom out and zoom in to see where the next corner is so it's often convenient to not worry about it at first but later snap the geometry to something else in the scene so that's another option - you can just move or snap it in place where you need it after the operation.

That works great! But how can I make sure it keeps the edges the same size? When I shear like this, my 'square' face becomes rectangular. I want to keep all the sides the same size.

Shear is transform operation and transform pivot point settings work with it so you can define the transform pivot point as with any other transform operation like scale and rotate. I'll update the answer with explanation in a few minutes.

In Edit Mode scale a cube on one axis, then select one of the non-square faces, and further scale it on the same axis:


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Object not showing on render view
My object is not showing in render view and a all the videos on Youtube that I could find are not helping. what is the problem?
I am a beginner in Blender.

Hello, there is no light in your scene, maybe it's your problem here?


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Why can't an emitter go past 200 frames
I want to make a cover for a preview of my first animation, so in he middle of my animation video, I put all the models in the main set to make a cover for the video, and grabbed one of the cameras.
However when I render it, it just shows the render of the last frame I did on the animation. Its like Blender doesn't want to shoot the cover and just wants to get back to the animation.

How is the title related to the question? Your objects are animated so probably keyframed, so when you render them they revert to the animated position at that time, rather than the random place you temporarily overridden them to.

I forgot to change the title. Sorry

It is not too late to fix it

If I understand your question correctly:
By default, in your particle system the particles emit from frame 1 to frame 200.
Try to increase the "End" value.


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How do you model a curved boolean like this?
How do you model a curved boolean like this?

Isn't there just a cylinder going through the U-beam? How did you get this result?

it was a step file which im going to remodell myself. the description here was the same way i tried my self. i think i failed with the mesh cleaning. ill give it a new try. thx. great community here!

Eh, I don't know how to title this... "How do you model a simple bottle opener"? :D

actually it is a piece of a crane arm...

You could create 2 perpendicular faces, bevel the angle:

Cut a half-circle with the Knife Project tool:

Result:

Clean the topology:

Cut the half-circle, give your object a Mirror and a Solidify modifier:


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How to rename the layers in 2D animation
I want to have an organized layer by changing the names, but I don't know how.

You can double click on Layers name, either in layers panel, GP dopesheet window or even outliner.

Or press F2 with the name hilighted.


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Can I mirror around a cylinder
I am trying to create a propeller but I want all sides of the propeller to mirror around a cylinder. If I edit one face of the outside of the cylinder, I want it to copy that to all the other sides of it. How could this be done?

Probably an array modifier rotated around the center point

or a Simple Deform modifier (Bend mode), but maybe show a reference picture if you have one

what about this?

first model the propeller, then separate the object from the cylinder and give it a mirror modifier.

I need 16 blades

Hi Jett t, i know you are new here, and if of course you can comment to an answer, which might have needed 30 mins to make it "i need 16 blades" instead of "thank you very much for your effort, but unfortunately i forgot to mention in my question, that i need 16 blades, i will edit and update my question". And so my comment to your comment is: please edit and update your question that it is crystal clear what you want and keep this in mind for future questions. "Updating" a question by just comments is pretty bad behaviour and not useful. Thanks.


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How to create a 3D wireframe lattice to use for internal support of a 3D FDM print
After much searching I saw articles written about using two modifiers: Wireframe and SubDiv.
I thought this was the greatest thing from the pictures. However I've spent some time creating rows of cubes. Eventually getting to the process of scaling a unit cube x times, inserting x-1 loop cuts, going inside this mesh and placing faces internally to create x cubes. Upon applying the modifiers the internal corners, let's say of a 2 x 4 matrix of these cubes, are not rounded like the exterior corners.
I'm developing a product and if printed as a solid... would waste a lot of material. But the object is exposed to 5000 - 9000 psi. This prevents normal infill as an option as the part would implode.
My intention was to create either cubic, triangular, or rhombic dodecahedric structures internally and provide small holes to allow the part to equalize. Wireframe + SubDiv is almost there...I just require a vertex joining 8 cubes to have 6 cool looking circular edges... ideally with a larger diameter "ball" at the vertex, then get the 6 edges with 4 distinct lobes.
The latter is weak... and I can't use support material so the use of curved surfaces getting to the right angles generally works well.
Imagine Wireframe + SubDiv on a single cube with a small/no crease weight and the SubD iterations at 4... the internal structure of that cube would be the exterior surface of this lattice I would like to create. To better visualize can add an array modifier to it. Better approximates the goal.
How can I accomplish this?

Blender has no functionality for this. You should create infill in slicer software, because you will not be able to control gcode in Blender and whatever you model will get sliced so it will not be as strong as what is made from continuous lines slicers use for infill. If you need stronger prints, print thicker walls and denser infill. You can have a range from 0% to 100% density of various infill patterns including triangular infill. If that doesn't work, it means it's not the right material for the purpose. It's best to use tools intended for the job in this case.

If the object is exposed to 5000-9000 psi, he might need to do FEM on the model.  I'm not sure if there are slicers that will send give you the solid after slicing...  But your point about using the right material for the purpose might be correct here.  Why try to be genius in engineering when you could just be genius in design and planning?

It all depends on the specific situation. If a solid part works, maybe a part with thick walls and 80% infill will work as well. Maybe using gyroid infill and some holes in the print for the pressure to be equal inside and outside might work. I own FDM printer and my modelling skills are quite OK since it's part of my job for many years but I can think of no situation where I would want to attempt modelling infill manually. Whatever structure you can model and then slice, infill will be stronger and easier unless you need the structure for something else than holding shape.

I took biotechnology and computer science Wish I had done engineering at the moment, Lol. All my thoughts really may not matter... thick walls and 80% infill may be fine. But I don't know how to use the TDS numbers to determine this. Initially I was going for thick walls and the purpose of these was to maintain the shape by providing curves up to the ceiling of the cavity instead of a 1+ inch gap that needs crossing.... but this might come down to slicer settings... fan only on gaps possible? I can just go solid but thought why not try and make more parts with the same amount of filament.

@NolanRobidoux if you haven't already, post in the engineering or 3D printing stack, and provide very top level overview of what needs to happen.  For instance, I am unsure if by "internal support structure" you intend for a structural infill, or for something to aid the print geometry (prevent overhang).  By "equalize", do you intend to say this will be exposed to a 9000 psi fluid?  Can you print the part and drill a hole after the print to create the geometry?  So many unanswered questions here on my end.

@WhisperingShiba I redesigned the part. Essentially collapsing it in a sense... bringing the hollow space inside, outside. But to answer your questions, I  was just going to place holes in the model to allow water to flow through. That way the entire part is exposed to 9k psi not just the exterior.  Your last question... I think I'm reading it correctly. If I am... FDM can't do that. Although someone somewhere mentioned injecting the part with open cell foam... not sure how quickly water penetrates. We don't really sit around waiting.


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Getting Uneven UV for Curve in Geometry Nodes with Capturing Attributes
I've seen this questions posted in places before, but haven't found an easy workaround yet. There's this answer but it's kind of complex...
The standard way to do this as mentioned in this thread is to use capture attribute. I have a simple Curve to Mesh setup that uses this method:

Is there a simple way to just make this UV 'even'? Because the logic should be there, but not sure why one part of the seem is just super compact and disconnected...
Hope someone can give an answer to this, or maybe improve this in a new update :3

I am currently working on a simpler solution regarding the question you linked. Have a little patience, I will publish it soon.

It looks like your curve is a vertical line that you bevel with a circle, making a vertical wire, and you want to make the UV of the caps even?


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Randomize values for each nested Geonode?
I have a nested geonode of generated plants, and I want to randomize these plants with another geonode.
But once I plug into a random value into the instanced plant, it shows me an error.
Is there a way to work around this? Or am I not doing something right...
Here's my file

Hello! This question has been asked many times in different variations. A good explanation, why this unfortunately does not work and what other options are available to you, can be found here: How can I instantiate a procedural node group with different parameters?. The following post may also help you: Why is there a red line when I try to connect one node to another?.


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Why does StoreNamedAttribute's Vector Type for UVMap not work in place of 2DVector type?
I'm trying to make this setup compatible for version 3.4 but I don't understand why simply switching 2DVector to Vector didn't work when, based on my understanding, Vector would just need to ignore the z component to make it compatible with 2DVector and the UVMap which uses only xy plane. Did I misunderstand? The texture suddenly becomes plain colored when switching to Vector.

Can you show how you use the attribute UVMap in the Shading Editor ? Do you set Z coordinate to 0 ?

Hi @StefLAncien thanks for your response. Does this one help? I have a blend file here in this thread. Just change one of the materials to a texture to see the result.

(Using Blender 3.6.8)
It seems that in the Shading Editor, the UV Map node is expecting a 2DVector type, and that if the attribute UVMap is a Vector (i.e. 3D), it is not identified as a valid UVMap. But using an Attribute node to recover the named attribute UVMap instead of a UV Map node seems insensitive to the type, 2DVector or Vector.
With 2DVector:

With Vector:

Sorry, I do not have access to Blender 3.4. I am confused because documentation of version 3.4 is referring to 2D Vector type already (see https://docs.blender.org/manual/en/3.4/modeling/geometry_nodes/attribute/store_named_attribute.html and https://docs.blender.org/manual/en/3.4/modeling/geometry_nodes/attributes_reference.html#attribute-data-types)

thank you for this post. yes i was looking for a pure geometry nodes solution so i could make it work out of the box without needing to adjust the shaders as well..

actually both Attribute ndoe and UVMap nodes in the shader tree work in blender 3.4, and I think it is really necessary to specify that to make this work. thank you.


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GN: How can I check if the length of the materials list is longer than my current list and then add one to material index?
I come from this thread with a dilemma that I don't know how to properly solve and have presented a minimal reproducible example. Apparently it is expected behavior that Volume to Mesh node will add a hidden Empty Material that is white by default. So if you have 3 materials on your object, you will end up with 4 materials in the following GN setup without you ever knowing. So I'm currently adding 1 to the Material Index to remedy this problem, because that hidden material is disrupting my node setup. But that is very hacky.
So I was thinking maybe I can create a node setup that checks that if the material list is longer than the one I have initially defined, then that means there was something new added to the list. But the problem is it is possible for that new hidden material to be inserted on index zero and also possible to be added to the end of the list. See TICKET-119269. So how will I know when it is added to the top so that I can decide to add 1 to the material list? If it is added at the end of the list then I have no problem. So first I need to check if the list is longer by 1 then check if it is added to the top or bottom list.

Here demonstrating that adding 1 to material index "fixes" the problem.

The hidden material becomes visible once you apply the modifier and it can either appear at the top or bottom of the list:

I think there is a misconception about how Blender handles materials on objects in general and how GN handles materials specifically. It is not the Volume to Mesh modifier which adds a "hidden white material". All mesh primitives show a default when you don't put a real material on them. In GN, newly created geometry has no material like a new primitive. In GN you can set materials for geometry, even if they don't exist on the GN object itself. The problem is, once you apply the GN modifier, the created objects needs to have the materials, otherwise the materials could not be assigned.

And here comes the issue with the "hidden white material". An object needs no material to show the default white (light grey actually) and therefore no material slot. But as soon as you put just one material (and with it a slot) on it, by default all faces get this. To have some faces show other materials, you need to add them and assign them to faces - which the GN nodetree did. But if there are faces where GN did not assign, they cannot be left unassigned on the "real" mesh pnce other materials. Therefore it creates an empty slot (without material, not hidden) to assign to those faces.

To learn more on material slots and material assignment, you might read my answer here: something strange with material slots because that's how Blender basically works with materials on mesh objects... and this is what it comes down to when you apply the GN modifier.

Thank you Gordon for sharing!

I'll write this as an answer to be able to illustrate this additionally to my comments and to show what is going on there.
The problem with your answer is, it works in this specific case, but it does not generally solve the problem. This answer is just to make you and maybe others coming across this question aware of what happens.
Every mesh object comes with a default "appearance", this dull light grey material, to have some kind of shading to be shown in the viewport. A mesh object shows it by default, it is no actual material, just an internal default how to shade surfaces without material and it does not need a material slot for it.
As soon as you add either an empty material slot or a material which automatically creates a slot, all faces of a mesh object will be assigned to this slot. Adding more slots do not get assigned to faces automatically, they have to be assigned manually.
In Geometry Nodes, original meshes keep their material like the base mesh if it has one, or objects brought in with Object Info node for example. All these can have new materials assigned with the Set Material.
New geometry generated inside the GN nodetree does not have a material and does not use the material from the base mesh. Therefore you have to assign materials with a Set Material node to them if you want them to appear different then the dull light grey default surface.
Now here comes the crucial point where your solution might get a problem in other cases than the specific one here: with the Set Material node you can assign any material that is in the scene to geometry in the nodetree. The base object holding the GN modifier does not need any material at all, the materials only have to be somewhere in the scene like on other objects for example, which do not have to be represented in GN with an Object Info or anything.
Like in the following image. The base object, a cube, has no materials and not even an empty material slot as you can see on the right side in the Material Properties. However, the three different objects I created in the nodetree all have their own material assigned to them, one red, one green and one blue.
These materials are on a different object in the scene and can be "stolen" by the Set Material node. The reason why you can have materials on the GN objects without any material slot is, they are "virtual" geometry, procedural, not yet "real" meshes.

When you now apply the GN modifier, the procedural geometry gets converted into a real mesh. A real mesh cannot have materials assigned to faces without having those materials stored in material slots. So either applying could remove all materials since the base object has no material slot, or - and this makes more sense since applying the modifier is supposed to result getting what you virtually have now as real geometry without changing the appearance -  there have to be material slots created holding those materials. This should not come as a surprise, even without using GN, when you join two objects with Ctrl+J and they have two different materials in only one slot each, the joined object now has two slots, one for each material.

And because the base object information is kept in the GN modifier
to be available with a Group Input node even though it is not contributing to the output geometry, you will get an empty material slot here as well, because the now no longer visible faces of the original base mesh did not have a material assigned.
Whenever an object has at least one material and therefore a material slot, no face can be "unassigned" to a material slot. Each face is assigned to the default slot or manually to a different slot if existing.
Applying the GN modifier now preserves this unassigned part of the original base mesh by adding an empty material slot without any material. But since the original mesh is not contributing to the output, it is not plugged into a Join Geometry node and you cannot change its order for the output. In this case, the empty slot will always be on top of the materials at index 0.

Ah interesting thank you for sharing! So there is currently no solution? I see it was solved only in my case, but I realize that the order of joins like in this case doesn't matter and would still put the slot at the top which could potentially mess up the resulting output when dealing with other setups that tinker with material indices?

Well, the problems I describe here are mostly just occuring as long as you are not aware they could occur. A solution could be, the base object needs to have a material, each geometry created in the nodetree contributing to the output needs to have a material assigned with the Set Material node, and all materials used by the Set Material have to be stored in material slots on the GN modifier's base object. And when all materials are already present in existing material slots, the order in the Join Geometry does not even matter since no new slots would be added.

Nevermind I realized a very simple solution was to swap the socketing of the noodles so the empty material gets added to the end of the list and thus not disrupting the node setup!


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GN: How to replace Interpolate domain node with Transfer Attribute domain for 3.2?
I did some research about which nodes to use in which version from this amazing link from quellenform shoutout to them thank you so much it was very helpful.And I'm going from a 3.3 version geonodes to 3.2 where there is no Interpolate Domain node. Based on the link it seems I have to use the Transfer Attribute node instead.

I tried replacing it and trying all the options, but I can't figure out how to make it work.

Blend 3.3 file

Hello, Megan, thanks for  a well-illustrated post. I think you might set folks up to answer a little better, though, if you could edit to  open with a sentence describing what you want to interpolate in this particular case? (A specific example often makes the generality easier to grasp)

sorry i didn't specify i found the solution to use Capture Attribute node. Not sure why this was not mentioned in quellenforms documentation? honestly i'm not so good with geonodes.

Turns out to be no problem :) Glad you found it!  You can accept your own answer, after a while.

I found the answer in the documentation to use Capture Attribute node

It now works.


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Why is one side of the armature affecting every bone?
I am using the skin modifier for the first time and have seem to run into an issue... When making the armature, the right side bones when rotated affected every bone. The left side however is perfectly fine and works how it should... Does anyone know what the problem is?

If you can share the blend file to see the problem, maybe I can help you.

To solve the problem select the bones that were affecting the entire mesh in Edit Mode, go under Armature, and click Switch Direction. Now everything works.


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Undo History as panel
I like Edit -> Undo History in Blender 3.
But what I find annoying is that it is hidden in a menu. Sometimes it would be practical to see directly at a glance where you are in the history.
Is there a possibility for this? Possibly as an addon?

This is a Q&A site for problems with using Blender. If you have a suggestion for a new feature you should post it at https://blender.community/c/rightclickselect/.

It is also a question of whether this possibility exists.
But from your statement I assume that it is not yet possible. @JohnEason

There is nothing native that does that, but it may be possible through python scripting, if you roll your sleeves up

@DuarteFarrajotaRamos thanks. I will look into it.
Do you happen to know how I can access it?
https://docs.blender.org/api/current/bpy.ops.ed.html?highlight=history#bpy.ops.ed.undo_history
Doesn't include a method that allows you to read the history.

You can go into the Preferences > Keymap > Screen > Screen (Global), then at the bottom click on the Add New button and in the new function type ed.undo_history and choose the shortcut:

Now when you press your shortcut it opens a pop-up:

Or as suggested by John Eason, right click on the Edit > Undo History fuction in order to add it to the Quick Favorites panel

Oooo. That's one I didn't know about. Useful! You could also add it to the Quick Favorites by the look of it. (Right-click the menu entry and choose "Add to Quick Favorites").

oh yes you're right, quick favorite as well

Well, that is of course also sufficient. I'll put it directly on a button on my tablet. It's also handy to know that there are several such options in Blender that you can place on a button.


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Earth model loses color on import
I am trying to import an Earth Model that I downloaded. When I load it into my project it loses all of its color and is only grey. When I load the model as its own project it works just fine.
Does anyone have any idea why I lose color on the model when moving it from one project to another?

If the "Alpha" input is in the "Base color" of the principled node:

Then it will look like this:

If you put the "Color" input in the "Base Color" output on the principled node:

Then it will have color:

-
-
Hope this helps!


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HDRI not appearing as the background
I am trying to get an HDRI image load on a small project I am working on. When I go into Shading to set it up, and switch over to Rendered view nothing shows up.
I would really appreciate a solution for this

Disable "film > transparent" in the output settings.


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Trouble Getting Downloaded Model With Textures To Appear
I have been having trouble getting the textures to become visible in Render Mode. I am still very new to Blender and have been learning most things through Youtube tutorials. I have followed multiple tutorials but nothing seems to work to make these textures appear.

Maybe this can provide more insight

how is the render? send print

https://imgur.com/a/Xa4ae6w This is what shows for the Render

already checked the shaders and images?

Sorry I'm still really new to this. Where could I find this?

https://prnt.sc/yoen64

https://imgur.com/a/g89g7On

Let us continue this discussion in chat.


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Unwanted repeating textures
I'm working on an Earth model and when I apply its textures I get them repeating instead of being applied only once. Im still new to Blender, I would appreciate some help

It seems that your sphere isn't UV-unwrapped.
You need to enter edit mode, select all vertices, press "U" on your keyboard and then choose a projection mode that fits your texture. I'd guess that "equirectangular" might be the correct option.


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Is there a way to see more physics setting for an object?
I was following a tutorial oh how to make a basic water simulation then I got to the part where I enable the domain's mesh and couldn't find the "mesh" checkbox anywhere. I seem to be missing a few other settings in the physics tab. Is there some advanced settings or something?

In your second screenshot the mesh checkbox is there, in blue, already activated. What's the problem?

so sorry, the second screenshot is what it should look like ( I was watching a tutorial)

It's under the Liquid subsection, just click the arrow and all will be revealed

Oh my goodness thank you so much somehow that just passed my mind

Click the little button near the Liquid


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2.9 Dynamic Paint Image Sequences Not Working (Nothing was painted on)
I've been trying to recreate a project similar to this:
https://www.youtube.com/watch?v=UMDiSEl2WdE
My probem occured when I tried to generate the 180 frames of image sequences of the dynamic paint for further use as texture.

However, what I got in my directed folder were all black png images...
And I had a difficult time to figure out what had gone wrong..

Here's the detail of what I've done:

Added a 2m x 2m Plane, uv-unwrapped and sub-divided twice + 50 cuts.
Added a curve "ADF Path" based on "ARNODEFRANCE" text and set path animation to 160 frames.
Added a Sphere with object constraint (follow path) and targeted to the curve "ADF Path", offset at 1.000.
Applied Dynamic paint, type of Canvas to the Plane, type of brush to the Sphere.
For the canvas, I selected Image Sequence, Resolution 2000, Frame start 1 end 180, sub-steps
10 (tried also 20), set the initial color to black, UV map to "UV map".

For the brush, I set the paint color to white and nothing changed from the default.

I then baked the image sequences, without premultiply Alpha since I do not want any alpha channel.
Yet, nothing was painted on the canvas...
Could anybody see right through the problem or mistakes I've done?
Thank you!


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How to make Bezier curves follow a reference geometry using Geometry Proximity?
since my last post GN: How to adjust Bezier-curves with geometry proximity to get streamlines? I've managed to get the streamlines into dependency of the two outer reference curves.

Now after numerous attempts I am still facing one or the other problem:

The streamlines now follow the curvature of the two reference curves and blend / distribute into each other from top to bottom. For this I plugged the output of the Geometry Proximity node into the offset input of the Set Position node. Unfortunately, the start and end points of the streamlines also shift.
How can I adopt the respective curvature, but keep the start and end point of the streamlines in the old position or transfer them back?

As the reference curves get more complex, the streamlines no longer follow them exactly, even if I increase the resolution of the streamlines using the resample curve node.

How can I control the influence of the Geometry Proximity node? The Map Range Node didn't work for me or I wasn't able to use it properly. The goal is still to achieve this:

I hope someone can help me to find a solution. I'm also very grateful for every tip!

Have a nice remaining weekend everyone!

Let's use only two curves. A source curve and a target curve. We are going to add geo nodes to the source curve, to instance it and the interpolate the duplicated splines to the proximity position.

Resample the curve and get the closest position of the target curve (with the Proximity Node). Store the target position with the Attribute Capture Node.
Instance the curve a few times in place. Capture the instance id and then realize the instances.
By calculating captured_id / instance_count we will have a relative value [0, 1) to mix the original point position with the target position.
Use the captured target position to mix the positions.

This setup is limited by the geometry proximity, but that was the premise of your questions title.

That's exactly what I was looking for!! Thank you @Leander

@pb1893 If your question could be answered satisfactorily, please consider marking it as "Accepted Answer" so that this question appears as solved. Thank you!


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What's the difference between the Wave Texture Nodes outputs?
Here's the Wave Texture Node:

It's got two outputs: "Color" and "Fac"
The documentation defines them as "Texture color output," and Factor is defined as "Texture intensity output."
Experimentally, these always seem to be produce the same thing, as far as I can tell. What's the difference betw?

It's the same as on other texture nodes, a Color output gives a 3-dimensional vector as output value, while the Fac gives a 1-dimensional floating point value as output. Which means Color gives you RGB values (which can be taken or interpreted as XYZ values where needed), whereas Fac gives a greyscale value between 0 and 1.
In case of the Wave Texture node this does not seem obvious, because when you choose an axis e.g. X, it takes the X values and outputs them on R, G and B channel which only results in greyscale values as well. I guess it is mostly to keep the texture nodes consistent to have both, a Color and a Fac output.
One thing might be that if some nodes only accept single values as input you would have to take the Color and a Separate RGB/XYZ node to pick one of those values. Or if a node only accepts vectors and you have a Fac output, you would need a Combine RGB/XYZ node and plug the greyscale value into all sockets to create a vector.
Now in almost all cases Blender is doing this automatically. Plug a greyscale value into a vector socket: automatically the value will be set on all three channels RGB or XYZ. Plug a color into a single float socket: Blender calculates a grey value from these three channels and sets it as value for the input.
However in some cases like the Noise Texture it is not the same. A default color ramp with black and white on left and right end converts colors into grey values, but the output of the Fac value and Color converted to greyscale do not give the same result.
This has something to do with chromatics, how color intensity and saturation are perceived and how they are displayed with Gamma correction and other things which are now too much explain and I'm not really an expert for this. Just keep in mind, a Color output gives a vector result and a Fac output gives a float value. A Gradient Texture is the same, you only get greyscale colors from both outputs, but still a Color output is a vector.

I think the implicit conversion from color->float is based on L in a HCL color model, whereas I believe the noise Fac is the V of a HSV color model.  The former weighs green more heavily and blue less heavily (perceptually, we describe 010 as brighter than 001.)  Implicit conversion of vector->float is the average of the three components (which I think is the same as V in HSV.)  Blender's variable typecasting is really weird and confusing and black magicky.

@Nathan No, it's not black magicky and there's enough resources for colorspaces and methods for color conversion, sRGB displays etc. on the web - but I don't think it's necessary to study those things just for answering the question why there are Color and Fac outputs on the node although they both output greyscale colors.

Sorry, I didn't realize you were just skipping over details for anticipated question interest.  Makes sense!


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Embossing a model's texture onto its mesh
I've got an .obj file that I've imported into Blender from another application. The imported model includes a complex texture nicely mapped onto it, and it renders nicely. However, I'm planning to 3D print the object, and so I'd like to get some of the detail from the texture onto the model.
I looked around and found the "displace" modifier, which seems like it should maybe be what I need, but I can't figure out a way to tell it to use the texture that the mesh is already using. Instead, it seems like the modifier wants me to create a new texture?

In the modifier click on New, choose Coordinates > UV (1) and click on the button on the right (2):

It will automatically open the Texture panel, here click on Open and select your bump map:

Back to the modifier, tweak the Strength, also make sure that the object is subdivided engouh to get enough details.


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Why are my camera tracking markings not in view of the camera?
When I solve camera motion and set up tracking scene my camera does not point at the tracking markers. It also shifts the picture in the camera view down for some reason. The picture is not clipped in the tracking editor. I was not having this problem until a seemingly random resolve caused it.

Resolving the camera rotates the camera a little bit but the image is still clipped and the markers are still not centered.

I figured it out. I was refining for optical center and it moved my optical center off screen. Resetting the optical center fixed the problem.