text:
How can I adjust the position of shadow according to the light source in 3d viewport?

Although I adjusted the position of light in 3d viewport, the position of shadow did not change accordingly.
I want the position of shadow catch up with the change of light position in 3d viewport. (not in rendered mode)
Would you please help me?

Hi. I think you should have shadow here. Could you upload the blend file? Please use this link to to it https://blend-exchange.giantcowfilms.com/

@lemon Well... I guess that you think problem a little difficult. Not in rendered mode(ex: solid mode or look dev mode) I want the shadow of object(ex:cube) change it's position according to change of the position of light source like in rendered mode.

I don't think solid view is intended to manage light shadows. Though, you have a "world space lightning" option that can give a one direction light source.

@lemon Ok thank you good man.


text:
Is there any way to change ui to v2.80?

I downloaded a blender file and opened it but UI did not match V2.80.
I guess that because the file have been made in old version its UI did not match V2.80.
I want change UI as V2.80 easily.
Is there any way for me?

See also https://blender.stackexchange.com/questions/2151/is-it-possible-to-use-the-startup-blend-ui-layout-in-older-files

@rjg Thanks for your good answers. But I wonder if there is any way to change UI after opening an old version file.

@Mr zak Thanks for your good answers. But I wonder if there is any way to change UI after opening an old version file.

Not that I'm aware of.

@rjg Ok have a good day.

Yes changing UI without reopening file is probably impossible due to major differences between versions which leads to quite noticeable incompatibility

source: Stack Exchange

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

sort: votes


text:
Why 'bridge edge loops' do not cut holes in my work?
I know that faces enclosed by loops disappear after 'bridge edge loops'.

But in my work, square caps still exist after bridge edge loops.
Why they didn't disappear?
In this example square caps did disappear.

I think this is because there is only one face at each end. With more faces a decision can be made to what faces are inside the loop and which are outside.

@smabler Well, I guess this is a difficult problem.

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


text:
How can render overlapped object's edge freestyle line?
When I overlap 2 objects like this

resulting freestyle lines are like this

But I want render overlapped edge lines like this(red lines below picture)

What's the easiest way to accomplish my purpose?(A lot of objects in my work are made in that way so resulting render image misses many overlapped edges. I tried to remake some object to reveal overlapped edges but I realized that remaking all objects is too hard to me.)

It seems not possible: https://blender.stackexchange.com/questions/52526/freestyle-with-multiple-objects

thank you. but i'm really sad.

I've tried to do it with 2.8 using the Workbench engine. Not perfect but maybe have a look to it.

You may want to checkout LANPR which is currently in development as a possible freestyle replacement.

Do you want face intersections, or hidden edges?

@Robin I want face intersections.

This is essentially the same method as @Rich Sedman's; he is passing a convolution kernel over an image to detect edges, 'by hand'. Whereas this is necessary in shader nodes, (if you are trying to kick the renderer into doing it,) in the compositor, various edge-detection filters are provided:

Here, a Sobel filter is passed over the Normal output, to detect edges in it. You may tweak the other nodes to your desired outcome: here, the Dilate fills some gaps, the Color Ramp converts to B/W, with a soft threshold, and the Blur antialiases the result, somewhat.
As in Rich's answer, the same edge-detection could be applied to other discriminators, such as depth, depending on your scene.

Very nice - that is far simpler.

Wow! i don't think I even need to use freestyle anymore! 'cause theoretically, Normal difference is almost the way 'crease' works. which is what I'm mainly using. And a image alpha Erode(outline) could be 'external contour'. 'Cryptomette' + 'Erode' could be 'contour'!

@ZonyZhao all sorts possible in 2D... and don't forget Grease Pencil > Line Art

This isn't possible (as far as I know) using freestyle. However, it is possible to fake the effect in the Compositor by looking for sharp changes to the rendered Normal and/or Depth.
To achieve this, we need to compare each point in the render with a neighboring point and highlight those areas where the Normal or the Depth varies by a significant amount between those points. This can be acieved with a node group as follows :

Here we take the Depth and Normal as inputs and translate each by a specified X and Y (multiplied by the desired Thickness) - this allows the current pixel to be compared with a neighbouring pixel.
For the Normal, the RGB Subtract node compares them and the result is separated into its components and its overall magnitude calculated (as 'sqrt(r^2+g^2+b^2)'). If the result is greater than a Threshold we have found an edge.
Similarly, the Depth is subtracted from its neighbour and the Absolute result compared with a second Threshold. The two results are combined using the Maximum.
In order to avoid artifacts from features in particular directions, we can sample neighbouring pixels in different directions. This can be achieved with multiple node groups with different X and Y offsets - one above, one below, one to the left and one to the right (ie, (0,1), (0,-1), (-1,0), (1,0)) and the results combined as follows :

This can produce the following results (after tweaking the line thickness and thresholds) :

Can we avoid a few nodes here, by letting something like Filter > Sobel do the convolution of the Normal pass etc. for us?

@robinbetts IDK, possibly. Feel free to submit and answer using another method. I’m not really familiar with how that filter operates.

It is now possible to:
Create a blank Grease-Pencil object in scene, and give it a Line Art modifier, which includes the option to detect intersections.

It needs a camera to match to, and will exist as geometry in the scene, which will be continuously modified according to camera-angle. It can be rendered without the modifier's target objects.


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what's the use of edge made by 'f'?

As you know, edge made by 'f' shortcut across a face do not divide the face.
I don't know why this type of edge is necessary in Blender.
Is it not sufficient only one type of edges(dividing face) exist?
Please tell me the case in which 'f' type edge should be used.

One case where I've used F on a face is when I want to create a new object starting from some of my pre-existing geometry. By using F then P, you get an edge that won't affect original mesh when you separate it out. In the case that you just added a new object, you would've had to snap the vertices onto the old object to line things up. While it doesn't save a lot of time, the little things do add up.

Also, trying to create a check for "don't fill in the edge if the two vertices are part of the same face" can become problematic very quickly.
Take this example below: I want to fill in an edge between these two vertices. They're all part of the same big n-gon and I clearly want a new edge, but a blatant, "don't fill in an edge if the vertices are part of the same face" block would prevent me from adding the edge entirely.

There are many cases where it's better for the devs to design Blender in a way that helps prevent users from making mistakes. However, in cases like this one, it's probably better for the user to avoid making mistakes rather than having the devs try to do the thinking for you. It's more likely that the devs will introduce bugs, and it isn't worth the time to implement when there are many other bugs and features that they could/are working on (in my opinion).

If you select a face and hit f, nothing should happen. If you select 2 vets and hit f, an edge is created between them, if you select 2 edges and hit f, a face is made. Blender does not care in what scenarios you use these functions so you can make all kinds of useless geometry with them, or you could make geometry that is useful to you - that is up to you as you are the creator and Blender is a tool.
Connecting verts and edges is one of the most basic functions in modelling in Blender so it would be hard to give examples of the use cases for it as it can be used for pretty much anything. You could do 3d modelling by only duplicating vertices and connecting them to make edges and then connecting them to make faces if you wanted.

I just wonder why there are two types of edges(made by 'f' and 'j') joining 2 vertices on a face. I think that only one type of edges(which divide face ) is sufficient and the other type of edges(made by 'f') is not necessary.(I'm concerned about the types of edges not functions)  If I'm wrong, there must be some examples which  must use the edges made by 'f'(which do not divide face) on a face. I just want know such cases. Only one case will suffice.

F does not create an edge on a face, it creates an edge between two vertices. If they happen to belong to a face then it creates an edge over that face just because it's there. The face does not have anything to do with the operation, it is just there. The operation is to join two vertices with an edge no matter where those vertices are. If you want to divide a face, any other operator like for example bevel operator is also no help at all, do you think it is not needed? No, it's just for another task same as joining two vertices with f.

You are mistaken about my opinion. I do not doubt the necessity of operation 'f' but the weird edge geometry(especially on a face) as a result of 'f'.

This is useful if you want to connect two vertices not connected by an edge already.
If you would like to cut the face into two triangles, select the two opposite verts and press J to join them.

I know use of 'f' shortcut. I wonder what is the use of 'f' type edge on a face. I think it is not necessary in blender.


text:
How can I apply adding object in a collection to other linked collections automatically?

As you can see in the picture above, adding objects in a collection do not applied to other linked collections contrary to editing existing objects.
If there's only one collection linked, it is easy problem solved by linking the added objects to linked collection.
But if there are many liked collections, linking new objects to those linked collections one by one would require a great deal of effort.
So I want adding some new objects to a collection applied to other linked collections automatically just like editing existing objects.
Is there any way that this is possible?

Hello :). It seems that linked collections only work between different scenes. Also,  when they're moved into the same scene, they get merged.

As I understand, creating a linked collection merely creates a new, independent collection with linked objects. But each collection can contain different objects afterwards. If you want the two collections to have exactly the same objects and update in real time, you should look into collection instances. But I think you won't be able to change the active camera, for instance. Otherwise, you could be able to do it with handlers and python scripting to detect when an object is added to a collection..?


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How do I motion track a camera when the scene contains more than one camera?
I'm recreating my house and garden in Blender and as part of the process I'm taking photos from several angels and then motion track them. I've done this on several locations around the property.
As part of a non destructive workflow, I don't wont to delete a camera with it's associated photos when I move on to motion track on the next camera.
How can I choose which camera gets the data from the motiontracker?

This question is a duplicate of: https://blender.stackexchange.com/questions/130240/camera-tracking-reference-scene-to-match-different-shots-in-a-common-space/130351#130351

Rename the "sets" of photos, so that they are seen as a single image sequence with continuos numbering.
Track specific elements that are common in different "sets" of images.
Use "Join tracks" in places where the tracked items are not recognized, or change placement dramatically, become occluded, or re-appear.
Read the following links: Joining 2D tracking markers with an offset and Motion Tracking objects that go out of frame and re-enter later

I don't have any problems with the tracking itself. The way you describes it works like a charm. The problem is when I press solve, the solution is applied both of my cameras. Camera and Camera.001. Are there any way of leaving one of the cameras untouched and only apply the change to one of the cameras? Then, as I import another sequence of images I can track them and apply that camera motion to the other camera.

I don't see why you need more than one camera, but you might have compelling reasons beyond my understanding. There is no automatic way to correlate the information from different cameras, or at least not with the help of some clever scripting (it would be beyond what I can help with anyway), but know that matching things manually is quite simple. track elements that are known entities (the corner of a wall) an outlet, some mark on the floor, etc). Solve the cameras and create "tracks to empties", move the empties so that they match with the others from other "camera solution"

the tracking information is a constraint, so moving one element will make the other empties (and camera) follow along. Read: https://blender.stackexchange.com/a/10708/92768

The most important element for this to work is that you set the scale correctly. measure the distance in the real world between some of the elements used for tracking. then use that scale for the reconstruction Read: https://blender.stackexchange.com/a/143805/92768

I'm building a scene by taking photos from several places around the property. At the end I would like to go back to render the scene from those exact locations so I can use the render to composite with the original photo. --- The problem now, is that as soon as I try to motion-track camera number 2, all the data from camera 1 is also updated with the same data that belongs to camera 2. Now, I can't go back and render the scene from camera 1.

This task might be not for blender. Use meshroom (or any other photogrammetry software). It will take as many cameras as you want, and create a 3d mesh (and materials) out of the many photographs. The cameras can be different kinds of cameras or different lenses too.


text:
Python select empty action line in NLA Editor for Blender 2.8 API
I want my script to add the selected object to the NLA editor, add an empty track, and then add an action strip to that track.
When I call the tracks_add function, I get the error "Select an existing NLA Track or an empty action line first." Here's my code:
import bpy

# find nla editor area for proper context
area = None
for a in bpy.context.screen.areas:
    print(a.type)
    if a.type == 'NLA_EDITOR':
        area = a
override = {'area': area}

# check for animation data
bpy.ops.nla.selected_objects_add(override)

# check for existing animation tracks
bpy.ops.nla.tracks_add(override)

In the UI it's easy to just click the empty action line. But how can I do this using the Python API so I can add the empty track?
Thanks in advance!

Use the API methods.
This can be done via low level calls.  Test script below, adds a new track "Foo", adds the action strip, starting at frame 1, using and named after object action.
When adding the track can specify the previous track to insert or append in different orders.
Only requirement is to  have reference to  an object with an action. Note adds empty animation data if none exists. Test against None to bypass
import bpy

context = bpy.context
ob = context.object

ad = ob.animation_data_create()

action =  ob.animation_data.action

if action:
    track = ad.nla_tracks.new()
    track.name = "Foo"
    strip = track.strips.new(action.name, 1, action)

This worked great, thank you!


text:
Can I reset the origins and parents of a object to normal X Y Z
Hello I'm new to blender and moving over from Maya. I have been trying to make a space ship in blender and been making some vents and panels for my space ship that I wanted to put on my ship. I used the snap to face tool for my objects to try and place them on the outside. The objects went on backwards so they faced the wrong way. I googled the problem and found a solution here Snap to face problem: object is flipped 180 degrees and snapped to inside faces
But then later on I wanted to scale my objects on the Y angel and of course now the x y z was wrong on the object so when I tried to scale it on the side it went completely the wrong direction... This is me trying to scale it in X direction with s + x and not working. https://gyazo.com/b88a0c4ba6928d2dad2c7deb1a3fd935 So I tried to google again to fix this but I couldn't find anything. I tried resetting the point with everything I know and I even tried to reset it with doing what I did in the first place but opposite and didn't work for some reason.
So if anyone know, please tell me. I tried to undo everything and go back to before I did this but need to get unlimited undos because i don't seem to have that yet. I realized too late that it would be a problem.
If I was not clear enough with what the problem is I'm more than glad to explain further.

before scaling, maybe try to apply the rotation so that the local orientation aligns with the global orientation?

Wow it was that easy! I been scratching my head on this for like 2 hours now. Yes that solved the problem thank you very much. Now I know til further. @moonboots

Hello and welcome. Instead of having users go through links and external sites please use the builtin tools to embed images in your post. See How to upload an image to a post? or GIFs

Before scaling, apply the rotation (CtrlA) so that the local orientation aligns with the global orientation.


text:
how do i unwrap multiple objects to secondary uv map?
let me preface this by saying my knowledge of blender and unity is limited.
i have here a mesh exported by a program that exports minecraft worlds (mineways) and im trying to bake lighting onto it in unity, however wherever there's a border in UV's i get nasty lighting, (that's using unity's auto generate lightmap uv's) all i need is a secondary UV map, which unity will use by default to bake lighting onto, what im trying to do is to select all of my blocks (all of which are separate meshes, and have separate materials) unwrap them all into a secondary UVmap, (to preserve the primary one for textures) and then save the .blend file which unity supports

Hi :). In the right UV Maps panel click the plus button. Boom, you have a second uv map. Now select it (click on it) an unwrap :)

@JachymMichal if i do that, it only adds a second UV to the first object i have selected, and once i unwrap to that UV it also unwraps over the primary UV of every other object, which i need for textures, so this doesn't work


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how to bend/transform own image
I'm new to blender. I don't know how to bend (transform) my png. I know how to do it with Objects like the monkey (found tutorial) but I don't know how to transform/bend my image into a something like a crown. Can please somebody help me? I tried it for 4 Days now and I checkt every tutorial. A friend showed it to me in Maya and it looked so easy but I can't do it on my own with blender.

Can you provide some more information please? are you trying to transform a UV texture? or an image in compositor?

Hello, as Zophiekat says we lack information on what you want to do, maybe show what Maya is doing, is your png supposed to remain a flat object or do you want an extrusion, etc?

hi, guys I can't believe you two answered me that fast. Thanks. I have a png and its just like a stripe made out of leaves. I want to turn it into a crown. I need to export it in DAE so I can put it into Sparks and make a filter out of it. My Problem is, that I just don't know how to transform the Stripe into a crown. There were many tutorials but not one of them was right for me. I know hoe to transform that (Mash)monkey now but not how to transform (curve) my stripe.

Try posting some images of what you've got, and what you are trying to achieve. See How to upload an image to a post? or GIFs

We lack informations, but if your image has a transparent background, you can map it on a cylinder like that:

If you're using Eevee, don't forget to choose Blend Mode > Alpha Blend in the Material > Settings in order to have transparency.


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Move collection including invisible objects
How can I move/transform a whole collection of objects, including invisible objects? I have invisible objects to facilitate boolean modifiers.
The popular advice to move a collection is to select all objects and then transform. However, this doesn't select invisible objects.
Another suggestion is to select all objects in the collection using SHIFT. However, I have nested collections with some levels of child collections, and it would be cumbersome to expand everything.
Is there a better way of grouping objects together, in order to use them as one in the scene?

Use a collection instance?

Hey :). Yeah, the fact that hidden objects cannot be selected is a bit frustrating...

Ah yeah collection instances seem to be the way to go! Then, I'd usually hide the original collection and place them somewhere far away in the scene? Or what would you recommend where to place the collection items themselves?

Well, collection instances solves a whole spectrum of things - but it doesn't really solve the "hidden objects" problem. Objects invisible in the collection are still visible in the collection instance! I found visibility settings under the object properties -> Visibility. If I deselect "Viewports", the object will be invisible everywhere. But that's quite cumbersome if I want to edit a hidden object anyway. Blender 2.9 by the way.

One way to overcome such a thing is this;
bpy.data.collections['target_coll'].objects.link(bpy.data.objects['issued_obj'])
bpy.data.collections['source_coll'].objects.unlink(bpy.data.objects['issued_obj'])

Object needs to be link to new than unlink from old but this is applicable if the source and target collections are known and to get this info;
source_coll = bpy.data.objects['issued_obj'].users_collection[0]

Additionally, if one want to use built in "Scene Collection" as source or target;
bpy.data.scenes['Scene'].collection.objects.link('issued_obj')
bpy.data.scenes['Scene'].collection.objects.unlink('issued_obj')

working on 3.6


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Hole at the edge leaves empty faces (boolean difference)
I am cutting a whole into a block using a cylinder and boolean difference modifier, exactly at the edge of a block. This cuts 50% of the cylinder from the block.
The problem with cutting a whole right at the edge is that it leaves empty faces in the cutout.
If I move the cylinder by a fraction away from the edge (either direction), the coutout will close the faces.
This does not seem to happen with a cube, although the 3D preview looks a bit confusing.
Is this expected or a bug? Is there a way to cut a cylinder while keeping the face closed? Or is it actually closed and just looks open?
I tried the "Solidify" modifier but that doesn't seem right to do for such a simple operation.
Blender version 2.9 here.

Boolean will break if there are intersecting edges at the cut. In this case there are the edges on both sides of the cylinder and edges of the object you are cutting. They are intersecting and Blender doesn't know what to do with them.

You can fix it by moving the cylinder by a small amount so there are no intersecting edges. If you want exactly half of the cylinder you can rotate the cylinder around z axis by a tiny amount.

It would be create it the boolean modifier was smart enough to reroute the intersecting edges. Maybe it will come sometime in the future but at the moment there will be many cases where you have to fix bad booleans by hand.

Thanks a lot for the quick help and advice!


text:
Unexpected behaviour on soft body collisions
I'm trying to get two soft bodies to collide in a zero gravity environment. The way I'm trying to do this is by having soft body one and two close to eachother, and having a third rigid body collide with the first soft body, so that it moves into the second.
The first part works well. Rigid body one moves into soft body one, bouncing it off and giving it some speed. But when soft body one collides with soft body two, it seems like the forces aren't equally distributed. Soft body two doesn't move, or barely moves, while soft body one bounces off soft body two hard.
Both soft bodies have the exact same settings, so I expected the forces to be about equally distributed after collision. What I expected was that soft body two would also bounce away with a little speed.
Just as a check I tested the same objects bouncing off eachother with gravity on. The first soft body would fall until it hit a plane, and the second soft body would fall until it hit the first soft body. This seems to work as expected.
Anybody have some insight?

The problem is not with the soft body simulation but it with the collision between the two - as the collision is only effectively 'one way'.
Consider the following simulation where the Cube is animated and the two spheres are separate soft body simulations (ie, where each object is a separate mesh, each with its own Soft Body modifier).

The Collision modifier on each of the objects tells Blender how the soft body simulation should interact with that surface - but it does not tell that surface how to interact with the soft body. This means when the cube collides with the soft body, the cube is not actually aware of the soft body but the soft body finds itself squashed against the approaching cube. This does provide a seemingly correct collision between the cube and the first sphere.
However, when the first sphere then moves across to the second sphere, from the first sphere's point of view it is colliding with a static surface - so it bounces off. From the point of view of the second sphere, however, it barely notices the presence of the first sphere (even though that first sphere also has collision enabled) since at any point in time, it is never any closer to the first sphere's surface than that surface came to it - and most likely bounced off that surface. So the second sphere does not react appropriately as it is effectively a completely separate simulation, seeing the first sphere as a non-moving surface that is close but never 'too close' to it. This results in the one-sided interaction where only the moving object seems to react properly.
The solution (providing you want the same soft body settings for all interactions) is to join (Shift+J) the two soft body objects together so that there is only a single soft body simulation in the scene. This means that the two soft bodies can interact and react with each other (since they are part of the same simulation) - instead of seeing each other as a stationary surface. This produces a much more realistic interaction :

Note that the above solution only works where it is acceptable for both bodies to have the same Soft Body settings - it is not possible to give each their own distinct soft body settings (for this we would either need to be able to properly link simulations (not possible with the Collision modifier at present) or we would need to be able to set different soft body properties for different parts of the mesh - perhaps by way of vertex weights).

Thank you for your great answer. It's disapointing that what I'm trying to do seems impossible for now. Will have to make all objects have the same soft body effects I guess!

Glad to be able to help. The interface between all of the simulations (rigid, soft, particles) is sadly lacking - and something I’ve had an interest in for quite some time. It would be great if there was some means of triggering an effect or recoil force based on the collision.


text:
Is it possible to restore default viewport condition?

This is default viewport condition after I made a '2d animation' project by ctrl+n.

And I scrolled mouse-middle button to zoom out viewport.
Then I wanted to restore default viewport condition(not similar but exactly same as first picture ) but I could not.
How can I do it?

Does this answer your question? - https://blender.stackexchange.com/a/217779/110840

@allen simpson Your answer is very good. thank you.

File>Defaults>Load Factory Settings. This will reset everything, like your addons, custom startup file too.

Then do not all things I have drawn disappear? I want only default viewport condition not new project.

@나미손 They will not disappear. This is different from loading a new project.


text:
What's the 'generate grease pencil' command in render view?

I saw something amazing in render view.
It was a command, 'generate greae pencil' in above picture.
But despite the execution of the order, nothing was done except that the name of g.p.object had been added in outliner(see below picture).

I thought that if I had done that command, a g.p.object like rendering image would appear in 3d veiwport.
But I could not find anything.
How can I use that command?

@susu Could you show me the resulting g.p.object? I have done as you taught me, but there's nothing but a g.p.object's origin

@susu thank you for good answer.

To create an image in the image editor and create a grease pencil object with it.
In the image editor create a new image (Image>New).
Change to Draw Mode.
Create your drawing.
Select Image>Generate Grease Pencil Object.
Switch to the 3d viewport, the grease pencil object should appear. The grease pencil object will be created with the lower left corner at the place where the 3d cursor is.


text:
Make Normals explicit with python
I do have a problem with normals in Blender.
I tried to recreate a script for Blender that we are using in 3Ds Max at work (the original script: http://wiki.polycount.com/wiki/VertexNormal#SetNormals_MAXScript)
What it should do (and does until normals are recalculated):
It copies the face normals to its vertex normals to get better looking bevels.
The Code:
import bpy
import bmesh

obj = bpy.context.edit_object
mesh = obj.data
bm = bmesh.from_edit_mesh(mesh)

for f in bm.faces:
    if f.select:
        fvector = f.normal

        for v in f.verts:
            v.normal = fvector

bmesh.update_edit_mesh(mesh, True)

How to use it:

Select the hole object.
Shading Smooth (no autosmooth)
Entering Edit Mode
Select all faces that should not be rounded (everything except the beveled faces)
Run the script

It works until I reenter the edit mode of a object.
Is there any way to stop Blender from recalculating the vertex normals?
Screenshots:

Does anyone has a solution for that?
Greetings and thank,
Tobias


text:
how do i enable "modifier" in blender 2.79?
I want to be able to morph some modeled pieces. I am unable to use the apply modifier control. It is disabled. I'm doing all that i can to re-enable it. Nothing is working. What am I doing wrong? How do I enable the Modifier?

Are you in edit mode? Modifiers can only be applied in object mode.

oh! i don't know. i'll look again. but each time i try to use it, it comes up with and exclamation point saying "modier disabled. i went to "user preferences" and turned on "3D modifier"

"modifier is disabled. skipping appy"

yes. i am in object mode.

Can you show a screenshot?

i can't do a screenshot. but, it's when i go into "modifier"  then i hit "add modifier" i choose one, then i hit "apply" it says "error" with an exclamation point. it says "modifier disabled".  i go into "user preferences" i enable the "3D Modifier" only ption i can find that says "modifier". it still doesn't turn on.


text:
Black shading appears in faces
I'm Modelling a car in which i'm getting a black shading while in rendered mode.
i've tried deleting the faces but still im getting those black shades.

it doesn't look like a normal problem, maybe you've smoothed in the left panel and enabled the auto-smooth option in the Properties panel > Data > Normals. So either increase or decrease the angle value, it determines the angle under which the smoothing happens, or simply deactivate smooth shading? It depends on what you want actually

ThankYou..I'll try that@moonboots

Try the following solutions

Maybe just because of the Smooth Shading applied for a low poly 3D model: Your model is currently at a low poly stage so change it into high res model or remove smooth shading until you add in more details to the model(maybe at least till you add subsurfs).
Normals Issue: Try recalculating the normals -> enter edit mode and select all then press Ctrl+N key
Duplicate Vertices or edges issue: Enter into edit mode and select all, then press W key and click on Remove doubles


text:
Animated texture that depends on camera perspective
I am making an animation where the camera moves around. I would like the texture of the object stay normal to the camera's view for each frame. (ie. equivalent to selecting "project from view" on each frame and then rendering each frame independently)
Please see the picture below for an example. There could be 1000s of frames so I don't want to be making a huge "baked texture" file.
What is the simplest way to do this?
Thanks!

Using WINDOW TEXTURE COORDINATE
Use a Window texture coordinate for mapping. Adjust Location, Rotation and Scale parameters of the Mapping node to make the texture fit the object borders.

Using UV PROJECT MODIFIER
Subdivide your cube a few times and unwrap it (I've marked seams and then unwrapped).

Add the UV Project Modifier. Set up your image texture, set the Camera as a projector. If the image doesn't display correctly adjust the Aspect values.

Why is your second animation so much smoother?

Because it has been rendered.

@PaulGonet - Do you know if it's possible to bake this projection?

@Neil Yes, in a way. There is projection paint, which works like the modifier except you unwrap the mesh from a certain angle and then use the project paint brush in texture paint mode.

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


text:
Selecting vertices within a box defined by exact coordinates
I have a mesh with lots of densely packed vertices.
I want to select all vertices within a bounding box defined by (x1,y1,z1) and (x2, y2, z2) exactly without selecting other vertices outside. Is there anyway to achieve this? (Add-ons will be fine)
It's too tiresome to use the mouse in some circumstances.

You can do this using python.
Open up a text editor in Blender and paste the following script.
import bpy, bmesh
from mathutils import Vector

# checks if a supplied coordinate if in the bounding box created by vector1 and vector2
def IsInBoundingVectors(vector_check, vector1, vector2):
    for i in range(0, 3):
        if (vector_check[i] < vector1[i] and vector_check[i] < vector2[i]
            or vector_check[i] > vector1[i] and vector_check[i] > vector2[i]):
            return False
    return True

def SelectVerticesInBound(object, vector1, vector2):
    # get the mesh data from the object reference
    mesh = object.data

    # get the bmesh data
    if mesh.is_editmode:
        bm = bmesh.from_edit_mesh(mesh)
    else:
        bm = bmesh.new()
        bm.from_mesh(mesh)

    # cycle through all vertices
    for vert in bm.verts:
        # check if the vertice is in the bounding vectors
        # if yes, select it
        # if no, deselect it
        if(IsInBoundingVectors(vert.co, vector1, vector2)):
            vert.select = True
        else:
            vert.select = False

    # update bmesh to mesh
    if bm.is_wrapped:
        bmesh.update_edit_mesh(mesh, False, False)
    else:
        bm.to_mesh(mesh)
        mesh.update()
    # trigger viewport update
    bpy.context.scene.objects.active = bpy.context.scene.objects.active

# get the active object from the scene
active_object = bpy.context.scene.objects.active

# ensure that there is an active object
if (active_object != None):
    # call the method to select all vertices in bounding box vectors
    # object             the object to operate on
    # vector 1           the first coordinate of the bounding box
    # vector 2           the second coordinate of the bounding box
    SelectVerticesInBound(active_object, Vector((0, 0, 0)), Vector((1, 1, 1)))

The coordinates for the two vectors are supplied in the last line, which calls the method. Input your coordinates, select a mesh in object mode and press Run Script or ⎇ AltP to run the script.
I have included comments explaning the code. Additional resources.

Get Vertex Positions
Properly get and update Bmesh objects
Select Vertices

Note: Somehow vertices don't get deselected when the object is in object mode. Maybe an experienced python coder can help us out here.

Fix for B3.0 - it looks like only three things had to be changed:
#36 bmesh.update_edit_mesh(mesh, False, False)
to bmesh.update_edit_mesh(mesh)

#46 active_object = bpy.context.scene.objects.active
to active_object = bpy.context.object

For it to work in Object Mode, also line #41
from bpy.context.scene.objects.active = bpy.context.scene.objects.active
to bpy.context.view_layer.update()

import bpy, bmesh
from mathutils import Vector

# checks if a supplied coordinate if in the bounding box created by vector1 and vector2
def IsInBoundingVectors(vector_check, vector1, vector2):
    for i in range(0, 3):
        if (vector_check[i] < vector1[i] and vector_check[i] < vector2[i]
            or vector_check[i] > vector1[i] and vector_check[i] > vector2[i]):
            return False
    return True

def SelectVerticesInBound(object, vector1, vector2):
    # get the mesh data from the object reference
    mesh = object.data

    # get the bmesh data
    if mesh.is_editmode:
        bm = bmesh.from_edit_mesh(mesh)
    else:
        bm = bmesh.new()
        bm.from_mesh(mesh)

    # cycle through all vertices
    for vert in bm.verts:
        # check if the vertice is in the bounding vectors
        # if yes, select it
        # if no, deselect it
        if(IsInBoundingVectors(vert.co, vector1, vector2)):
            vert.select = True
        else:
            vert.select = False

    # update bmesh to mesh
    if bm.is_wrapped:
        bmesh.update_edit_mesh(mesh)
    else:
        bm.to_mesh(mesh)
        mesh.update()
    # trigger viewport update
    bpy.context.view_layer.update()

# get the active object from the scene
active_object = bpy.context.object

# ensure that there is an active object
if (active_object != None):
    # call the method to select all vertices in bounding box vectors
    # object             the object to operate on
    # vector 1           the first coordinate of the bounding box
    # vector 2           the second coordinate of the bounding box
    SelectVerticesInBound(active_object, Vector((0, 0, 0)), Vector((1, 1, 1)))

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


text:
Dynamic toggle list
I'm trying to create a Panel to control showing and hiding a set of objects and their children. Creating a toggle to update an item's visibility is no problem, but I can't figure out how to avoid updating its children unless the toggle was pressed this draw:
class ShowItemsPanel(bpy.types.Panel):

def draw(self, context):

    # get all children of item container
    for item in bpy.data.objects['Items'].children:

        # set hide property
        self.layout.prop(item, 'hide', toggle=True, text=item.name)

        # childrens' hide properties are updated every draw; how to avoid this?
        for child in item.children:
            child.hide = item.hide

I considered creating a set of dummy BoolProperties with an update function as shown here, but I can't figure out how to apply this approach to my use case since the number of items is variable.
Can anyone point me to the best way to handle this type of case?

You cannot set properties like ob.hide from the draw method of a panel class. Related


text:
what are the things that can be done with python and cannot be done manually?
I am unable to learn python as I am not interested in that,but many people are saying that it is useful for effective usage of blender.so,what should i do now?

The ability to code using Python is useful, but not essential, to be able to use Blender.

You can't without a code select all object shearing different instances of the same material (f.ex. material, material.001, material.002 and so on). You can't remove custom shapes from all selected bones at once.So in general it's easy to perform actions on many objects at once and automate some actions, you perform a lot with python. I don't think it's absolutely essential to learn python to be a great Blender artist though. There are tons of people, who will gladly drop you some snippets of code to help you achieve stuff you can't without it.


text:
Smoke sim is not visible in render view unless I go inside the domain
Smoke sim is not visible in render view unless I go inside the domain? I added material for the domain too. I have done everything  and checked YTube[![material

What do you mean by "go inside the domain"? And where is your smoke domain located? In your screenshot I see lots of objects/collections with disabled viewport visibility. And what do you mean you have done "everything"?

First check that your scale is correct for the simulation you want. Simulations can be effected by domain size.
Adjust your camera end clip.
Select the camera then in the camera property tab. Under Lens there is a Clip Start, Clip end.  Increase the Clip end larger.
Also if you are using Evee, select render property then under volumetric there is a start and end field.  Increase end.
For the viewpoint in the top right corner select view, there is a clip start end field for the view,  increase End.


text:
Default value of slider via python script
I'm new to Blender and I'm jumping into the deep end with scripting. Is it possible to get the default value of a slider? For example, I'm after the anti-aliasing filter value.
# get current anti-alias setting
AA = bpy.context.scene.render.filter_size

# change anti alias value
x = 1.2
bpy.context.scene.render.filter_size = x

get the default value and revert back to it when finished
# AAdefault = bpy.context.scene.render.filter_size.default ???
bpy.context.scene.render.filter_size = AAdefault

Get default value
import bpy

bpy.context.scene.render.filter_size = 2.0
print(bpy.context.scene.render.filter_size)
# >>> 2.0
default_value = bpy.context.scene.render.bl_rna.properties["filter_size"].default
print(default_value)
# >>> 1.5

# bpy.context.scene.render.filter_size = default_value


text:
Render on transparency checkerboard options?
Is there anything that can be done about the grey/dark grey checkerboard background when rendering transparency in Blender 4.2?
I understand the significance that it's a visual cue...(rendering without a background) but can the colours and/or checkerboard size be changed? You know, for people who have problems with photosensitivity.

Sure. It's in the Preferences( F4  ->  P / Ctrl  +  , ), Themes settings, User Interface section under Transparent Checkerboard:

Beautiful! That's gonna save me a few headaches :)


text:
How to select and unhide objects with Python
In Blender 2.91.2 I'm able to hide objects from the viewport by selecting them first and then using
mySelection = bpy.context.selected_objects
for obj in mySelection:
  obj.hide_set(True)

However, doing the reverse, by selecting them on the outliner doesn't seem as trivial
I'm aware of this post, but still unable to formulate a solution.
I've tried using mySelection = bpy.context.collection but it seems a collection is not iterable.

import bpy

bpy.ops.object.select_all(action='DESELECT')

for obj in bpy.data.objects:
    if not obj.visible_get():
        obj.hide_set(False)
        obj.hide_viewport = False
        obj.select_set(True)


text:
Knife snapping to vertices
I'm trying to slice a cube corner to corner using snapping:

However, on closer inspection we've missed the vertex on the corner:

In fact we've added two more vertices. Bad cube, no biscuit!
I've tried using snap settings (see below) as well as using shift so that I don't introduce any new vertices into the mix and only allow the cut to occur at existing vertices.

Is there there a way to do this? Possibly increase the snap threshold? Or am I going about this all wrong?

Why don't you select the two verts and then hit 'J'?

@JohnEason This would help only in this case, not if you in other cases try to cut from one vertex to somewhere else on the edge. Although learning the shortcut J can be useful in many ways too, but since the question starts off with the Knife tool I focused on that. It's better to learn how to properly use the Knife tool. The important thing here, trying to enable Snapping does not work with the Knife, but there is an inherent snapping there.

Yes. I agree but in a simple case like this it's much quicker than using the Knife tool. The other problem some folks encounter is using 'F' to create the new edge instead of 'J' and then finding that they haven't actually cut the face!

@JohnEason Oh yes, confusing F and J is a problem for many, too. As I said, J would be useful and easy here, but this question showed me there is a lack of understanding how the Knife tool works. Maybe you could add your own answer, at least the last paragraph of the question invites to suggest other methods.

The Snapping tool is not used by the Knife tool. Instead, the Knife has it's own snapping method which does not need to be enabled.
If the green square indicating the knife's position is hovered over an edge this turns yellow to indicate, if you now click the cut will be snapped to the edge. If you move over closer to a vertex, a red outline around the green square will indicate the knife is now snapping to the vertex.

If you look at the bottom status bar while the Knife tool is enabled, you can see additional options for snapping: holding Shift let's you snap to the center of an edge, holding Ctrl makes the knife ignore the snapping. You will find other options there, too like angle constraint, cut through etc.


text:
Changing the default render path is not working
I'm trying to change the default render path in Blender 2.9 to something else. I've changed it in the preferences to my D:\ drive.

However, after restarting (and rebooting) opening a new scene the path is /tmp\
print(bpy.data.scenes["Scene"].render.filepath)

Is there another setting I'm missing?

Hello have you saved the preferences?

@moonboots I have done this, but it never worked for me. Still does not in 3.5.1, the path in the Output Properties can be saved with the startup file, but what sense makes the entry in the preferences then? I also have no idea when or where the Render Cache is used...

So it may be a bug?

@moonboots It might be, I never asked if someone else has this problem too, because I usually set individual paths for all my projects.

@moonboots Yes, I've saved preferences several times. This has been an on-gong issue for me.

OK I asked because there's an auto-save option but I'm not sure that it works

This is a default path for newly created Scenes.
To see it work, create a new Scene within your blender file.
(Simply restarting Blender won't show any changes, because it loads your Startup File with the old filepath)

Can you explain why saving preferences, quitting Blender, re-starting Blender (with a new scene) won't work.

Hi :). Not sure, it might be a bug in 2.9, but it works just fine in Blender 3.4.

Also keep in mind that restarting Blender won't automatically create a new scene. It uses your Startup File scene.

I did not know that you could change the Start Up File scene.

It's all in the maual: https://docs.blender.org/manual/en/2.79/data_system/files/startup_file.html ;)


text:
Sculpting problem
I downloaded a free 3d Blender Character and I wanted to change a little the body and face shape but i can t do anything. When I select a brush it does nothing. What can I do to change it? I am a 3d Modeling beginner.

could you please share the file or at least of it? https://blend-exchange.giantcowfilms.com/


text:
There is a way to add custom split normal use Python API?
I can't find a way to achieve custom split normal effect.
I want to use python (mesh normal/hard edge or soft edge) data collected from Maya then write to Blender mesh.
How to do it using the following Python API and how?
bpy.data.meshes[objName].normals_split_custom_set_from_vertices
bmesh module

Custom Split Normals
Elaborating on this answer and here
Test script. Run in object mode.  Switch to edit mode to see results.
import bpy

context = bpy.context
ob = context.object
me = ob.data
# visualize in edit mode
me.show_normal_vertex = me.show_normal_loop = True
me.use_auto_smooth = True
# normal custom verts on each axis
me.normals_split_custom_set([(0, 0, 0) for l in me.loops])

end up with custom split normals in each of the corner directions. Blue are the vert normals
# all custom split normals pointing up.
normals = [(0, 0, 1) for v in me.vertices]
# make csn's all face up.
me.normals_split_custom_set_from_vertices(normals)

all custom split normals facing up (0, 0, 1)
I am not aware if custom split normals can be accessed from bmesh.

really appreciate,  I got your idea, and to get a hard/soft edge effect, except setting custom normal split, what else I need? setting sharp edge?

I try it, and I think it is no need to mark sharp edge,  I get same hard/soft edge effect like same mesh in Maya.what's your idea?

@XuqiangZhang forgot to mention needs to be run in object mode.


text:
Connecting curve and plane
I want to connect a curve with a plane as shown in the image.
Actually I'm making a fancy chessboard and i want to make it's base.
I've tried bridging edge loops and selecting respective vertices & adding  face (it works but not proper shading as shown in images).
So can anyone please suggest some another method?

If I understood you correctly, You want this :

I would do the following :
Start from your "curved planes gird" :

Make sure every "curved plane" is merged with his neighbors by selecting everything with A → open the "Specials" menu with W and clicking "Remove Doubles".

Then, hold Alt and click on an border edge of the "gird" in order to select the whole contour :

Extrude down this edge loop by pressing E and Z to constraint the extrusion on the Z axis. Click to confirm the action.
Make the extruded loop perfectly plane via a "zero scale" on z-axis: S + Z + Numpad 0 and click to confirm.
Then fill the bottom face, either via F, or via CtrlF → Gird Fill which may allow you to make a correct topology.

In addition, I would make a shade smooth, then turn on the "Auto Smooth" in the Object Data area :

This will make the whole object look smooth while keeping the sharp edges like they're supposed to look like.

Thank you very much. This helped a lot. By the way did you made this video or it's available on the internet somewhere? Just curious....

I made them myself, there are plenty softwares to do that. I usually use ShareX or Screen to Gif.

1.Add a NURBS surface and use Alt C > to mesh in object mode;
2. Extrude vertices, join them with edges and make faces;
3. Use Array to make the board.


text:
How convert particle system to mesh blender 2.8
I tried convert my particle system to mesh but I don't have any convert button under modefier setup. What did I do wrong?

I have same problem with official 2.8 now It worked just once and now when I convert it all particles jump back to plane. I solve it just simply exported particles  as obj and all is fine

Edit: The convert button won't appear until you've set the render type to object and selected object to use from the sub menu. If you still don't have the option it could be 2.8 specific bug (it appears for me in 2.80.37)
One common setup to convert particles to mesh objects is to use metaball as the particle object. (Particle system, Render, object)
This way after you are done with your particle system you can convert it to mesh (because metaballs can be converted to mesh) This allows you to convert the particle system into continuous surface. The down side is that it gets pretty heavy on the pc if you want to have very granular definition (say for something like fluid)
Gleb Alexandrov did video on this titled
"Blender Tutorial: How to Create a Paint Splash in Blender"
You might also refer to this other post here:
How to convert particles to mesh
Which is basically the same thing but with just any object (but, for example, when using spheres every particle will create single sphere. Both methods have their uses)

ok i will watch this video, but why i dont have any problem in early blender version, i mean blender 2.79.


text:
Joined Head won't move with the rest of rig
I joined a head after I made a body for my character. and once I tried to move the head to make a pose the head refuses to move.

did you create the head after you parented the body to the armature? did you parent the head to the head bone?

first question Yes, and second question No.

Select your object and go in Edit mode, then go to the Vertex Groups menu in the menu Properties > Object Data, you'll see all the Vertex Groups of your mesh, they have been given the name of the bone they have been assigned to when you've parented with Automatic Weight. Is there a Vertex Group called by the name of your head bone? if yes, then select the Vertex Group, select the head vertices and click assign. If not, then click on the "+" button and create a new Vertex Group called by the name of the bone, then select the head vertices and click assign. It should work.

you can also switch your armature to Pose mode, the switch your object to Weight Paint mode, then select the bone you want to assign vertices to, then paint with the brush with the Add or Substract option enabled. Add will increase the influence of the bone on the part of mesh you paint, Substract will decrease it, red color will mean 100% influence, blue color will mean 0%.

Thanks, moonboots, but I'm having a hard time finding what you're talking about. Could you maybe upload an image showing where the object data menu is, please? It would be a super huge help, thanks again.

https://zupimages.net/up/18/25/bdx8.jpg


text:
Automatic weights deformation on character mesh
I tried rigging a character with automatic weights and did, but it deformed the mesh severely, I did remove doubles, recalculating normals, etc, but nothing worked. Any ideas for what the cause of the problem might be?

Hello and welcome to Stack Exchange. Since your question concerns a very specific problem, it would be helpful if you could upload your .blend file, so that we can have a look at it.

Sure, Here we go: https://drive.google.com/file/d/18YmSS687VcnuIRNudWTifcpGmRNIqFkQ/view?usp=sharing

That is the IK-Chain's doing. If you switch from Pose Position to Rest Position, you can tell, that your mesh is still ok.
This is however a very easy fix: All you need to do is adjust the roll of the bone that has the IK-Constraint on it. You do by selecting the bone in Pose Mode and the going to the Properties Window and Bone Constraints Tab.

thank you mate you really are a life saver;)

You are very welcome! Don't forget to mark the question solved. Well, if it IS solved, that is.


text:
How to hide lighting(like unchecking diffuse as in 2.79 ) from lamp but keeping shadows in EEVEE?
I want to add a light that cast only shadows not radiate light in eevee. In 2.79 blender internal there was a option with light, you can uncheck diffuse keeping shadows checked but in evvee how to do this?

Add another light in the same spot with negative power.


text:
How to change alpha value of all material in a single go?
I have a blend file in which all the materials alpha value is 0.
There are too many materials for me to change the alpha value manually to 1.
Is there a way I can change alpha valuec of all materials in a single go??

Try running this script
import bpy
for mat in bpy.data.materials:
    if not mat.use_nodes: continue
    for n in mat.node_tree.nodes:
        if n.type == 'BSDF_PRINCIPLED':
            n.inputs["Alpha"].default_value = 1

thanks you saved my lot of time

Based on top suggestion i made this script: import bpy for mat in bpy.data.materials: if not mat.use_nodes: continue if mat.blend_method == "BLEND": mat.blend_method = "HASHED" it works on blender 3.1


text:
How would I fix the moving position exactly to the part I want it to move?

See how on the image the positioning isn't correct. I'm talking about the white pieces see how far they are from those movers with arrows that means If I move I would have to move an extra. It also makes it impossible for me to rotate them to the exact way I want without spending 2 hours.

in blender every object has an object origin the transform manipulators are at the pivot point and the pivot point is at the object origin (you can change where the pivot point is), if you want to move the object origin go to the Object>Transform menu there you have a couple of options, origin to geometry should do the trick.

or shortcut shift ctrl alt C, and in 2.8 it will be Object > Set Origin


text:
How to uv unwrap a plane
Morph targets: A sphere shape turning into a cylindrical unwrapped sphere shape
This tutorial shows how to transform a plane into a sphere. However, it mentions UV unwrapping the plane. how am I supposed to do this?

UV unwrapping allows you to put a texture on your mesh, I guess if you use the method described in your link, i.e. folding a simple plane, you just need a basic unwrap, meaning U > Unwrap, but maybe describe your project more in details?

just explain how to do what he does in the image following "unwrap by pressing U". before that, he subdivided once, meaning the plane became four squares what is he doing in the unwrap image? also, Iam am using the accepted answer on the page.

what does change to face selection mean?

@cegaton: "Maybe that person will eventually learn how to write proper answers", could you please precise what you mean? You actually don't need to use Project from view, a simple Unwrap will work - and no need for face selection either...

oh ok didn't understand   ;)  Anyway, I think we lack informations about what Rishab wants


text:
Dissolving tool is doing really stupid stuff
I'm trying to model a Star Destroyer, from Star Wars. If you look up a picture of it, you'll notice that there are indentations along the sides where mechanical looking things and whatnot reside. I'm trying to recreate those by insetting a face, which adds this annoying little face:

However, on trying to dissolve the edges to get rid of it, it does not "merge faces" as the tool description says, it deletes a ton of unrelated edges, giving me this:

So what am I doing wrong?

can you explain better you issue, for better understanding?

When I try to dissolve a face that was added by insetting a different face, it deletes most of the inside of this mesh. I don't understand why this is.

dissolve vertices instead of faces, and also unselect the vertices from the edges, just select the inside ones.


text:
UV Mapping identical meshes on top of each other
I have an object with multiple identical meshes that I would like to use the same texture space for. When I unwrap the object, however, it maps each of them to a separate space. Is there a way to tell Blender to map them on top of each other, instead of having to manually move each one to the same space?

If the vertex orders aren't screwy, you can

In Edit Mode, P separate the identical components into their own objects
UV unwrap one of them
Back in Object Mode, with all component-objects selected and the unwrapped one active, CtrlL > 'Transfer UV Maps'
CtrlJ rejoin the components into one object.

That sounds like nearly as much work as just grabbing the meshes and moving them in the UV... I can't just group them together to unfold as one?

@APersonWhoDislikesWindows you could have a look at the various features of the shipped add-on Magic UV..  Perhaps  you could post up an example challenge at Blend Exchange?

If you hit U for unwrap and then R for reset it creates identical squares on top of each other. Its not exactly what you wanted but it works ok as long as you have an identical rectangle. I use this quite often.

Using magic UV and with simple identical meshes where each mesh is a single island, I use this workflow:
First of all enable UV-magic from Blender preferences>addons.
In the example, I start with a cylinder cut into 8 equal pieces. I also add a seams so that it can be properly unwrapped by blender into 8 equal rectangles. Note that the seam goes around each ring. In edit mode press A to select all and U 2 times to unwrap:

(I enabled display stretch overlay to make the UVs more visible in the screenshot)
Make sure island selection is activated, you might need to disable UV sync selection for this (the leftmost button):

Select all the islands you want to lay on top of each other and in Magic UV tab go to UV Maniuplation > Snap:
Set:

Snap: point
Group: UV Island
Target Point: you can leave this standard, user your 3D cursor to set the point where the UVs will group or set the point to the average of vectors. It doesn't really matter that much since you'll be able to move them around anyway.

Click snap to point

As you can see in the screenshot below, the meshes are now properly on top of each other and repeat 7 times:

I suppose for meshes with multiple islands, you would have to repeat this process for each island.


text:
Blender fails to load
I've just tried to launch Blender. Nothing has changed except for a recent Windows upgrade. When I launch Blender it hangs then crashes at the launch screen. I cannot get any version (2.20, 2.78, 2.79, 2.80) to advance past the launch screen - like, at all. I've been using Blender since the day Steve Jobs died so I'm no noob.

I've tried uninstalling and installing (many times)
Installing previous versions
Updating Windows and NVIDIA drivers
Launching from the installer and from the .exe zip file

Any ideas would be great? No error messages apart from the Windows (Not Responding) before it just stops.
Help!

Please have look at the related questions and the right side.


text:
Modeling Issue Bug or What?

When I try to edit my model
Object just turn into wireframe mode
It happens also when I selects other object and edit it.


text:
Painting in blender

Any tips to avoid this distortion in blender?
Or should I use other software.

My first point to check would be the uv map, could you provide some more info to make it easier to find the problem. While more screenshots with at least the uv map and maybe info about modifiers on the object could help clear the situation, the .blend file would allow a more detailed inspection of the problem.

Yes, please include screen shots of your tool settings and the UV mapping, as well as indicate what kind of occlusion you are using. Also, have you tried painting in the Image Editor on the offending faces, and have you tried using Face Section Masking to isolate the problem areas and drop paint with the Fill tool?

Thank You for response I think I got the point for texturing this!


text:
Why isn't my textured UV map showing?
I'm trying to texture this 3D model of a squirrel, and I want to see how my eye placement looks on the model. I imported the textured UV map into blender (see the lower window), but it doesn't appear on the 3D model (see the upper window). How can I get my textured UV map to show up?

Make sure your viewport is set to texture view.

Oh wow, such a simple fix! I'm completely new to blender, so thank you!!


text:
How to find and delete extra UV layers on many objects?
I have a scene with a few thousands objects and part of them, randomly, have 2 or 3 UV sets. I need to keep just the active UV because when exported in fbx they get mixed. Thanks!

Script
Removes non active uv layers from all meshes in blend.  As with all scripts that remove things, save first.
import bpy

for me in bpy.data.meshes:
    uvs = [uv for uv in me.uv_layers
            if uv !=  me.uv_layers.active]
    while uvs:
        me.uv_layers.remove(uvs.pop())

Removes all uv layers not marked active render.
import bpy

for me in bpy.data.meshes:
    uvs = [uv for uv in me.uv_layers
            if not uv.active_render]
    while uvs:
        me.uv_layers.remove(uvs.pop())

Thanks! works great but I realized that "active" means highlighted in the uvmap list but wanted to keep the "active for rendering" one. Can you tell me what to change?

NP added edit to remove all uvs not marked active_render

If you really have thousands of objects than use code. For single use you can delete them under the Object Data Tab in the Properties Panel. Go into edit mode, select your mesh and click on the different UVMaps to figure out which one is empty. Hit the minus button to delete it.

Thanks but I know how to do it manualy. Is just that I can't do it for all selected objects from the interface.

For people who find this thread when searching for a way to simply delete UVs on all objects. I edited batFINGER's script to do just that.
import bpy

for me in bpy.data.meshes:
    uvs = [uv for uv in me.uv_layers
            if uv !=  me.uv_layers]
    while uvs:
        me.uv_layers.remove(uvs.pop())


text:
Is it possible to set/manipulate vertex colors from geometry nodes?
Is there a way to output floats or colors into a vertex color layer from geometry nodes in Blender 3.0 or 3.1? Thanks!

yes you can. Example:
I use the position to create a color (red, if z > .5)

result:

I was sure that the Output Name in the node properties is the name of the attribute. And seeing in your images Value vs Col I realized the issue was that the Modifier List addon I am using does not show the Output Attributes in the modifier pannel. Once disabled that addon everything fell into place. Thanks!

You are welcome


text:
Diffuse - old school self-illuminated material
I'm trying to create a material similar to the properties (old) 3ds Max "self illuminated material", in that it would ignore any lighting and the values of the diffuse texture would be what you get in the render. Just to avoid confusion I'm not after a glowing "illuminated" material.
I've made a simple Elmer cube to explain:

I was hoping the colours would exactly match that of its texture map:

But if you look carefully the colours are close matches, but not exact. (Compare both the white and orange squares)
This is the material:

Hello have you tried with an Emission shader instead?

Yes, like this? Yes, same results as before

I can't see any difference: https://zupimages.net/up/23/21/3gmh.jpg

It was the Colour Management setting that were altering the colours!

Connect the Image Texture directly to the Material Output (no shader in between). IMPORTANT! - Make sure to change the View Transform (under Render Properties > Color Management) from Filmic to Standard:

To get rid of all the shading, you can delete the Principled BSDF in your material and instead connect a simple RGB node:

Proof: Color is Set to R:0.5, G:0, B:0 in the Shader.

Rendered image also has R:0.5, G:0, B:0 (right-click on any red pixel in the Image Editor)

In your case, you can simply connect your texture's Color Output directly to the Surface Pin of the Material Output Node.


text:
Change alpha background grid colours
I suffer from photo sensitivity issues, is it possible to change the background grid colours when rendering to a transparent image? Preferably both shades to a mid, flat grey so as not to induce migraines.
My interim solution is to switch Color and Alpha to just Color on the Display Channels tab.

You can change the Transparent Checkerboard under Preferences > Themes > User Interface > Transparent Checkerboard:


text:
Create addon with no initial keyboard shortcut assigned
From the example here I can create the addon which allows a custom key map
if kc:
    km = wm.keyconfigs.addon.keymaps.new(name='Object Mode', space_type='EMPTY')
    kmi = km.keymap_items.new(AddCube.bl_idname, 'T', 'PRESS', ctrl=True, shift=True)
    addon_keymaps.append((km, kmi))

I can change the initial keymap to ALT + 0 with
    kmi = km.keymap_items.new(AddCube.bl_idname, "ZERO", "PRESS", alt=True)

But how to change it so it's not assigned to anything, yet has the option to assign a keyboard shortcut.
I tried
    kmi = km.keymap_items.new(AddCube.bl_idname, "", "PRESS")

but that resulted in an error. And this:
if kc:
    km = wm.keyconfigs.addon.keymaps.new(name='Object Mode', space_type='EMPTY')
    addon_keymaps.append((km))

just loses the Assign Shortcut context option entirely.

Wild guess but I think in order to be able to assign a shortcut to an operator it must be used somewhere in the UI, maybe try to add it to a dummy panel ?


text:
Centre face dots in Xray mode
Being new to Blend 'n all... In Blender 2.91, whilst modelling, I've suddenly noticed dots in the centre of faces (Edit mode) when Xray mode is on.

I'm not sure what I clicked/pressed to get them there. I've tried toggling things in the Viewports Overlay menu but they still persist.
I would like to switch them off and still keep X ray mode on. Is this possible?

They are there so that you can easily select a particular face when you have multiple faces overlapping. If you check, you'll find that you can click anywhere on a face to select it in solid view, but you have to click on the centre dot of a face to select it in xray mode. That makes it a bit easier to select a particular face from several overlapping ones.


text:
About the omission cube of the Grease pencil in Blender v2.8

Here are the differences between my viewport and the Tutorial's viewport.
Q. How to show the small orange cube and the object data?

The 3 axes arrows has become the orange cube, and the pen icon has become the green squiggly line.
The icons have been changed since the tutorial was recorded in the early stages of the Version 2.80 and the icons were not final at the time. But you should find the same information in these submenus.
Although I think there has been changes to how the grease pencil object data works so you might see things arranged differently.

Thank you for your comments. How does the green squiggly line look like??

Most important is the object data still cannot be found that I am not able to edit the layer of the brush.....

There is only one green icon on your screenshot. It's located exactly at the same place as the pen icon in the screenshot from the tutorial

Found the object data finally. Thank you so much for helping!!


text:
Why is my fluid simulation mesh wireframe in solid view?
I haven't used blender in a few years, and I've gone back to it to try fluid simulation, so I'm a bit of a noob...
I'm using 2.9, I've done my fluid simulation, but it's just showing as a mesh in the solid view.  Is this what it's supposed to look like in version 2.9? All the tutorials and on older versions I used the fluids was grey in solid view once the mesh was baked. Also why does it stick to itself like some kind of ooze instead of water?
https://drive.google.com/file/d/1sseUag-XJOKUFLwkbFl2hNw4v-gIzf6V/view?usp=sharing
Thanks

The Fluid sim in Blender seems to set the viewport display to Wire. Changing this back to solid will display your mesh as expected.
Object Data -> Viewport Display -> Display As

2.9 is using MantaFlow which is different from older versions.
Make sure you changed the type to modular, and turn on the resumable setting. Once you're done, bake the fluid simulation. The baked animation will show as a halo particle. Then, check the Mesh option and bake the mesh. You can mess with the resolution for better result.


text:
Custom binary exporter, is this script possible to do?
I'm trying to create a binary exporter that does this in sequence:

Write fixed hex header, 8 bytes: "01 00 00 00 01 00 00 00"
Write custom hex ID1, 8 bytes
Write Custom hex ID2, 8 bytes
Write Custom hex ID3, 8 bytes
Write Custom hex ID4, 8 bytes
Write Custom hex ID5, 8 bytes
Write Custom hex ID6, 8 bytes
Texture number ID, 4 bytes uint Little endian
Write fixed hex, 8 bytes: "00 00 00 00 00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 80 3F 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00"
Write mesh 1 total lenght, 4 bytes uint little endian. *calculated by: ( 8 * polygon number) + 32 * total vertex )
Polygon 1 vertex data:

A) Write Custom hex ID7, 4 bytes uint Little endian
B) Write polygon 1 total vertex, 4 bytes uint Little endian
C) Write a total of 8 int floats, each one 4 bytes Little endian: X Y Z Xn Yn Zn U V

Continue by appending polygon 2 vertex data in the same format and so on

I am new to Blender and scripting, is this possible to do or it is too complex? :)

Blender uses python. There is no reason I can see to make  exporting its data to binary as described above or to fooble gimblewads  impossible. Too complex..? depends on your skill with python file IO.

Then I'll try doing it step by step thanks! Is there any noob-friendly tutorial on binary writing?


text:
Render image rendering incorrectly with a checkered pattern
I am learning Blender and following some Udemy courses. I added some materials to the model and in the render viewport, it looks completely fine in that nothing looks broken.

When I add a camera to the scene and try take a render image, it's almost like the materials are missing and it comes out all spotted and checkered looking.

Does anyone have an idea what might be causing that to happen?

Hello :). These look like overlapping faces. Perhaps you have another (same) mesh only visible in renders.

Oh goodness, I hate being beginner at things lol, that was exactly it, I didn't even think of that. I had a backup model disabled in the viewport but not in the render. Thank you @JachymMichal

Happens all the time :). Glad you made it work.

What @Jachym Michal said is correct. Press ALT H in the viewport, your second object should appear, otherwise search in the outliner.  Btw. this irregular pattern of triangles and weird stripes is called z-fighting, where z is the distance to the camera, it means 2 faces occupy the same space and the camera has troubles deciding which one to show in each sample.


text:
Render animation in png's give same frames
When I render an animation in multiple png's blender outputs all the frames. The only problem is, all the png output files are the same.
Thanks in advance

thx for the file, found the problem:
two things:
1. bake cloth simulation: "Bake All Dynamics", otherwise eevee wont simulate it as  Blender would do it by pressing play in 3D View.
2. Your Render step in the Output-Menue was at 1000, so you would only get 1 frame. Just put it to 1 and everything should work fine.
just for completness: i used "blender-2.80.0-git.957b4547aeeb-windows64" build to test it.

I have 1 camera and the camera is pinned. It's a flag animation. it's for a school project.
Here is a link to the file. https://drive.google.com/open?id=13wAES2o-U6B-OIlS-tKU6wnmrDjDWR16

updated the answer


text:
Measuring the distance between an inclined plane and another object
let's just say we have a sloping level, like a ceiling. Then we have objects, like cubes, that hang from the ceiling. I wonder if there is any simple way to see the distance between the roof and the cube. Sure, i can measure it, but if there are, say, 10,000 cubes, measuring and calculating every distance doesn't seem nice. I almost know it's not possible, but I had to ask... Below is a picture that may somehow explain the problem. Thank you.

If all the cubes are the same height, it's pretty simple trigonometry. If you have say, 4 different possible heights for cubes, and all 4 cubes are at one of those levels, you just have 4 simple trigonometry equations to do

Basic trigonometry, yes. But if the ceiling would be 8m high and the size of the ceiling would be 7m x 8m. Then we hang from random points, for example, 5000 3x3x3cm cubes at different heights. Some points include several cubes. It would be nice if you could see the distance between the ceiling level and the cube by clicking on the cube. Like you can see objects location in transform panel.

It is possible with Geometry Nodes:

What I'm doing is creating a line with two endpoints, then using a Raycast node to move the second vertex straight up until it hits a face in the target object. Be aware that the distance is calculated from the object's origin. This could be further improved to suit specific needs by moving the first vertex an appropriate amount (to measure not from the origin, but the top face, for ex). You could also measure horizontal distances (or any slant in-between) by changing the Raycast ray direction.
Most important part, the actual generation of the number is done with Ginyumbi's (free) Attribute Viewer node group:

To use, you can append the NodeTree "LaserMeasure" from the attached file below. You also need to download Ginyumbi's attribute viewer and append and link it as seen in the full node screenshot.

Wow! This is more than great! I think this Geometry Node stuff can really be weird some times. I really appreciate your reply. And how well done and beautiful that reply is. Thank You!

You're welcome. What do you mean with "weird"?

So many absolutely strange things you can do. Some times those node groups just make my head hurt. Powerful stuff. That's what I meant. Thanks again.

Easy just use Measurelt add-on that is included with Blender. These are the steps to do:

First enable the add-on from Preferences.

Click N key to show side menu and you find it in View tab.

Then enable showing the measure in the viewport.

Select first the plane or the ceiling and then the cube and click Link under Add Measures.

The add-on will measure the distance between origins of objects in XYZ.

I hope I helped you. The Measurelt docs

I'm fine, thanks for asking. Thank you for your answer. I know the MeasureIt tool, but unfortunately it doesn't solve my problem. I don’t need a origin point to origin point measure. Can't it be possible to change the x-axis angle in my case? How great it would be if there was a python wizard who could turn x-axix 20 degrees.

I thought in python code that could help you, it is about  drawing a line from a face of an object that be in your case cubes and choose then the direction up or down of the cube and when the line hit a surface the face of the plane it will stop in this case the ceiling is the plane and then measure the length of line. This could help with some edits and it could be an add-ons , you just need one to code it.


text:
Unable to render material/texture using the script
I am new to blender and trying to render this file. Trying to render using script gives a very different result (everything purple) as compared to what I see in Blender GUI. What am I doing wrong?
Here is the script I am using
import os
import bpy

bpy.ops.wm.open_mainfile(filepath="materials.blend")

VIEWS = 1
RESOLUTION = 200
RESULTS_PATH = '.'
DEPTH_SCALE = 1.4
COLOR_DEPTH = 8
FORMAT = 'PNG'
RANDOM_VIEWS = True
UPPER_VIEWS = True
CIRCLE_FIXED_START = (.3, 0, 0)

fp = bpy.path.abspath(f"//{RESULTS_PATH}")
if not os.path.exists(fp):
    os.makedirs(fp)

# Render Optimizations
bpy.context.scene.render.use_persistent_data = True

# Set up rendering of depth map.
bpy.context.scene.use_nodes = True
tree = bpy.context.scene.node_tree
links = tree.links

# Add passes for additionally dumping albedo and normals.
# bpy.context.scene.view_layers["RenderLayer"].use_pass_normal = True
bpy.context.scene.render.image_settings.file_format = str(FORMAT)
bpy.context.scene.render.image_settings.color_depth = str(COLOR_DEPTH)

# Background
bpy.context.scene.render.dither_intensity = 0.0
bpy.context.scene.render.film_transparent = True

# Create collection for objects not to render with background
objs = [ob for ob in bpy.context.scene.objects if ob.type in ('EMPTY') and 'Empty' in ob.name]
bpy.ops.object.delete({"selected_objects": objs})

def parent_obj_to_camera(b_camera):
    origin = (0, 0, 0)
    b_empty = bpy.data.objects.new("Empty", None)
    b_empty.location = origin
    b_camera.parent = b_empty  # setup parenting

    scn = bpy.context.scene
    scn.collection.objects.link(b_empty)
    bpy.context.view_layer.objects.active = b_empty
    # scn.objects.active = b_empty
    return b_empty

scene = bpy.context.scene
scene.render.resolution_x = RESOLUTION
scene.render.resolution_y = RESOLUTION
scene.render.resolution_percentage = 100

cam = scene.objects['Camera']
cam.location = (0, 4.0, 0.5)
cam_constraint = cam.constraints.new(type='TRACK_TO')
cam_constraint.track_axis = 'TRACK_NEGATIVE_Z'
cam_constraint.up_axis = 'UP_Y'
b_empty = parent_obj_to_camera(cam)
cam_constraint.target = b_empty

b_empty.rotation_euler = CIRCLE_FIXED_START
scene.render.image_settings.file_format = FORMAT
scene.render.filepath = fp + '/r_0'
bpy.ops.render.render(write_still=True)  # render still

Output of blender --background --python script.py

Screenshot of Blender GUI

Looks like you don't have any HDRI map for the World shader. Use one.

@Carlo - Why do I need a world shader? I am not concerned with background or anything, it is the material of the spheres that is not getting rendered

You are using a script to render the scene, so all the scenes settings are applied, world shader included. I don't see any line of codes changing that. Who set up the file used a world shader with a texture that you are missing. The file is "forest.exr". You can just get rid of the shader if you don't need it, but if you don't, it will use what is currently defined.

@Carlo - Got it. Thanks a lot. This was very helpful

I'm glad it was useful.


text:
Seal edge of mesh
Have used a shrinkwrap to make a mesh and trimmed of the bits I didn't want, however this has left the edge very messy and full of holes. I could go round the edge and tidy it up manually but this would take a very long time. Is there a simple fill all the holes and make it solid again?
Thanks

I'm assuming you're just trying to fill in the holes. To do this, select the edges around the holes (use Shift+Alt+Right Click) and press F to fill them in.

This is a small part of a very large mesh. I have started going round the edge and doing manually but was really wandering if there was a quick, easy automated method.


text:
How do I change the Blend Node to Vertical?
In my script I have added a Blend Node (in the texture editor) and I would like to define the direction of the gradient.
blend = tex_tree.nodes.new('TextureNodeTexBlend')
 blend.location = (0,100)
 blend.use_flip_axis = 'VERTICAL'
I thought adding the .use_flip_axis = 'VERTICAL' would work but it says it has no attribute use_flip_axis
What am I missing?..

I guess the API isn't finished yet or this is a bug @Darkfall You can test it using the Console and you will see that there neither is progression nor use_flip_axis available. But it should, according to the API: https://docs.blender.org/api/current/bpy.types.BlendTexture.html?highlight=use_flip_axis#bpy.types.BlendTexture.use_flip_axis E.g. all properties for the Output Node are available.

@brockmann, so should I report as a bug and hope they fix it?. In the mean time, could I use a rotation right after the Blend node?. It seems the rotate node is different in the texture editor than in the compositor.. It has a value for "Turns" not degrees..  I am not sure how to use it properly..

I didn’t test ,but looks like it’s a property of the texture and not the node. See if tex_tree.use_flip_axis does it.

@AFWS I tried and gave the same message,,

You need an object of type BlendTexture to set use_flip_axis, however the node is of type TextureNodeTexBlend. Seems to me that brockmann may be right and the API hasn't been properly updated for this node. https://docs.blender.org/api/current/bpy.types.BlendTexture.html https://docs.blender.org/api/current/bpy.types.TextureNodeTexBlend.html

@rjg so the code I wrote should work but it hasn't yet been updated?.. That being so, for a work around how can I use the Rotate Node in the Texture editor? It seems like everything I try does nothing.. it has a value for Turns not rotation..

@Darkfall yes and no. An instance of the node should of course provide access to all settings, but currently that's not the case for the Python API. Yes you can use the Rotate node. The Turns parameter is part of the inputs and can be set like this, for example bpy.data.textures['Texture'].node_tree.nodes["Rotate"].inputs["Turns"].default_value = 0.5

@rjg ok thanks for the Information! and thanks to all of you guys taking the time!!..

I'd report as bug. Doesn't seem to work in 2.79 either ,but it should. Works if not using nodes bpy.data.textures["Texture"].use_flip_axis = 'VERTICAL' ,but not this bpy.data.textures["Texture"].node_tree.use_flip_axis = 'VERTICAL'


text:
How can we create a Bar code with the Texture Node Editor?
I had seen a post about how to create lines but one of the Answers by Lemon was excellent.. He used the Shader Node Editor to create a Barcode Generator.
Here is the Link: How to make a barcode like stripes texture
I would love to be able to recreate this within the Texture Node editor. I tried to adapt it but it's not the same..

Blender 2.8x 2.9 has any Texture node system? Or are you looking for 2.79 creation?

waaow!! here is a zany bar code shader for eevee simpletons such as i

The question refers to the Texture nodes editor: https://docs.blender.org/manual/en/latest/editors/texture_node/introduction.html, not the shader editor.

This is good But I need it to be in the Texture Node Editor not the Shader Editor..


text:
Broken Add-on (only for one person though?)
So, I have been trying to create an add-on and with help from the community and lots and lots of snippets and videos, I am up to version 1.2.
Over the last few versions I have had a few thousand people download the add-on, but now one person is having trouble with it.
For him, the panels open but show nothing and when he checks the Info, it shows an error.

Now I know for sure that the code it mentions in the error is slightly broken anyway.
It toggles the information text.
The error points to line 2935 ?
but this same script works for everyone else, why would this now happen to this person?.
He is using the same version of blender as I am (2.80) and is also using a Windows, so there should be no difference.
If someone could help me figure this out or have suggestions I would greatly appreciate it.
I could also post the full code if that helps or link to it here

Here is the error message followed by the section of code around line 2935:
Traceback (most recent call last):
  File "C:\Users\ryanl\AppData\Roaming\Blender Foundation\Blender\2.80\scripts\addons\Darkfall VFX Nodes1_2.py", line 2935, in draw
    icon="TRIA_DOWN" if obj.expanded else "TRIA_RIGHT",
AttributeError: 'NoneType' object has no attribute 'expanded'

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

        box = layout.box()

        row = box.row()
        row.prop(obj, "expanded", # Line 2935
            icon="TRIA_DOWN" if obj.expanded else "TRIA_RIGHT",
            icon_only=True, emboss=False)

It is possible that the user has put Blender into a state where context.object could be None by having no selected objects. For example, if a user deletes the selected object, there will be no selected object. It could also be that this is a side effect from another addon (one that deselects all objects, for example).
I am able to reproduce this error by starting with a new .blend file and deleting the default cube. I am also able to reproduce the error by running the following script in the text editor:
import bpy
bpy.context.view_layer.objects.active = None

You may want to handle the case where context.object is None. One way to handle this is by adding the poll class method to the panel. The draw method will only run if the poll method returns True.
    @classmethod
    def poll(cls, context):
        return context.object is not None

EDIT: I took a closer look at your script. The only reason an object needs to be selected is because the expanded property is stored inside of an Object. The object is not used elsewhere in drawing. I would consider a small redesign so that the property is stored somewhere else so that it is not necessary for the user to have an object selected. An example could be to store the property in the Scene object. Here is an example for how this could be done:
class Sub1Panel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "clonepanel"
    bl_idname = "OBJECT_PT_clone"
    bl_space_type = 'NODE_EDITOR'
    bl_label = "Clone Node"
    bl_region_type = "UI"
    bl_category = "Darkfall VFX Nodes"
    bl_options = {'DEFAULT_CLOSED'}
    bl_parent_id = 'OBJECT_PT_toolseffect'

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

        box = layout.box()
        row = box.row()
        row.prop(scene, "Sub11Panel_expanded ",
            icon="TRIA_DOWN" if scene.Sub11Panel_expanded else "TRIA_RIGHT",
            icon_only=True, emboss=False
        )

        if scene.Sub11Panel_expanded:
            row.label("label")

def register():
    bpy.utils.register_class(Sub11Panel)
    bpy.types.Scene.Sub11Panel_expanded = bpy.props.BoolProperty(default=False)

def unregister():
    bpy.utils.unregister_class(Sub11Panel)
    del bpy.types.Scene.Sub11Panel_expanded

Ah, ok I understand now thanks! @RLGUY So if no object is selected then that's why it does not show. Your suggestion of adding the Poll Class method will only remove the panels unless something is selected though right?. So instead of seeing the blank panels, they won't see any panels at all. I see why this is a rare problem because most users open a new project and switch to the compositor, thus the default cube is already selected. Adding the poll is a good idea but I still need to let them know not to delete the default cube.. Thanks again for the information!..

No problem! I took a closer look at your script and noticed that with a small redesign, you could avoid the requirement of a user needing a selected object. I have added an edit to the end of the answer.

thanks that works for one panel "The Clone node" panel. How would I implement this for the other panels?.. do I just do the same thing? i need to change obj to scene then add the if scene.Sub11Panel_expanded: part. So I need to change the name?.. Also for the Register and unregister? I am a little confused, because Sub11panel is the Render Panel.

You can implement the other panels by registering more properties (one for each panel) and following the same pattern as the Sub1Panel example script. For example, you could register Sub1Panel_expanded, Sub2Panel_expanded, Sub3Panel_expanded, ... and use them as the expanded variable for the corresponding panel.


text:
UV unwrap creates a weird single edge result
I have a mesh which was decimated and UV unwrapped in zbrush, brought into blender to pack and optimize the UV's. Turns out, one of the islands is messed up and streched. (Sometimes this happens with zbrush meshes, normally I just select the problematic island and unwrap it again in blender, normally works well)
this is what came out of zbrush, streched and bad:

When I try to unwrap it again in blender, this is what i get, super weird, only 2 edges?:

I'm out of solutions at this points and can't figure out what goes wrong here. I've tried removing doubles or marking the problematic island's border as a seam again and unwrapping, but nope.
Any suggestions are appreciated
Cheers

What kind of Unwrap method you used? Snapping enabled? Have you tried to reset UV's? ... for this king of topology it has to be pain to UV's :)

yes it's a huge pain! i'm just doing "U > unwrap". are there other methods of unwrapping in blender? I have tried resetting and doing U > unwrap again but here is the result: https://i.imgur.com/1POvH3G.png  that massive triangle is the whole mesh, and i think the initial problematic part is that weird edge again. what the hell is going on here? :D
also, i don't know about snapping.

When you press U you get bunch of options check the reference Manual

Ah damn I'm dumb. Just using the "project from view" worked really well - don't know why I never though of that! Thank you.


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Rendering problem
I have a problem with the rendering of my scene, instead of having a nice gradation as on the real time rendering, I have this result, with plain colors, it's very weird, I don't know the reason for this, can you please help me ? Thank you so much (the render engine is Eevee)

Check if your Subdivision Surface modifier has the same number of subdivision for the render.

That was it! Thanks :))


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Light Presets .exr
I would like to install light presets for Blender to automate my lightning in my scenes. I have some .exr files (from Greyscalegorilla) but I don't know how to do it on Blender to make it work. Can someone help me? Thank you

You can install additional environment lights from the preferences:

after files are chosen:

You can now selected them as new environment maps:

Sweet, I didn't realize I can add new HDRIs this way :)

Greyscale Gorilla Presets are made with C4D Lights and Image textures. What you can do is use the EXR Files, which are HDRI's, under the "World" to light a Scene. Check this video from Blender Official Channel for more information on World Enviroment: https://youtu.be/RRilLLyyn1Y?t=98


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PNG darker that the actual rendering
when I save my image as a png, it appears darker than the original rendering, or at least, the colorimetry is not the same. Does anyone have any idea what it is? Thank you

Related: https://blender.stackexchange.com/questions/164677/images-as-emitters-constantly-come-out-dull-white-emission-not-actually-white/164679#164679

There's possibly a setting you can change in your render settings under colour to fix this. Otherwise, since you are on mac and using image preview you can always just click the pencil and then adjust settings pyramid button to correct the output.

Duplicated question. Colorimetry is not the same


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Colorimetry is not the same
I wanted to know if you know why the colorimetry of the image is not exactly the same when I save the image of the rendering, my settings in the save are however the Blender standards (RGBA, Color Dept 8, Compression 15%). Thank you very much for your answers :)

Maybe check the Render > Color Management settings? Or share your file: https://blend-exchange.giantcowfilms.com/

You are on an Apple device. The chances are your display is not sRGB, so using the sRGB device would be wrong, and all of your work accordingly wrong.

Hey, how can i change the display setting to sRGB ?


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Unwanted black lines
Can you help me by explaining how to get rid of those black lines in Blender? Thank you very much.

Could you show us some screenshots of your material setup and maybe share your blend file via https://blend-exchange.giantcowfilms.com? It's hard to tell exactly what's going on from one single render.

That's either due to too few transmission (transparent) passes or lacking geometry. My guess is the former, increase the bounces for the two in the render settings.


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How to use "Loop Cut" and prevent interruption / disconnection
I am in progress in creating a 3D object but I encounter difficulties.
How to prevent interruption / disconnection when using the "Loop Cut" tool?

Why here is not working?

And here is working?

loop cut will only happen if it crosses quads, so maybe here you have a problem of ngons or inner faces, if you don't find please share your file: https://pasteall.org/blend/

I don't know exactly as I don't have your model but by seeing the gif I guess there is some problem with that face. The shading of the face does not look proper to me. I have marked that face in the image below
Probably some edge/vertex is missing and that can be the reason why it is not showing for those faces


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Fix Particles not intersect with each other Non overlapping
I have to create a scene with some particles, but I encounter difficulties...
The particles are intersecting each other.
I have attached here the .blend file: https://drive.google.com/file/d/1Oq7iXtxP0skwezAeAp35UBQaVBzRYGO6/view?usp=sharing

particles are always intersecting. They are no rigid bodies. That's normal default behaviour. If you wanna have particles, which can collide with each other, you can try the free molecular add-on.

https://blender.stackexchange.com/a/166866/2214


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Transparent Material - so that you can't see what's next object through it - Similar with green screen
I am wonder if it possible in blender (cycles) to create an "fake" transparent material, so that you can't see what's next object through it and what you will be see is only transparent (alpha channel), something similar with a green screen.
Here it is an example with what I am trying to say...

Hi :). This might be a good case for the holdout shader

By adding the Holdout shader will make things work

If I understand your question correctly, this is an appropriate solution. Just be aware that everything behind the holdout object will disappear and will be transparent there.


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Random colors on single objects and only for selected faces
I want to have random colors for each face individually, it is possible?
How?
Now each faces have a same color...
I have attached here the .blend file:
https://drive.google.com/file/d/1vlQhosnAhCxOwQyWxGnMagXtvAdIv_Gq/view?usp=sharing

You need to use "geometry" node in shader -> Random Per Island socket, but first you need to add seams to determine those islands


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How can I duplicate show/hide conditions of objects while duplicating collection?

As you can see in the above picture, duplicating a collection did not be applied to show/hide condition but rendering condition.
If I duplicate a collection consisting of objects with very complex hierarchy, it's very hard to manage each show/hide conditions one by one.
So I want duplicate a collection including show/hide condions.
How can I do this?

The eye icon hides objects temporarily. To hide objects globally, use the screen icon.
You can enable it from the outliner "funnel" menu.
Temporarily Hide objects (Eye icon)
Resets when a collection is enabled, duplicated or linked to another scene
Globally disable objects (Screen icon  )
Stays on when collection is enabled, duplicated or linked

Your answer is very good but disabling in viewports affects other view layers. I want manage each view layers with different show/hide condition.