text:
Creating floorplans with blender?
Are there any plans to add some basic floor plan features to create architectural plans? Some anotation tools, line styles and maybe a way to render straight on paper format would be amazing.

You are looking for a CAD tool. Try FreeCAD.

Blender is a 3d creation tool. It already has everything you need to make any kind of graphics or architectural visualisations including 3d floor plans like this.
If you wish to work with 2d drawings, Blender can produce lines that can be exported as vector formats including dxf, it is also possible to import vector drawings to Blender and there are many modelling functions in Blender that can be used to work with 2d lines(curves or mesh edges). However it is not designed for this kind of work specifically and for this task you may want to use specially designed software because that might be easier. Special 2d CAD drawing software like ArchiCAD or Revit usually has templates, pre-made libraries of standard symbols, ways to print the drawings or save them to PDF and other useful functionality. It is possible to achieve that in Blender, however it will take a lot longer and will most likely be a lot more work if you only need 2d drawings.
There are some add-ons that aim to provide some functionality related to this. You might want to check Blender-Archipack out and search for more add-ons realated to architecture.
As for plans to make Blender into something that could be used for 2d architectural drawings specifically and would have all the expected functionality of 2d CAD software packages there does not seem to be any at Blender Foundation which is the main organisation developing Blender and it is probably unlikely there will ever be such plans as Blender is designed as specifically 3d creation tool and that is very unlikely to change. It is open source however, so there is nothing stopping anyone to take on such a task and make whatever they want from Blender, however there does not seem to be any serious projects like that at the moment.

Thank you for your answer. I was just wondering this because blender has taken some steps towards 2d by introducing the 2d animation workflow in blender 2.80. But for now I definitely can get away by using CAD software like you mentioned.

I do use Blender to make line drawings and export them to ArchiCAD. I work with interior designers and sometimes it so happens that the visual design of some furniture gets done/modified on my end so it is often easy for me to just make the drawings out of 3d. Bisect operator is very useful: https://imgur.com/KcbmjkL I think it would be easy for me to make other drawings in Blender as well, but I have not tried it, however there are more tools for work with lines in CAD software and there are no convenient ways to print the drawings from Blender.

Some part of you answer is relevant but the rest, which you started defending blender, is absolutely uncessary. Blender is a 3d creation tool and mathematically and algebracilly speaking, 2d is a subspace of the 3d axis space. If blender doesn't offer this, it because of its poor imlementation, not that its focus is not on 2d, 1d or any of what you descirbed. In the end, it is what it is.

Actually, CAD 2d drawings is not the focus of Blender. It's not poor implementation, it's no implementation for most functions related to making CAD 2d drawings. Mathematically speaking 2d is a subset of 3d - you are right. We are not speaking mathematically, when we speak about working with 3d and then working with 2d drawings. There is a very clear distinction between software designed to do CAD and software dedicated to produce graphics. Blender was not designed to do CAD.


text:
How to create a blur (fall-off) in a material using node?
I am trying to make a procedural displacement texture using a gradual fall off.Lets say we have created the following texture:
L
Now I want to give a fall off(or blur the texture) to the give texture like this:

I checked some tutorials and was not able to find a proper ssolution. Most of the tutorial uses a noise texture, for the texture which is working fine, but for displacement it is creating spikes in the object.
I was not able to find a mathematical fuction for bluring a vector image which can be used in blender.
So can someone suggest me a way/or a mathematical fuction to blur(give fall off) a texture using the material nodes.

As far as I know, that's not possible because of how the renderer works : basically, a pixel don't know the state of neighbours pixels when it is rendered, so it can't be blured with them.

Yes i was also thinking the same thing, but i thought that someone on internet might have some suggestion. Thanks.

Are you doing displacement in material nodes, or in modifiers?

source: Stack Exchange

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

sort: votes


text:
Parts of my mesh won't show any image texture when I go to material preview or rendered view
So I'm using blender 2.8 and I'm texturing my mesh in texture paint mode. I've unwrapped it and applied the image to the unwrap. Ive linked the image texture node to the principled bsdf. (did everything right). I painted the whole body, but yet when I go to material preview or rendered view, the arms and legs won't show the texture. There's no lighting issues, but I did notice that in the uv image, when I go to the view tab and press show same material, the arms and legs vertexes are missing vs when I don't have show same material checked. I'm using the same image in texture paint and in my uv image editor tab though, so I'm soooo confused. Someone please help.

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


text:
How to place image texture over procedural texture?
My main target is to put image texture over procedural glass texture. I try to follow youtube tutorial(1 image), i just started, but i faced two problems. First in tutorial BSDF overlay each over, in my case they mix with each over. Second when i connect alpha channel of image texture with Fac of Mix shader my image texture gone black.
Did i missed something or it`s all because of different versions?

To make transparency work in eevee, you must change your material's Blend Mode away from Opaque (In the material properties tab).

I try alpha clip and alpha hashed, this make no difference. With alpha blend model start looking glass-like, but image texture dissapeared at all.

Mix Shader node will output as much % of the 2nd shader as specified by Factor input. Alpha value that you send there says 0 for complete transparency and 1 (100%) for complete opaqueness. So in your setup completely opaque parts of the image are replaced by the shader not using the image - you want to switch the shader inputs so that for 100% opaque parts of the image you display only the image.


text:
How to mirror movement of faces
On both sides of the model i have indentical faces. I want to move them both closer to center. Is there any way to copy my editing but with negative axis. For example i move one face along x axes for 2, then another face also moves for but for x -2.

From the screen as shown, it's a scale?  Switch pivot to 'Median' select both faces, SY + drag, or numerical entry.

Only if you have a mirror modifier applied. You have to cut your model in half then apply the mirror modifier to apply transformations in both sides at the same time

The Mirror modifier does have a bisect feature, so cutting the model in half is optional.


text:
i'm having a trouble changing my liquid base color
so i'm currently adding a base color to my liquid but the color end up changing both of my cup and my liquid (pict 1) i have also made a new materials but it won't change a single color and stayed like this (pict 2), is there any possible way to fix this?

you must make sure that you've assigned one color to an object (or part of the mesh) and the other color to the other one.

sorry but may i ask you to do me a favor doing it step by step?? i'm kinda new to blender haha

select the object, go in Edit mode, select the part of the mesh you want to have a certain color and in the panel on your right choose the right color and click Assign. Go back to Object mode and same thing for the other object.

it works, thank you so much! :)


text:
Is it possible to turn the shader nodes into textures?
I know this is an odd question I make models in blender for my game looking at the procedural nodes it seems way easier to just make the textures using the nodes in blender rather than fixing textures to match my UV's or vice versa. I was hoping there was a way to export them like a texture into ue4 or bake them into the shape of the model at least.

Hello and welcome to Blender.SE :). I believe this thread is what you're looking for.

Thanks! I must of missed that post!


text:
HDRI environment image not showing in final render
So i have a HDRI environment set up but when i render it in cycles i get just a blank white background, and to be honest it doesnt even look like the same lighting?
Using 2.8

Are you sure one of your many hidden objects isn't obscuring the hdri in your final render? when you hide the object with h or in the outliner, it will only be hidden in the viewport, not the render.

Yes that was the problem, thank you :-)


text:
Mesh / unwrapping a face
So i can select desired faces and unwrap. Good.
But if i select a face without holding shift my unwrapped part disapears.
How do i keep the selected faces as the parts i want to use and have that as my mesh?
So for example if i only want to add an image to the selected faces.
So i am trying to save the one on the left.

When assigning an image (material)  to a group of faces it assigns based on which faces are selected on your mesh, not what is selected in the UV Image Editor.

I do not want to assign an image just yet. I want the front of the number plate to be unwrapped. so i dont have to select the faces every time i want to add an image. I want to select the faces and then save the selection?

One useful trick is that you can select faces based on Material, so if you select your numberplate faces and assign a Numberplate material to them, then you can come back in later and from the Material picker just press Select and those faces will be selected again.Not sure if that suits.

That works perfectly thank you so much.


text:
UV Simple question?
Ok sorry very new.
So i have a question to ask.
All i want is to add a custom image to this part of the model.
We sell stickers so in effect i want the model to look like we stuck a sticker on it.
I am kind of struggling to figure out how to do this, i dont need to completely unwrap the selected part just kind of extract that section so that i can put my front number plate design on it.
Is there an easy way to do this, and sorry if it appears dumb.

Does this answer your question? How to add an image texture/color as an overlay to a base texture at a specific part of the object and animate the texture/color alpha?

If you removed all the unnecceray words that do not contribute to the communication like "Ok sorry very new. So i have a question to ask.", "kind of" and "and sorry if it appears dumb." the question would be easier and quicker to read. You should also give it a proper title reflecting your question. It's a question and answer site - everybody already knows it's going to be a question, you definitely do not need to tell us that, just ask it in the title next time and explain it in detail in the body of the question and you will get better answers sooner.

Just trying to be polite. WOW.

That doesnt answer entirely sorry. What i want to do is make a template from the plastic of the bike just of the section that will have the decal applied to it then unwrap only that face section so that i can design onto it and drop it into the model.

Hello :). You can simply select the faces you need and unwrap those. And then assign them a second material with your decal design :).

Hi that sounds like the go. However when i select the faces, they appear when i unwrap them but if i click anywhere else on the screen they all disapear?

Ah yes i have figured that out now and it works like a charm. Thank you so much,

Hey :). Glad to hear you figured it out. You can post a short answer, so others can learn from your solution


text:
Circle in top right hand corner of render
What is this circle in the top right hand corner of the rendered image? i have attached an image of the render i really cant see what it could be.

You mean the dark one? Where you're seeing off the side of your cove?

Yes that one thanks

Make the backdrop larger so that it fills the frame.
Or if you are clipping an existing object, then adjust the clip distance for the camera.
How do I increase the render distance?


text:
All faces change to selected material
Why when i select 1 face and want to change that single face to a specific material does the whole object change to the chosen material.

The first material applies to the whole object - to add a material to a select set of faces, press the plus (+) button on the right of the materials box to add a new material slot. Then, press the other plus (+) button below the box to create a new material for that slot. With the desired faces selected, press Assign.

Thank you that helped :)


text:
White background viewport render image instead of grey
I want to use this material preview by using viewport render image how do i make the background white and not dark grey?

In Material Preview, in the Viewport Shading panel, you can enable Scene World, then in the Properties panel > World, set a World color?

Does this answer your question? Set a white background color for rendering    https://blender.stackexchange.com/questions/222047/viewport-render-image-how-to-render-custom-background-color

In Material Preview, in the Viewport Shading panel, you can enable Scene World:

Then in the Properties panel > World, set a world color:


text:
Transparent material
I have selected a section of tyre and uv unwrapped that section so that i can add a logo.
Saved the logo as png with transparency.
Set to alpha clip and put the node on alpha.
When i render i get a dark patch where it is supposed to be transparent.
What causes that?
And is this the best way to add logos?

You shouldn't try to make a transparent shader here, you don't want light to go through your surface. What you want is to layer you logo on top of the existing color data that are then used into your shader.
Whatever makes your shader's color data, you should mix that with your texture node using a Mix node and using your texture's alpha output as the factor.
For example:

Ok, so to add a logo to a specific area of the tyre. I make a new material in the area i want. Unwrap. Export UV. Add logo. Save as PNG. Use that node set up?

Don't use a new material, you can't stack materials.

Ok, so what is the best way to add a logo to that tyre? i have tried shrink wrapping and that doesnt bring great results either.

Have you tried what I show in my answer? Just use your existing tire's material and mix in your logo with the base color data of that material. Use a different UV map for that texture if you want, but that's about it.

So how do you make a new uv without assigning a material?

You don't need a different material to make a different uv to begin with. Any material uses the active UV of your object, but you can use a UV Map node in your material to manually select any UV map on your object.


text:
Red/green border on object
When I turn the view into "render preview", I get this weird red/green border

Even after opening a new project and loading factory settings I can't get rid of it.
Thanks,

Have you manage to make this happen on a different machine? Do you use default material? Do you render with Cycles or EEVEE?

I don't have any other machine to test it on. Yes everything is default I guess since I only moved the light and changed the mode to render preview. I render with EEVEE

Is your graphics card compatible with blender?

No I know it is not I render on CPU


text:
Fabric goes crazy?
I just tried to reproduce a tutorial to create a procedural fabric fiber and I think I almost got it except that sometimes the fiber doesn't behave as supposed to...

See, the first two rows look good but then only one in too is good...
If someone is nice enough to watch the video and maybe help me find out what's wrong I would really appreciate it !
Thank you in advance.

Hi. I think ideally this question should go to the creator of the tutorial. It's a pretty tough ask to want someone to watch the entire tutorial for you. My suggestion is to watch the tutorial again and try and work out where you went wrong.

Yes you are right, I was just wondering if it may be obvious to anyone


text:
Animation from version 2.79b to 2.80 is not working
I migrated to version 2.8, and the animation of a file is not working. The objects remained present. Since the animation is very long and months of working time, I wold like to recover such animation. Using Blender for artists, which is compatible to version 2.79b, the animation works normally.
The platform is Windows.
If necessary I send the file. Thanks

does this happen with this file only or with every file you try?

very good point. It is not working well with other animations

do you think I am doing something wrong???

how can I upload a file here? Is it possible?

https://blend-exchange.giantcowfilms.com/ is the recommended platform


text:
How to create Sine "Pulse" with math nodes and "From/To" inputs Amplitude?
Based on this answer:Sine wave using only Math nodes?
I have the ability to create an animated waveform with an amplitude from 0 to 1.
Very interesting and useful.
But now I would like to ask the more complex question:
How to change the Minimum and Maximum values of Amplitude with the input values of a group node?
It sounded easy, but math isn't my forte, and I'm getting lost in my problem with it.
For example I would like to set from 0.1 to 0.9 or, do from 2.5 to 100.
I don't know if there is something universal Formula, my idea is that it exists, but I am not able to correctly analyze the formulas present on the internet, as my mathematics is very limited

I don't know any "Sine Pulse". But if you are talking about waveforms, do you mean a Pulse Wave? Would your input values then be the pulse width?

Do I understand it correctly that you want to convert the standard sine wave with an amplitude going from -1 to 1 to something else like going from 0.1 to 0.9 or 2.5 to 100?
Why not simply use a Map Range node after the Sine node? Since we know the output values of the Sine node are From Min = -1 and From Max = 1, just set the other values accordingly to your desired target range, for example To Min = 0.1 and To Max = 0.9 as in the following screenshot:

Of course, if you would want this inside the Group Node, you would maybe again place a Multiply node before the Sine which combines the Speed group input with the driver value and connect the From group input to the To Min input of the Map Range as well as the To group input to the To Max input.
If this isn't what you want you might have to explain a little more what you're aiming for.
For the mathematical background, the group in your screenshot is doing something like the Map Range, just split up in single functions. To make the Map Range conversion of sine from the -1 to 1 range to a different one just with math nodes, you can make the following considerations and computations (forgive me my quite arbitrary variables):
The peak-to-peak-amplitude of the sine function is:
$$sin_{amp}=sin_{max}-sin_{min}= 1-(-1)=1+1=2$$
The peak-to-peak-amplitude of the target range is:
$$t_{amp}=t_{max}-t_{min}= 0.9-0.1=0.8$$
The ratio between those two amplitudes is:
$$R_{t,sin}=\frac{t_{amp}}{sin_{amp}}=0.4$$
The proportional shift from the initial sine minimum to the target minimum (this works if you replace the minima with the maxima as well):
$$S_{t,sin}=t_{min}\cdot\frac{sin_{amp}}{t_{amp}}-sin_{min}=0.1\cdot\frac{2}{0.8}-(-1)=0.25+1=1.25$$
So you get the final formula to map the sine function from [-1, 1] to [0.1, 0.9] if you add the proportional shift to the result of the sine function and multiply it by the amplitude ratio:
$$(sin(x)+S_{t,sin})\cdot R_{t,sin}=(sin(x)+1.25)\cdot0.4$$
And to not have to calculate everything over and over again, this is a node setup for these equations... by the way, if you input any other value instead of a sine function and exchange the s_min and s_max values for any other range, they would resemble the To Min and To Max of the Map Range node and the result of the node tree would work like the Map Range node set to Linear with Clamp disabled.

Hey Gordon this answer is very brilliant and works great. It would also be nice to learn some math, but I think this is what I was looking for with very little effort. You saved me a lot of headaches

@NoobCat Wait a few minutes, I'm working on the maths ;)

@NoobCat I've edited my answer to add some formulas...

This answer satisfies my question 200% you did a lot more than I was asking. I hope it will be useful to many people.

I understood that you want to create a pulse wave.

For this you actually only need a rounding up and down of your values.
Since the node Sinus always gives you float values between $-1$ and $1$, you can round them up or down to exactly $-1$, $0$ or $1$ with the node Round.
The node Map Range will then generate the values you need (either in the range $-1$ - $1$, or $0$ - $1$, depending on the values you have reached before).
Additionally you can influence the pulse width of your square wave.

Based on Gordon's answer, I got what I intended to do. In any case, But this answer is really interesting, a good alternative to what I thought I was doing. A wave like that will be my next goal


text:
Ops with ImportHelper, Possible option to decide whether to open the File Browser window?
When the ImportHelper helper class is inserted into an operator by default, the operator opens a popup with the File Browser window.
Now the question is this, I would like to keep an operator who works in 2 ways, 1 is the one in which a Browser opens for me and the other, is the one that does not open a browser and executes my code.
I'll give an example to explain even better:
class ImportSomeData(Operator, ImportHelper):

    bl_idname = "import.test"
    bl_label = "Import Some Data"

    open_file_browser: BoolProperty(default=True)
    file: StringProperty()

    filter_glob: StringProperty(options={'HIDDEN'}, default='*.jpg;*.jpeg;*.png;*.bmp')

    def execute(self, context):
        if self.open_file_browser:
            # Choose file from File Browser:
            my_file = self.filepath
        else:
            # Choose the file from a known path:
            my_file = self.file

        if os.path.isfile(my_file):
            bpy.data.images.load(my_file)

        return {'FINISHED'}

class LayoutDemoPanel(bpy.types.Panel):
    bl_label = "Layout Demo"
    bl_idname = "SCENE_PT_layout"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "scene"

    def draw(self, context):

        layout = self.layout

        # Button 1:
        # Import file from File Browser:
        ops = layout.operator("import.test", text="Load")
        ops.open_file_browser = True

        # Button 2
        # Import file from a known path:
        ops = layout.operator("import.test", text="Load")
        ops.open_file_browser = True
        ops.file = "c:\\my_file_path\\my_file.jpg"

By the time the code reaches execute it's already too late, the file browser is open. You have to use the invoke method and switch there

As @Gorgious stated, the invoke method is the place to make the switch: open the file browser or not?
But when you call the execute method in the invoke method, the file browser isn't opened automatically, so the extra trick is to bind the file selector within the invoke a second time with context.window_manager.fileselect_add(self) (see Blender docs).
Entire code:
import bpy
from bpy.types import Operator
from bpy.props import BoolProperty, StringProperty
from bpy_extras.io_utils import ImportHelper
import os

class ImportSomeData(Operator, ImportHelper):

    bl_idname = "import.test"
    bl_label = "Import Some Data"

    open_file_browser: BoolProperty(default=True, options={'HIDDEN'})
    file: StringProperty(options={'HIDDEN'})

    filter_glob: StringProperty(options={'HIDDEN'}, default='*.jpg;*.jpeg;*.png;*.bmp')

    # Operator is called, but not executed yet
    def invoke(self, context, event):
        # Choose image file in File browser?
        if self.open_file_browser:
            # Open File browser
            # See: https://docs.blender.org/api/current/bpy.types.WindowManager.html#bpy.types.WindowManager.fileselect_add
            context.window_manager.fileselect_add(self)
            return {'RUNNING_MODAL'}
        else:
            # Do not open File browser, perform operator immediately
            return self.perform_operator()

    # User has selected an image in the File browser
    def execute(self, context):
        self.file = self.filepath
        return self.perform_operator()

    # Perform operator: load image
    def perform_operator(self):
        if os.path.isfile(self.file):
            bpy.data.images.load(self.file)
        return {'FINISHED'}

class LayoutDemoPanel(bpy.types.Panel):
    bl_label = "Layout Demo"
    bl_idname = "SCENE_PT_layout"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "scene"

    def draw(self, context):

        layout = self.layout

        # Button 1:
        # Import file from File Browser:
        ops = layout.operator("import.test", text="Load")
        ops.open_file_browser = True

        # Button 2
        # Import file from a known path:
        ops = layout.operator("import.test", text="Load")
        ops.open_file_browser = False
        ops.file = "c:\\my_file_path\\my_file.jpg"

def register():
    bpy.utils.register_class(LayoutDemoPanel)
    bpy.utils.register_class(ImportSomeData)

def unregister():
    bpy.utils.unregister_class(LayoutDemoPanel)
    bpy.utils.unregister_class(ImportSomeData)

if __name__ == "__main__":
    register()

This is the solution, work fine


text:
Is possible play video in reverse mode into Texture Image node?
I import a Video in the image node of the material, can I set the video in reverse? Is there any trick that can do it? Obviously the blender timeline must always go forward.
I have not found any questions like this on the internet, I have lost a few hours of searching, but I have not found anything about it

In order to get more control about the playback of an Image Sequence or Movie Clip, you can set the Frame property of the Image Texture node to the 'first frame' which allows to set the the 'current frame' based on the Offset property.

If you'd like to reverse the playback of a Movie Clip or Image Sequence, you can add a driver expression to  the Offset property, eg. #3-frame -> last frame - current frame:

For the sake of completeness: You can also loop the playback by using the remainder a.k.a. modulo operator %, eg. #(3-frame) % 3 -> (last frame - current frame) % last frame:

Demo using an Image Sequence (left) and a Movie Clip (right) on the default cube
Note: You can even add a condition to eg. be on the safe side for the 0th frame when cyclic is disabled: #1 if frame==0 else (3-frame) % 3 -> (a if condition else b).

Very very very interesting, I think this is noteworthy. I hope it is as useful to many people as it has been to me

Possibly worth mentioning  too modulus'  partner in crime div a // b can be used for  slow / fast motion.

Floor division? Good idea @batFINGER, I just need to get my test files out of the trash can :D

Brilliant ... What a hack :) Thanks!!! @NoobCat if answer solved your issue consider mark answer as accepted https://blender.stackexchange.com/tour

to do it cyclic you can use this script:
import bpy

# define a driver function
def driver_func(frame, maxframe):

    a = maxframe

    while a - frame < 0:
        a = a + maxframe

    return a - frame

# assign to the driver namespace

bpy.app.driver_namespace["bdriver"] = driver_func

and then use this script as driver:

Run the script once to make it work.
Explanation:
63 is the maxframe (in my case, adapt it to your needs)
The script is pretty "silly", it just gives back maxframe - frame.
Before this it checks whether this subtraction would be positive. if not, it just adds the maxframe again until it is positive.
That's all. Have fun!

The following isn't as nice as using a driver, and it's not very precise but as long as you want the image sequence to start playing backwards from frame 1 of your animation, it kinda works:
Go to frame 1, keyframe the offset to the sequence's length minus one, then go to the frame where the sequence would have finished playing and keyframe the offset to the inverse of that.
For example, with an Image Sequence of 250 images:

Frame 1: Insert key for Offset = 249
Frame 250: Insert key for Offset = -249

To loop it, enable Cyclic, open a Graph Editor tab and add a Cycle Modifier to the Offset curve. Then go one frame past the last key (in my example: 251) and press I to add a key. Without that extra key the loop gets slowly out of sync.
Note: like I said, it's a bit rough, not frame-exact and sometime for some reason you might have to set the second offset to frame length - 2 for it to work. When using that trick in the compositor (second offset to 0) it's a lot more reliable and easier to work with the graph to change the speed.

Consider using a linear generator https://blender.stackexchange.com/questions/134519/f-curve-modifier-animation-whole-values-only

Right, the "imprecision" is because the curve gives float values when frame number are integers? Gonna try to make it work with a generator and update my answer if I do, cheers

Yes that is what I think is happening. Could make a step curve, but if the generator does it probably quicker.


text:
How do I add a list of paths in the Blender preferences manually?
In the Blender preferences I would like to add paths to external resources, but I don't really know how to do it, I am aware that I can register a StringProperty property this way in the preferences:
class MyAddonPreferences(bpy.types.AddonPreferences):

    bl_idname = __name__

    path: bpy.props.StringProperty(name="PATH",subtype='DIR_PATH',description = '')

So I can access the path chosen by the user in this way:
preferences = bpy.context.preferences.addons[__name__].preferences
path = preferences.path

However, this is limiting if the resources can be multiple and chosen by the user. For example I would like to be able to add some other path of your choice with an "Add" or "Remove" button.
Basically I'm trying to memorize some path in the addon preferences.
I have no idea what the best way to do it is

Hello Gorgious, I think you are partly right, the answer of @brockmann is very consistent with my question, while the one you pointed out to me is less consistent with my question, I think brockman's answer will be useful for many people as it is very specifies on this specific question.

Agreed, I proposed the duplicate vote before the answer was posted. Cheers

You would have to declare a CollectionProperty and assign its type to a previously declared PropertyGroup to hold multiple generic entries. Demo based on the code provided in the docs:

bl_info = {
    "name": "Example Add-on Preferences",
    "author": "Your Name Here",
    "version": (1, 0),
    "blender": (2, 80, 0),
    "location": "",
    "description": "Example Add-on",
    "warning": "",
    "doc_url": "",
    "tracker_url": "",
    "category": "Development",
}

import bpy
from bpy.types import Operator, AddonPreferences, PropertyGroup
from bpy.props import StringProperty, CollectionProperty

class CUSTOM_PG_filepaths(PropertyGroup):
    # name: bpy.props.StringProperty()
    path: bpy.props.StringProperty(subtype='FILE_PATH')
    display: bpy.props.BoolProperty()

class ExampleAddonPreferences(AddonPreferences):
    # this must match the add-on name, use '__package__'
    # when defining this in a submodule of a python package.
    bl_idname = __name__

    filepaths: CollectionProperty(
        name="File paths",
        type=CUSTOM_PG_filepaths)

    def draw(self, context):
        layout = self.layout
        layout.label(text="This is a preferences view for our add-on")
        for i in self.filepaths:
            if i.display == True:
                layout.prop(i, "path")

filepath_list = {
    "geo": "//asset.obj",
    "anim": "//asset.fbx",
    "render": "//asset.exr"
}

def register():
    bpy.utils.register_class(CUSTOM_PG_filepaths)
    bpy.utils.register_class(ExampleAddonPreferences)

    paths = bpy.context.preferences.addons[__name__].preferences.filepaths
    if not paths:
        for key, value in filepath_list.items():
            item = paths.add()
            item.name = key
            item.path = value
            item.display = True

def unregister():
    bpy.utils.unregister_class(ExampleAddonPreferences)
    bpy.utils.unregister_class(CUSTOM_PG_filepaths)

If you'd like to allow the user adding an arbitrary amount of filepaths, you can display the contents of the PropertyGroup in a custom UIList which will look like the material list, see:
Create an interface which is similar to the material list box

Alternatively you can just add a simple operator to add a new item:

class OBJECT_OT_addon_prefs_example(Operator):
    """Display example preferences"""
    bl_idname = "object.addon_prefs_example"
    bl_label = "Add-on Preferences Example"
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):
        preferences = context.preferences
        addon_prefs = preferences.addons[__name__].preferences
        item = addon_prefs.filepaths.add()
        item.display = True

        self.report({'INFO'}, "New Filepath added")
        return {'FINISHED'}

Great solution, I had in mind to use CollectionProperty, but I was not sure about it as I thought it would not remain stored, instead, by saving the preferences, all the added paths are saved in the preferences and therefore always available. I would like to give more points for this answer, it really was very helpful and coherent to my question.


text:
Join all faces in a mesh together at once
I imported a model from somewhere and all of the faces on it are separated from each other. It's not noticeable when just using the armature, but I'm trying to do a cloth simulation for part of it so it all just falls apart. Is there a way to join everything together at the edges? If there is, how would I do it? Thanks!

If the vertices are coincident, that would be M  (merge) > By Distance, all selected.

Are the vertices of the neighboring faces at the same location? If that is the case you could try Mesh > Clean up > Merge By Distance.

In Edit Mode select all, Merge by Distance, and keep increasing the merge distance from the default value until all the intersection points merge.


text:
Joining seperate meshes that are parented to bones to single mesh
I have a bunch of seperate meshes that are all part of a character, and are each parented (bone relative parented) to their respective bone (the character is a robot, the meshes are simple shapes that make up the body).  My armature is working well and all, but I'm wanting to add a modifier to the whole character, every mesh.
I figured now that they were all parented I could just Ctrl+J to join them, but when I do, they lose their parenting. I don't want to have to do an armature deform and then have to paint each part hard red/hard blue, unless there is some non-manual way to do it (?).
What's my best option to allow me to add a modifier to the whole character but keep my bones working?  Thank you in advance!

"I don't want to have to do an armature deform and then have to paint each part hard red/hard blue, unless there is some non-manual way to do it (?)."
Yeah so I ended up doing that but found some tricks that made it take barely 5 minutes (for ~20 bones).
Here's a guide for anyone who is in the same situation I was in.

Select all of your meshes and Alt+P to unparent without transform
With all your meshes still selected, join them with Ctrl+J
If you've posed your mesh, select all the bones and Alt+G and Alt+R to reset pose
In object mode, select your conglomerate mesh and the armature and Ctrl+P to parent them, selecting Armature Deform with Automatic Weights
To optimise the repainting process:
a. In Weight Paint mode, set your brush to Draw, and set the Weight and Strength of the brush to 1
b. Next to the brush's Strength slider, there is a dropdown called Brush, in it, disable Front Faces Only
c. Next to the Mode dropdown (where it should currently say Weight Paint), there is an icon of a cube with a highlighted face, hovering over it should say Paint Mask; enable it
Flipping back to Edit Mode, select a face of the loose part of the mesh you wish to paint, and hold down Ctrl+[+] to Select More until the full part is selected
Back in Weight Paint mode, select the corresponding vertex group of the part you selected.  Everything but the corresponding mesh should be wireframe (this means the Paint Mask is working)
Paint all over the part until it is entirely hard red
Hit Ctrl+I to invert selection, turn the weight of your brush down to 0, and paint over everywhere else until it is all hard blue
Rinse and repeat from step 5 with each part, remebering to flip back your brush's Weight to 1 each time

As we say in the industry, bada bing bada boom.
Once you get into a flow of things, you can do your whole model super quick because unless you have a very intricate mesh, there is no precision involved, you can stay in one view the whole time.
Hope that helps anyone else!


text:
Shrinkwrap Modifier - Can't select Vertex Group
I created a vertex group to project an object on via the shrinkwrap modifier. But I can't select any vertex groups in the drop-down.
Any ideas anyone? Thank you very much for taking a look!

You are supposed to create a vertex group on the object which hosts the modifier, not the target object. You currently can't set a target vertex group with the shrinkwrap modifier.
The vertices will be projected against all of the target object's geometry.

Oh, Alright! Got it, thanks for the clarification. Thank you for the explanatory animation, very helpful!


text:
How to set a PointerPropery in an Attributes node?
So I am aware that you can create a custom property directly in Blender, and use it into an Attribute Node,

but in my case, I would like to try to use my pointerproperty as an Attribute, it is written in python and is of type Object. Here is how it is in Python:
from bpy.props import PointerProperty, FloatVectorProperty
from bpy.types import Object, PropertyGroup

class MyClass(PropertyGroup):

    my_vectors: FloatVectorProperty()

bpy.types.Object.my_pointer_prop = PointerProperty(type=MyClass, options={'HIDDEN'},
                                           name="My Pointer")

To access the property, with python you do this:
ob = C.object
ob.my_pointer_prop.my_vectors

Now I would like to set this property in the Attributes node, but I don't know if it is possible, and if so, how to write into it.

Yes, it's possible, use my_pointer_prop.my_vectors
if you change the values via scripting C.object.my_pointer_prop.my_vectors = (1, 0, 1), you need to update the object tag C.object.update_tag()

import bpy
from bpy.props import PointerProperty, FloatVectorProperty
from bpy.types import Object, PropertyGroup

class XX_PG_MyClass(PropertyGroup):

    my_vectors: FloatVectorProperty(default=(1, 0, 0))

class XX_PT_HelloWorldPanel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "Hello World Panel"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_category = "Test"

    def draw(self, context):
        layout = self.layout
        layout.use_property_decorate=False
        layout.use_property_split=True

        prop = context.object.my_pointer_prop

        col = layout.column()
        col.prop(prop, 'my_vectors')

def register():
    bpy.utils.register_class(XX_PG_MyClass)
    bpy.utils.register_class(XX_PT_HelloWorldPanel)
    bpy.types.Object.my_pointer_prop = PointerProperty(type=XX_PG_MyClass)

def unregister():
    del bpy.types.Object.my_pointer_prop
    bpy.utils.unregister_class(XX_PG_MyClass)
    bpy.utils.unregister_class(XX_PT_HelloWorldPanel)

if __name__ == "__main__":
    register()

Ok, perfect, I'm having a problem but I think I solved it. I was assigning values to that property, but they are not updating, unless you do ob.update_tag() they will not change the values in the node. I suggest you add this to the answer, as it will be useful for many.


text:
Way for delete all object inside an Collection "Mycoll" in blender 2.8
I find the bpy.ops, but not find the low level python way to get obj inside a collection and delete . Any idea?

Unlink an object to remove it from a collection.
Py console code, for example sake, creates a new collection that is a copy of "Collection 1".  It contains the default file objects "Cube" "Camera" and "Lamp", and like the original is a child of scene collection.
>>> mycol = D.collections['Collection 1'].copy()
>>> mycol.name
'Collection 1.002'

>>> mycol.objects[:]
[bpy.data.objects['Cube'], bpy.data.objects['Lamp'], bpy.data.objects['Camera']]

To get by name and remove the "Cube" object from collection. (If there is no object named "Cube" in collection get returns None)
>>> cube = mycol.objects.get("Cube")
>>> # remove it from collection
>>> mycol.objects.unlink(cube)
>>> mycol.objects[:]
[bpy.data.objects['Lamp'], bpy.data.objects['Camera']]

Loop thru and empty the whole collection.  Note mycol.objects is boolean False when emtpy.
>>> while mycol.objects:
...     mycol.objects.unlink(mycol.objects[0])
...
>>> mycol.objects[:]
[]

To remove the object ob  from file use bpy.data.objects.remove(ob, do_unlink=True)  Unlinking do_unlink=Trueis the default, and hence can be left out, will unlink from the collection, and all others containing this object, for you.

Nice explanation, in my case I solved with : while mycol.objects:
...     mycol.objects.unlink(mycol.objects[0])


text:
Problem to create background in language other than English in the settings
This is a script part that creates a background, i i run that in Blender with language default (English) run ok , but if i change for example in Spanish
line 3 give error KeyError: 'bpy_prop_collection[key]: key "Background" not found' , because "Background" is translate to "Fondo".
Now i have not intention to translate all name for all languages, exist simple way to change that script to make work in another languages?
1- new_world = bpy.data.worlds.new('My background')
2- new_world.use_nodes = True
3- node = new_world.node_tree.nodes['Background']

Default nodes are in same order
Since you are looking at the default nodes created when setting a world to use nodes, then the zeroth item is the output node, and the first the background node.
Simply reference them on creation, rather than using a key.
>>> nw = bpy.data.worlds.new("xxxx")
>>> nw.use_nodes = True
>>> nw.node_tree.nodes[:]
[bpy.data...nodes["World Output"], bpy.data...nodes["Background"]]

>>> output, bg = nw.node_tree.nodes
>>> output
bpy.data...nodes["World Output"]

>>> bg
bpy.data...nodes["Background"]

To translate
To find what blender translates from the english to the currently set locale,

>>> bpy.app.translations.locale
'es'

>>> nw.node_tree.nodes[:]
[bpy.data...nodes["Entorno"], bpy.data...nodes["Fondo"]]

>>> bpy.app.translations.pgettext("World Output")
'Entorno'

>>> bpy.app.translations.pgettext("Background")
'Fondo'

I think this person doesn't want to translate it one by one every time.

I think you need to read the answer.

Hi @batFINGER i think found the solution node = new_world.node_tree.nodes.get('Background') right?

Huh?  simply node = bg  using that is same as question code only you get node is None instead of a key error. ie if you run output, bg = new_world.node_tree.nodes it doesn't matter what language you are in.  The name set will be bg.name .  I can't be much clearer than this.

I tried this because the blender console from "Background" even when you change language in auto-complete(Shift-Space) , seems to work now, remember to be careful about the ['Background'] method because I see that there are many tutorials with this error

Have try that method with get? i check now in all languages... it seems to work

AFACT node = new_world.node_tree.nodes.get('Background') does not work for all languages.  In spanish it gives me None because it is named "Fondo"  This is going around in circles. If you think that is the answer post it.  Make sure you are creating the new world in each new language, and not keeping a reference to one created in english.

Ok @batFINGER , I'd like to head just because it looks for me works, I don't understand why

@batFINGER, ok i understand why, in my script the world is created ex-novo with an operator that operator clear old World , then create new. he never refers to old worlds. That is my solution

... whereas my solution is to the question.

bat , i have try that method (get)  in blender 2.79 , 2.8 with language different, i not understand but im not with that error

ob = bpy.data.objects.get("I do not exist") throws no error.   It sets ob to None. instead of throwing a key error.  What would be a key-error is now the case if ob is None. If we continue without testing then something like  ob.location throws an error Nonetype has no attribute "location"  In this case the lack of error still has node  referencing nothing if there is no node named "Background".

Right , now i understand , ty


text:
How to check in a "for" cycle if an object is linked (User
I would like to bypass the linked objects in a "for" loop, but I wouldn't know what condition to use.
I'd write something like this:
for o in bpy.context.scene:
    if o is ###"single user":
        print(o.name)

Linked object example:

Do you mean whether an specific object has more than 1 user?

@brockmann, Yes, like to, if object have 1 or more copy linked

Object.data.users returns the number of users

@brockmann ,I think this should be posted as an answer in order to earn points, that's exactly what I was looking for. Ty!

Object.data.users returns the number of data-block users. Proof using the Console:
>>> for ob in bpy.context.scene.objects:
...     print ("Object name:", ob.name, "- Users:", ob.data.users)

Object name: Cube - Users: 1
Object name: Light - Users: 1
Object name: Camera - Users: 1


text:
Problem to update fcurve driver
My problem is get the "angle" for updating the expression inside , in this example the expression is a simple string for explain , but i want controll expression by floatprop(that is not a problem) problem is how to get.
import bpy

def update_the_driver():
    ###this funcition is because driver expression is controlling by some variable
    ob = bpy.context.object

    bend = ob.modifiers.get("bend")
    fcurve = getattr(bend, "angle")####Problem
    driver = fcurve.driver####problem

    driver.expression = "sin(frame/20)"###problem

    return

def make_driver():
    ###this is because i call by a boolean on

    ###some check for presence about modifier name
    #if my_bool is True:
        ob = bpy.context.object
        bend = ob.modifiers.new(name="bend", type='SIMPLE_DEFORM')
        bend.deform_method = 'BEND'

        bend.driver_add("angle")

        update_the_driver()
    #if my_bool is False:

        ###delete diver, and modifier.

    return

make_driver()

#####some controller to call make_driver and update the drivers

To get the driver
Py console code. Look at the drivers collection in the animation data. (animation data can be None need to test)
Default file with cube selected and active. Cube has a deform modifier mod  name "SimpleDeform".  The "angle" property of the modifier has driver.  One component of the cubes location has a driver.
>>> ob = C.object
>>> for fcurve in ob.animation_data.drivers:
...     fcurve.data_path
...
'location'
'modifiers["SimpleDeform"].angle'

Just as we added the driver to the modifier, we can get the path from the ID object (in this case bpy.types.Object type context object)
>>> mod =  C.object.modifiers['SimpleDeform']

>>> mod.id_data
bpy.data.objects['Cube']

>>> mod.id_data is C.object
True

>>> mod.path_from_id("angle")
'modifiers["SimpleDeform"].angle'

This is our "key" to finding driver
>>> key = 'modifiers["SimpleDeform"].angle'
>>> fcurve = C.object.animation_data.drivers.find(key)
>>> fcurve
bpy.data.objects['Cube']...FCurve

>>> fcurve.driver.expression
'var + 0.785'

>>> key = "badkey"
>>> C.object.animation_data.drivers.find(key) is None
True

Here is a helper method, pass an object which returns the angle property driver of a deform modifier named modname or None
def get_deform_angle_driver(ob, modname):
    # does ob have modifiers
    if not hasattr(ob, "modifiers"):
        return None
    # does ob have animation data
    ad = ob.animation_data
    if not ad:
        return None
    # does ob have a modifier of that name
    bend = ob.modifiers.get(modname)
    if not bend:
        return None
    # make the key
    key = bend.path_from_id("angle")
    #key = 'modifiers["%s"].angle' % modname
    fcurve = ad.drivers.find(key)
    # is there a driver fcurve?
    if not fcurve:
        return None
    # woo hoo.. return the drive fcurve
    driver = fcurve.driver

    #driver.expression = "sin(frame/20)"

    return fcurve

# test code
import bpy
ob = bpy.context.object
fcurve = get_deform_angle_driver(ob, "bend")
print(fcurve)

Sorry bat , im confused at this round,  if i use : fcurve = bpy.context.object.animation_data.drivers.find(key)
give me error, is that the way to find custom named modifier? just for not get another modifier with same "Simpledeform"... I'm not very good on the console

key = 'modifiers["%s"].angle' % mod.name So if your modifiermodhas name "bend" the key is'modifiers["bend"].angle'`

fcurve = bpy.context.object.animation_data.drivers.find(key) print(fcurve) ... None... not undertand why the name is exactly

Sorry bat, undertand my problem in the first time i put "modifiers['bend'].angle"  (
quotation marks error) now work !


text:
Make Emission Gradient local
I have this sort of sci-fi scene with ambient emission lights. I would like to have a gradient for each of them. Somehow my setup creates a gradient over the entire image rather than localized for each plane that emits. How would I have to change my setup in the node editor to get both emissions upper and lower to have a gradient in Z?
Thank you very much in advance!
Marlon

Hello :). Just to make sure - both your planes are one object?

Hey, they are one object but different planes that I assigned the material to. Would it help to make them different objects?

When they're one object, you need to use UV mapping. When they're separate, it'll work right away :).

Yep, that worked, as simple as that. I made it separate objects. Thank you!! ;)

When they're one object, you need to use UV mapping. When they're
separate, it'll work right away :). – Jachym Michal 30 mins ago

Making the planes separate objects was the solution (or working with UVs).


text:
Advanced bevel of a rounded corner
I've been racking my brain about this. I've been trying to model this relatively simple handrail but there is one part where I am just stuck. Here is the reference:

Now I sort of tried to bevel the corner of a cuboid. But I only get so far:

I kind of faked the desire result with a cylinder and a sphere, but I am sure there must be a more efficient way of getting there:

Grateful for any input! Thank you in advance!

or you can subdivide (smooth) 3 times a cube, keep only 1/4 and extrude

with a modifier?

or even simpler, bevel several edges

Of course there is a simple way :)

Use Bevel modifier set to Weight, and with  Clamp Overlap
set Bevel Weight to 1 for selected edges.
It will result in some double vertices, you can use the Weld modifier to get rid of them.

Clamp Overlap totally did the trick! Thank you very much!

@JachymMichal  I don't think you did .. I suppose there is one more ... if you want all-quads, make sure the number of segments is even >:).. but that's just cheeky.

@RobinBetts That's a very good one! :)

Just apply the scale of object, then bevel again.
To aply, go to object mode then select your object. Press ctrl + A then select "scale" option.


text:
Making a Toothbrush Bristle in Blender
I am taking the inspiration for this mini-project from a contest on freelancer.com. The goal is to create ONE toothbrush bristle in Blender that behaves (simulates) like a real bristle. No particles or hair simulation allowed. You can find the original instructions link here..
Here is my pitiful result:
https://media.blenderartists.org/uploads/default/original/4X/a/1/1/a1122ab88d1a9541e14df6a5f6ab330cf8dc21c2.mp4
I used a lattice to create a soft body simulation on a cylinder and added weights to the cylinder to simulate some kind of stiffness.

The sphere (tooth) passed straight through the soft body and I can't add any collision modifier to the lattice. I guess I am onto something here, but I feel like I am missing some important steps in my thought process.
How would you go about building something like this? Do you have any ideas? Why is the soft body not colliding with the sphere?
Thank you very much for any input!
Here is the file:
https://blenderartists.org/uploads/short-url/5fYazp97zNu8RXDgYL9wirOqvbh.blend


text:
Spreading micromirrors evenly across surface of a helmet model (Particle effect, procedural, instancing)
I am doing a pre-visualization of an art installation. It looks a bit qwirky ;)
It is to remember the fall of the berlin-wall etc. etc.
So it will be old helmets plated with small mirrors arranged in a very large ball / flower.
BUT the question is, how do i get the tiny mirrors to spread evenly without clipping into each other on the mesh evenly?
I wanted to do that effect for a long time already on a couple of projects.
I thought i could instanciate the micro mirrors onto the surface with a particle emitter and use the normals of the surface etc.
OR alternatively spawn at each vertices a mirror plate. Yet it would be very hard to make them even like a disco ball.
Do you have any ideas? here is a video of the status quo (sorry for the quality) VIDEO of the status quo
The first original helmet looks like this:

i tried your question.
Though i think from the method it is very much like extruding individual faces right? Not entirely sure how it does it ;D to be honest.
here is the result, i believe because of the (rather unclean) mesh topology I can not go that route if I would have to make all faces evenly first.
MAYBE: i could use something like cloth simulation? I could make a "fabric" (just joined mirrors as plane ) and stitch it to the surface? Does anyone has experience with it?

Hi. Does it need to be nearly random like in the video or more regular, like in the picture above?

Hey, rather as closely and tight packed as possible. I wanted it pretty similar like the post beneath by @thibsert.

Is this for images only, or do you need an actually displaced model?

hey, sorry im not entirely sure what you mean ;D (@RobinBetts) I would say actually displaced model. Im trying to re-create the real look of placing tiny mirror plates onto the helmet. EDIT: ah, i think i know what you where referring to. Its just for renders, no animation with the tiles or so. So it can be fixed mesh,

This is a partial shader-only solution, which may be good enough for your visualization.

It depends on a 'Tile UV' node group, available in the download.
'Tile UV' splits a given UV space into square cells,  tile size given by the 'Scale' input.
Its outputs are:

Cell UV, UV coordinates within each cell, -0.5 to 0.5 in X and Y
Dist. Center, the distance of the shading point from  the center of its cell
Dist. Edge, the same for the edges of the cell, here used to put the cracks between the tiles
Min, Mid and Max Tile UVS, which return the locations of the Min. Mid. and Max. X and Y of the shading point's cell in the original, given, UV space.

The steps to applying the shader to your object would be:

UV unwrap the object. The shape/distribution of the tiles will depend on your seams, UV islands and how you straighten / distort them. You could do this while looking at just the Base Color branch of this material, to see how your squares/fragments are coming out. This example just uses the default unwrap of Suzanne, you can see the tiles swell in her mouth region.
Having settled the map, bake an image of the object's  object-space normals for it to use: one way.. with the object at the origin and aligned the world, plug the 'Normal' output of a Geometry node into an emission shader, and bake the 'Emit' from that into a floating-point image, with your UV map active, using Cycles, 1 sample.

You can then use that normal map, as shown in the node tree, to look up the normal at the center of each tile, and use that for the normal of every shading point in the tile.

'Partial', because so far. this is only a Bump/Normal effect. Building the tree to create actual flat-per-tile displacements would be a bit more involved, and need you to bake a position map, too. I don't know how well it would come out - you'd either need very high-res geometry to displace the model, or use Cycles to get the renderer to do it, but If you wanted it, given time, I'd have a look at that.

I'm not gonna pretend I understand what's going on here... but Wow!

@JachymMichal   I'm a bit stuck, I don't know where to go into more detail without making the answer too long

Robin Bestt again!

@lemon Nahhh, we need Rich Sedman to come along and put perfectly flat, beveled, slightly scratched glass on the tiles, randomize their rotations without overlaps, cut triangles out neatly, and throw in some procedural thumbprints for good measure :D

@RobinBetts oh my, THAAANKS! This actually does the trick. I can this way get around the mesh topo. How do you come up with this crafty solution. ;D Super helpful, also on other project i might say. Cool solution.

You can use the Tissue addon.

The addon will tesselate a given shape on a mesh.
Select a tile, shift select your mesh, and use 'tesselate':

From that, if you want to modify the original mesh, you can come back to the tesselation and refresh it.

If the models geometry allows it, you can try that :

In Edit mode, select every face you want a mirror on. In the Face menu, select Exrtude Individual Faces, and move your mouse to give the mirrors some depth. Give them a nice shiny material and you're done.

hey, thanks for the reply, i was originally going for that. But then I would have to re-do the mesh topology entirely for quads. (in 3dsmax poly modeling this would be super fun and easy, in blender i am somehow not at ease like that. ) BUT i wanted to try to see how it will look with the actual mirrors (you can buy them as smal quadratic plates...

hey, i replied to your solution but the response got deleted. Basically it is quite similar to individual face extrusion. Because of my (really shitty) mesh topology this will look horrible ;D. I thought about using something cloth related? Like making a matt of small mirrors and then let blender stitch it onto the surface?


text:
Partially UVW Animated alpha mask for circuit board shader
It want a good old fashioned texture animation, not fade alpha, transparency etc.
I need to animate a circuit board growing effect.
I would take a circuit material, mask it with an alpha map and mask the alpha map with a faded texture that is animated to change UVW position from left to right (so that the animation is from right to left).
I spend a day to figure out why I can not move i.e. a wave texture or a just black image texture with faded border over the alpha mask.
How would you animate a reveal effect like that?

Hey, i progressed a tiny bit. I think it need to combine a black and white gradient with the alpha map. That way i can generate fully transparent alpha map that has the transition to the regular alpha map.  !(https://i.ibb.co/xDrfxJ9/image.png)

Sorry for the format. I still seem to not get the formatting style to embedd images. Here is a quick video illustrating what I want to do and hopefully someone could point in in the right direction. This cost me today almost a full day so far ;(. I could use as fallback just a video of the animation. BUT that would make the full scene into a total adjustment horror. https://youtu.be/6CdpNSf0_TU   @gandalf3 hey I saw that you answered a similar question. Maybe you have an insight into this one? Its greatly appreciated

I found a solution. I wanted to have a mask that I can animate to determine the alpha channels overall opacity, overriding the alpha mask information. (can be used in literally any game vfx...) I have to figure out though how to add this as decal to other materials but that is another one.
Here is the solution:
And here is the solution I used to blend it onto another material. If you can tell me how to make a more clean, proper version of this i would be very grateful. This feels a little bit wacky.

You can now animate the UV coordinates for example or use a image sequence as mask.

Here is a quick animation demonstrating the solution. The question now is rather on how to properly blend it over another base shader that it shows ONLY the growing emission material, not the dark circuits. https://youtu.be/dJcaEmKZH4o


text:
Blender 2.81 and later crashing when adding more lights in Eevee
Anyone experiencing Blender 2.81 and later crashing when adding more lights in EEVEE? More exactly when I add the 4th light to my scene. It works perfectly for 3 lights.
Upon further investigation it's related to if shadows are disabled or not for every added lights. I can add as many lights as I want as long as shadows are disabled, but if more than 3 lights have shadows enabled it crashes or get strange color shading phenomena.
It works using Cycles. My computer specs:

Mac mini 2.3 GHz Intel Core i7
16GB RAM
Intel HD Graphics 4000 1536 MB

Hello! Is Blender crashing or freezing for a very long time? Also, are you in rendered view mode in the viewport? I'm asking because of your computer specs. Double-check that there aren't any typos because 2.3 GHz clock speed for a processor is very, very low.

Hi, as soon as I add the 4th light with shadows enabled it freezes immediately and after around 5 to 10 seconds it crashes with a crash report sent to Apple. It’s 2,3 GHz chock frequency. And I’m in rendered view. I tried to delete everything and just have the lights there and still got same result. However if I start from scratch ( from a new file) and just add the 4 lights I cannot reproduce it

Possibly a GPU error? 2.81 requires a lot of GPU power for certain scenes, and Intel HD is not entirely meant for CGI. Also, I use a 1.68 GHz CPU and I am fine. It is probably not that.

I personally suspect that some of the system resources are being completely exhausted or something, but it's just speculation. It probably is a bug. Try reporting it to the devs at https://developer.blender.org/ , this seems to be more up their alley.

I have similar issues, but with more than 41 lights. The moment I add more lights and turn on the lighting, or if I have less lights than 41 and I try entering VR view and I turn on Lighting it crashes immediately
Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz   2.59 GHz
Installed RAM 32.0 GB
64-bit operating system, x64-based processor
NVIDIA Geforce GTX 1660 Ti


text:
X and Y axis rotation only working as Z axis rotation
When I try rotation x(red) axis rotation or y(green)axis rotation, it always uses z(blue) axis rotation.
i.e. instead of it rotation down it rotates left and right instead. Is this a bug or am I just doing something wrong?

I have never seen a bug like this myself. Does this happen on all blender files or just one? Can you test in a new project? Also, a picture or video of the phenomenon would help.

as person132 says we lack informations, please show some screenshots, perhaps you've simply locked the rotation of the object on its X and Y axis?


text:
Newly added objects dont appear on render
I have started a forest scene with a small log cabin. For a long time everything was normal until today. When I try to add any object to the scene (Be it an instance of an already existing object or something completely new, like a suzanne head) dont appear in my render. They do show up in the viewport in all four modes, but not in the final render. Doesnt have to do anything with the material since there aren't any to begin with. Any idea why this happens and how to fix it? I added two pictures below showing the viewport with the corresponding cycles render.

Most likely the object is added in the active collection that is not enabled for rendering.

Thought about that too, but thats not the case. Its in the same collection as the cabin itself, which is clearly visible in the render

well, can you upload your file here with key parts included? http://blend-exchange.giantcowfilms.com/


text:
Material to bake, what am I doing wrong? Video included
Included Is a video of what I'm doing.
https://www.youtube.com/watch?v=KRAZzMyQUYg

https://blender.meta.stackexchange.com/questions/2449/what-is-the-problem-with-posting-an-image-or-link-and-asking-how-do-i-do-this

do you mind if you can post a .blend file to look at?


text:
Unwrap object to circular UV island
Trying to unwrap my characters chest, and trying to make the UV islands into circles, I had done it once before, but i can't remeber how i actually did it. Here's a screen shot  of what i did:
here's what i got:
TL:DR take a lumpy ciruclar UV map, make it circular. I know it can be done, just not the right addon/hotkeys

One idea that comes to mind is to create shape keys and on one key cast the topology to a sphere, then unwrap on that shape key.

I eventually found the solution on my own!
Here's what happened that wasn't apparent from the errors from the addon: in the moset center area, the geometry look as such:
The fact that the geometry itself wasn't a selectable edge loop was causing the Magic UV addon to fail in unexpected ways. Also, the error codes it was giving were not helpful in the least to trying to triage the problem. The solution was to make sure the UV island was nothing but complete edge loops.

hello, so maybe tell a little bit about what tool in Magic UV you've used?


text:
How do I select individual meshes?
I am creating my first objects following tutorials.
When I try to select the object on the picture, it selects the whole thing and I just want to select the individual cubes to transform them. When I click on it, it selects the whole thing. On the small person, it selects the individual cubes.
When I select the big object it even selects the torch on the hand of the small guy. How do I select individually the different meshes?
I know this is proper beginners question, but it's difficult to find the solution on google.

Thanks!

Switch to edit mode.

You're confusing meshes and object, an object can be made of several different meshes, here several cubes. As Ffeller says, if you select an object and switch to Edit mode, you'll be able to select the different meshes within this object and modify them. You can also extract one of these meshes and make it a different object if you select it and press P, or join the meshes of 2 different objects if you select them and press ctrl J, etc...

Yes, that was it, thank you!!!


text:
By rotating rig, the scale changes
I don't know, if this question was already answered but I have following problem.
I am trying to rotate a wheel at my bike and while changing the bone rotation the wheel changes the scaling, too. But I don't know why. I already applied and cleared all transform, on armature as well on mesh. And I also don't see any changement by scaling or other values, only the rotating value changes. Maybe someone could help me, I would really appreciate that.

Probably the wheel also assigned to the root bone. You have to remove the wheel's verts from the root bone's vertex group.

Thank you very much. I didn't think about that. The problem is solved :) Have a nice day.


text:
Can’t move hierarchy to collection or parent in outliner
I have this one chain hierarchy in my outliner and it doesn’t move to the collection when I parent it to an object in that collection. Even if I try to move it manually it just stays there outside the specific collection in the Scene Collection.

Here I have a collection FISHING BOAT and an empty that serves as a parent for all the parts. When I try to parent the chainlink hierarchy to the empty or move it to the FISHINGBOAT collection, it just stays outside.
What is happening here?
Thank you very much in advance for any ideas or insights!

An object(A) in a certain collection (lets call it Collection 1) can be parented to an object(B) in another collection (lets call it Collection 2), while it(A) remains in Collection 1.
So what you are experiencing is normal/intended behavior.
If you want the child(A) to also be in the same collection as its parent(B), simply select the object(A), press M to move it to another collection, and choose the one the parent is in (Collection 2).

While it's not a direct solution to this, a good workaround is Right-click the main parent object in the Outliner, click "Select Hierarchy" (which selects both the parent and all its children), and then move it to the new Collection.

To move an object with all the nested child objects you can double left click on the triangle icon located before the object's name then the whole tree of objects will be selected and you can move it to another collection by drag and drop.
This workflow also works with a set of parent objects, for example:

If you want to move 2 or more objects with their nested child objects -> double click on the triangle icon of the first object -> while holding ctrl do the same for the rest of them -> drag and drop to a new location
If you want to move a lot of objects placed one after another in the hierarchy with their child objects -> left click on the first and while holding shift double click on the last object's triangle icon -> drag and drop to a new location

If anybody coming across this has the same problem as I did: I hid most of my 11k objects scene using ⇧ Shift + H, then Alt + H didn't work. I found no viable answer online, it probably has something to do with wild parenting/nesting/linking going.
Anyway, this script will unhide all objects in the currently selected collection:
import bpy

# Get the active collection from the currently selected context
context = bpy.context
selected_collection = context.view_layer.active_layer_collection.collection

if selected_collection:
    # Loop through all objects in the active collection
    for obj in selected_collection.objects:
        # Unhide the object
        obj.hide_set(False)
        obj.hide_viewport = False
        obj.hide_render = False
    print(f"All objects in the collection '{selected_collection.name}' have been unhidden.")
else:
    print("No collection is currently selected.")

It seems you're referring to another problem than the question here poses. It's great if you have a solution for a problem, but you can just ask a new question (see [ask]) and answer it yourself. Welcome to Blender.SE!

Oh, posted it in the wrong browser tab in the end it seems. Graceful arrival to the stackexchange scene


text:
Wierd Jagged edges in Viewport Shading mode, how to fix?
When in viewport shading mode, (and any other eevee modes...) I get these annoying, weird jagged edges I've never encountered before. Any idea how to fix it? I'm sure it's a hotkey I pressed without knowing, but it is hard to look at.

Hello :). This looks like z-fighting caused by too large clipping distance https://blender.stackexchange.com/a/1387/

@JachymMichal You are totally right! I my clipping distance was much too small. Set it to 0.01 and it fixed it, thank you Jachym!

Happy to help :). Good luck with your project.


text:
how to disable world light source
I am new in blender. I made a scene whose lightning effect is perfect every object is clearly visible when the world background is removed.
but when I change the world color to white it effects the whole environment and add extra white light which in not needed at all.
I tried a lot to find out solution but failed. please assist if any know the proper  solution weather in evee or in cycle in blender 2.8.
clarifying question again
I want to change the world from black to white but want to disable the white light of the world. thanks

In Cycles click on the World tab and in Ray Visibility only keep Camera enabled. This way the world will be visible but won't light your objects.

In Eevee (also works in Cycles) you need to create a material for your World with an Input > Light Path (Diffuse output) as factor of a Mix Shader:

does'nt work, ambient light is still there

It doesn't work in Eevee, in Eevee you need to create a material for your World with an Input > Light Path as factor


text:
Facial motion capture - animate armatures
I've been doing a little motion capture of my face using the technique outlined in this tutorial https://youtube.com/watch?v=uNK8S19OSmA
It's worked pretty well and the mesh of the face is moving in the viewport as expected.
But when I try to render out a video of this movement the face does not animate and I'm left with footage of an unmoving face.
Am I missing something basic in my understanding of how these armatures are animated?  Do I need to keyframe them individually?  How should I go about this?
Thanks!


text:
Is it possible to obtain dense correspondence field?
I am working on a computer vision algorithm and I have a very simple scene of a rotating sphere, rotating about the z axis. I would like to know 3d point by point correspondences for every frame. I have tried a couple of way to get this but not entirely satisfactory. One is I use the speed pass to obtain 2d flow vectors and then using multiple cameras to obtain 3d flow field which would give me 3d correspondences but i think it's not accurate enough. Is there a more exact way built into blender?

What do you want each pixel in the image to encode?

I am not sure if I want it in image format because I think the flow field representation should be ideal for this if it's just image? The issue is I need to unproject the flow field using depth which will cause ambiguities. I was thinking more like I will sample a set of points of the mesh, and for every point on the mesh there's a function which will give me where they end up at between two consecutive frames. Then by subtracting the points I would get the corresponndences?

Re. Achieving the frame-delay without a second monkey, (which could just be an Empty, of course, all we need are axes) .. https://blender.stackexchange.com/a/40779/35559 is a good answer for getting previous-frame data into a shader. You would need rotations, too..

This answer may have missed the point, but maybe it will help clarify the question:
If you subtract the Object space coordinate of the shading point in the space of object A from the Object space coordinate of the shading point in the space of object B, then the colors on the surface-points of B will represent the World space 3D translation required to take them to the corresponding points on A.

This is OK for rigid objects.. if they're deforming, you could bake the space into an image texture, and look up in UV space instead.

Thanks I will try it out! Instead of having two different objects, how can I do the same for a single object that is animated, and do the same thing between frame 1 and 2?

The only way I can think of atm is to use 2 objects, the animation of one delayed by a frame. It can be hidden in the viewport and/or render without affecting the shader.

I was playing around with python script as well. v = obj.data.vertices[0];co_final = obj.matrix_world * v.co This gives me the correct vertex location after i set the frame number using api. So I can loop through all vertices and obtain 3d points and their differences frame by frame. But the problem is I want the data to be denser than all the vertices. Do you know a way to get sample points on the surface of the object?

I like your method as well. As that means I can just operate in image pixels. If i have 3d points I would have to project them back to camera to have correspondences to pixels not to mention having to handle occlusions.

@Zaw :D  That's why I'm inclined to let the GPU do it with a shader.. It's what the renderer does. However, I believe you can get at the UV parametric interpolation of the mesh through bpy. I'd have to look it up, and there are experts around who would know without having to.. a good question to ask in its own right.


text:
How do i remove distorted vertices inside of my 3D object?
I used mirror to make a character body from skin mesh and applyes some subdivisions
my character look like this now

i tried to use cleand up but no sucess, someone can help me ? how can i make this smooth ?
sorry for my english ppl

you could delete all this part and try a Grid Fill, but are you sure you need so many faces? It doesn't make things easier

Maybe decimating ? i am working with sculpt because of this i have so many faces

there are several ways to simplify a mesh, you can try to reduce the amount of faces by several methods (for example try a simple ctrl E > Un-subdivide), or retopologize, but if you want to do so, it's a completely different question that needs a completely different answer.


text:
Rendering error occures at 60th frame
after rendering animation 60 frames error blurring tiles occurred i started at 80th frame but still same problem. the blurring starts with small boxes when the tiles tries to render at 60th frame and covers everything.

Rendering what? Have you enabled Motion Blur? Can you recreate the issue on a new Blender file. Can you upload a file showing the issue. https://blend-exchange.giantcowfilms.com/

rendering animation using cycles render. motion blur is off.

would need to see at least the output showing the issue (along with what it should render as) but ideally upload to giantcowfilms.You can always cut out anything irrelevant to the issue.


text:
Cutting out logo shape (using Boolean, or knife on a 2D plane) ruins edges when shaded smooth
Hy, sorry if there is simmilar question as mine, I tried to find answer but couldn't.

This is a model of a redbull can and the detail you see is the can opener that has that little bull cutted out.
I tried to cut out the logo from the can opener and just dont know how to do it right so the edges stay smooth when shade smooth is activated.
  First I cutted out the shape using boolean tool, either on a 2d plane(and then solidify it) or on a already 3D shape. No good result.
  Then I have drawn a shape with knife tool in a mesh, same result. Dont know what else to do.
On the first image you can see shade smooth activated.
  On the second, shade flat.
  On third, its in edit mode so you can see the mesh.
Can someone give me a hint how to do job properly? It would mean a lot to me. Im new at blender still.
Thanks a lot!!

Whith Smooth Shading, Did you try to turn on Autosmooth under Object Data Properties panel Normals?

Thats it! Thank you!

After applying smooth you should tick the auto smooth checkbox in the object data panel.
And maybe tinker with the angle if necessary.

Thats it! Thank you, cant believe it was so simple.

I think what you want to do is crease the edge. Select the edges and push shift+E and drag to sharpen up the logo edges. https://youtu.be/lITV4F_P4E0?t=117


text:
Edit Tools Options Visibility Problem
I have gotten into a situation where I cannot seem to get things working correctly. Here is a screen shot of the problem I am having an issue when trying to use tools (like the Extrude tool). I cannot see the options when clicking on the icon for the tool in the edit toolbar.

I tried looking this up in the Help document and I thought that when I read was that switching the mode from Global to Local would solve it but it did not. I am trying to learn how to use Blender and this just started happening so now I am kind of stuck. The only way I can access the options for tools that have them is to use the RMD and then select from the pop up menu. I do not understand what has triggered the icon you see with the + sign.

The screenshot shows that the Extrude Region tool and gizmo from the toolbar were used. The gizmo is the yellow line with the plus icon that indicates in which direction the extrusion is performed when you click and drag on the icon. You can change the type of extrusion by positioning your mouse cursor on the extrude tool in the toolbar and holding the left mouse button. This will open a menu to select the type of extrusion.

The properties of the operator can be modified in the Adjust Last Operation panel. Use the Transformation Orientation to affect the direction of the extrusion. Please note that your options look different in the screenshot because you've executed Dissolve Selection.

Depending on the type of gizmo additional options may be displayed in the header and sidebar for the active tool. For instance the Extrude Region allows you to choose between the Normal and XYZ option.

Axis Type Normal

Axis Type XYZ

Alternatively you can use the E key for extruding without activating the gizmo.

Thanks, I got it all sorted out now. Was just a matter of using the E key and also selecting the correct cursor in some situations. Looks like the gizmo is automatically triggered if you just use the mouse button but it can be changed.

@ntxdave Great. If this answer solved your problem, consider marking it as accepted by clicking on the checkmark next to it.


text:
How to get more control over Freestyle external contour lines
I'm looking for a way to get Freestyle to render just the outline lines around objects.  Using inclusive + logical Or + external contour seems to do what I want when rendering objects over a transparent background. But in the picture below, I'd like for the cube that occludes the plane to still have the external contours of it drawn around all the way around the cube.

Any ideas on how to get those missing freestyle lines rendered?   Thanks!

you have to go into Edit Mode > Select all Edges > Edge > Mark Freestyle Edge
Now you have to go into the "View Layer Properties" and untick everything besides "Edge Mark" under the "Edge Types" Option.
This should do the Trick.


text:
3D Printing Causing Issues
I have only recently started using Blender and have spent free time following the donut tutorial by Blender Guru. I’ve created my first model, a box to hold our remote controls
It all looked ok until I exported it into STL file for Prusaslicer - it looked horrible! Lots of red bits, split layers and a additional false floor.

When I went back into Blender I added 3D Toolbox and get a big list of things that I assume I need to resolve to allow me to print successfully.

With such errors like
- Non Manifold Edge
- Bad Config. Edges
- Intersect Face
- Zero Faces
- Non-Flat Faces
- Thin Faces
- Sharp Edge
- Overhang Face (I suspect these are ok as they are probably lettering etc)
My question is how to resolve the issues?

Please try to find a more specific question title. Thanks

There is a lot, you can check before printing.
-triangulate faces to make them planar. Go to edit mode select all and triangulate
-check if the normals are as they should be, by turn on face orientation in viewport overlays, any red is a bad sign.
-You can turn on a 3D-print addon where is an option to make manifold, also when in edit mode under mesh>clean up there is a few tools that deal with bad geometry.
-ultimately, which iam using when working with a chaotic and more complicated models, there is an awesome voxel remesh. When you set a right voxel size (by try and error) it makes your model clean for print, but in hight mesh density, so I usually use a decimate modifier after that, to make it more "light" to work with.

In your case, it needs some repairing after the boolean. I went to edit mode selected all and triangulated faces. After that I used 3D-Print add-on and clicked make manifold. it did some cleaning. I think it should print completely fine.

Not all warnings are dangerous for print. Like overhangs, it just informs you that there is a place that needs support. Or zero faces - the size that trigger the “degenerate” test to result in that, if you would select all your mesh (in edit mode) scale it and you’ll see the toolbox will not find any “0 faces”. Problem could be intersecting faces or non-manifold.

I found that in 2.80, the make manifold didn’t work and after upgrading to 2.82a, make manifold resolved many of the issues. I tried to export the stl file and import it again into PrusaSlicer, only for it to fail with no error information. I will investigate further to see if I can at least understand it. I still appear to have zero faces and I’m still not sure what all these things are.

@MatthewB you can upload the file and i can take a look at it. If it is a still problematic I would suggest the voxel remesh, that usually sweeps all the problems.

I think I have shared the file (https://www.dropbox.com/s/ek5fgp4ydbah0c2/remote%20box.blend?dl=0). Please let me know if you can view the file

@MatthewB Hi, the model looks OK, just some repairs after the boolean. I went to edit mode selected all and triangulated faces. After that I used 3D-Print add-on and clicked make manifold. it did some cleaning. I think it should print completely fine. I will update my answer.


text:
Sublime Text Code Editor + Blender (How Can I use a External Editor instead of Blender?)
I trying edit the python script archive through Sublime Text Editor instead through Blender Native Editor, because it give not a good support how Sublime Text Editor gives me.
I just want do this, when i edit the code through Sublime Text Editor the Blender detect that has one change in the same archive but not make nothing in script inside of blender editor without i need to click in warning button to refresh the code.
Somebody can give me a solution without need to develop so much code?(I want not be a Blender developer or study very much the Blender)


text:
shape tweening with animation nodes and sound
My ultimate intention is to shape tween different object based on different frequency outputs from a song. IE High notes shape tween objects A, low notes shape tween objects B...and so on. (I am no blender genius) At the moment, I have started with beating hearts.
I managed to get sinusoidal shape tweening using the top 6x nodes seen in the image.
However, relating to the bottom set of nodes, I can't work out how to:
a) extract useful sound values (comparing with online tutorials it seems I can't access some of the sound related nodes)
b) translate them into a useful value to input into shape tween
(I am using blender 2.8RC and a recent animation nodes)

Welcome to StackExchange! Why are you evaluating a constant falloff? You may just plug the Spectrum output to the shape key value.

I am totally not sure what you're asking or indeed if it is relevant to my main question. Since shape Keys operate from 0->1 I wanted to make sure I was putting in values that roughly range from 0->1.


text:
I can't import any mesh
So I'm new to Blender, like only a few days new. And I have no idea why but, when I download any mesh file, and import it, it either says "Invalid Heading" or doesn't appear at all. Again, I have really no idea.. and I feel discouraged.

can you upload an example on a non-importable mesh? is it maybe just really tiny or something? this question is so broad i don't really know where to start..

Not sure, I've tried scaling up and scaling down, yet nothing. Here's the model.. uh thing. https://filebin.net/x4b2nxssdcfzf7yi

i just had to zoom way out (it's big and off to the side). https://imgur.com/rMvjKCB

Make sure that you use File > Import and not File > Open. The latter is for Blender project files only (. blend files).

I still can't find it, like it doesn't exist. I see it in the scene collection though, but like I said, it's nowhere to be found.

Zoom out. its there is just way off to the side; alternatively, you should be able to select it in the collection, hit tab to enter edit mode and either scale it down (eg, s + .1 ) or reset the origin to 0,0,0


text:
Why is the GPU grayed out?
Here is the very elaborate, confusing, even befuddling image which I have selected at the time of this strange error occurring.  https://i.sstatic.net/cNjzD.png

GPU stands for Graphics Processing Unit. It's probably because you don't have an in-built graphics card.

You need to allow Blender to use your graphics card.
Go to Edit->Preferences->System and select the card you want to use.
If there’s nothing there, you don’t have a compatible graphics card.
No worries, CPU rendering works too.

Happy Blendering.


text:
Animation Rendered as Images
I'm new, so this is probably just a silly mistake, but when I rendered my Smoke Animation(as I followed in a tutorial), it just rendered 250 pngs and not a video of animation. Just confused.

You can change the file format in the Output panel to a video container and render straight to animation, but most times if using smoke has a transparent background, you will want to render to frames like this and then bring them into the compositor as an image sequence to combine with other footage, or the VSE.

The answer: https://blender.stackexchange.com/questions/82962/i-only-get-four-video-output-options


text:
New to blender, why is my file so large
first of all I'm new to blender, and I managed to import some SVG files I created of the basic layouts of the models I have.
Its a display video/monitor with its wall mount. Can anyone tell me why the file is large? Also how do I fuse the parts together so it moves as one. Not creating a group, but make it one object for the mount, and one object for the display.
Not sure if you got what I mean,
Any help would be appreciated!

Hi. This question was put on hold because as it stands it is not answerable for lack of essential details to understand the issue. Remember only you have access to your scene, so unless you describe it thoroughly only you know your exact setup, settings and what steps you took to arrive where your are now. Please describe in detail what your issue is, possibly supported by some accompanying screenshots with the [edit] button above. Don't post a comment or ask a new question, editing will automatically put it up for review so it can be reopened.

The .blend files store Blender's internal state which can result in big file sizes when there are plenty geometry, materials, packed textures and/or animations in the project. The more content is in your project, the larger the file.
In your instances it may be large because the imported SVGs use many points to describe paths or Bézier curves. Since Blender converts the SVG into curves in 3D space it also has to store another dimension compared to the 2D SVG.
The second question should be answered by existing answers on Blender's StackExchange:

Parenting objects
Merging


text:
Cloth modifier. Is it possible to set spring rest length and bending angle?
I am working on cloth simulation with blender through python,
Mainly 2 phases,
first, I wrap clothes around a static human body model and apply cloth modifier,
then, I add the cloth modifier again and simulate while the body moves,
the first phase creates certain deformations on the cloth that later affect the results of the simulation,
Is it possible to change the rest length and bending angle of the spring mass model? So that my clothes do not show any kind of bias to certain shapes

So, I have been trying to do this on my own by modifying Blender source code,
in the file 'source/blender/physics/intern/BPH_mass_spring.cpp', in the function 'BPH_cloth_solve', just after it gets the reference to the Cloth object (line 1080), I manually set the rest angle of every spring to 0.0f,
this seems to do the trick w.r.t. bending,
problem now is the rest length,
I'd like to be able to define a vertex group that shall have uniform spring rest length,
I think this could be achieved by adding an additional flag to ClothVertex class (source/blender/blenkernel/BKE_cloth.h, line 96), and changing the ClothModifier so I can add an additional field with a vertex group (and maybe a checkbox to activate this behaviour), then, I think I should set this vertex flag at 'source/blender/blenkernel/intern/cloth.c', function 'cloth_apply_vgroup' (line 650), this should allow me to have access to which springs belong to this vertex group, so in the same part of the code I set rest angle to 0.0f, I can compute an average spring length for those springs and set it as rest length,
nevertheless, I am a little lost on how I can change the Cloth Modifier so that I can include an additional field with a vertex group, so that it later becomes a field of the object ClothModifierData on 'cloth.c',
if anyone has a better picture of how blender source code works and can share thoughts on this I'd be very thankful,
I'll keep trying to figure it out by myself, and if I see reponses from other people that have the same problem, I can share whatever solution I finally come up with


text:
Way to get vertex index to use in new vertex group from selected faces
I try and not undertand if i am on the right way, that code i want to set the select
faces, make a vertex group, this is a piece of code:
    ob = bpy.context.object
    me = ob.data
    bm = bmesh.from_edit_mesh(me)

    vertex = [v for v in bm.verts if (v.select==True and not v.hide)]
    ver_grp = ob.vertex_groups.new(name = "My vertex group")

    ver_grp.add(???,0,'Replace')###not sure if replace can make ex novo

You are on the way
Let's talk about the vertex list line first
You can use v.index for list: vertex = [v.index for v in bm.verts if (v.select==True and not v.hide)], so the vertex will be a list contains your vertices indices.
Next, vertex_group.add() method:
It need 3 arguments (index, weight, type):

index: should be a list contain indices
weight: should be a float value in 0.0~1.0
type: should be a string in {'REPLACE', 'ADD', 'SUBTRACT'}

So you can use ver_grp.add(vertex,1.0,'REPLACE') for it
Sum up your code:
ob = bpy.context.object
me = ob.data
bpy.ops.object.mode_set(mode='EDIT') #You need to enter edit mode for bmesh
bm = bmesh.from_edit_mesh(me)

# not a good practice to use vertex for vertices indices list
v_indices = [v.index for v in bm.verts if (v.select==True and not v.hide)]
ver_grp = ob.vertex_groups.new(name = "My vertex group")

bpy.ops.object.mode_set(mode='OBJECT') #You need to enter object mode for add()
# Add . in float number help people know it is a float instead of int
ver_grp.add(v_indices, 1.0, 'REPLACE') # most of the blender string enums use upper case

Ty , work , in my script  this is performed by a button that appears only in edit mode, is there a way not to exit edit mode for apply ?

@Andrea I don't know, I always set the mode. You can swap back your mode by bpy.ops.object.mode_set(mode='EDIT') or bpy.ops.object.editmode_toggle() in the end of this script. Operator should stay in place while the @poll() still work

Can you explain why you added this comment line please? # not a good practice to use vertex for vertices indices list

@GaryCarlyleCook I was pointing out the original variable name vertex, which is actually a list of vertex.  Should always name for it's plural form to make code less confusing. This is useful when code is long enough and you cannot find the definition of the variable at the first glance. vertex_list or vertices or anything else will better describe the list.

Thanks. Yes, I would agree with that. Otherwise one could get very confused.


text:
Wrapping a 2D image on a 3D sphere
I have a simple code that creates a sphere.
bpy.ops.mesh.primitive_ico_sphere_add(location=(0.0, 0.0, 0.0))

and I would like to add an image of the Sun and 'wrapped' around the sphere made. Is this possible?

Yeah, Unwrap the uv sphere(it's already done but just in case), add the texture of the sun in the image editor(just drag it in), plug colour to an emission shader, mix it with the bsdf as well, increase value at what ever size you like, turn on bloom if you are on eevee.


text:
Blender 4.1 how to disable environmental lighting in the shading viewport
I am using Blender 4.1 and in the Shading Viewport I find it hard to see because of the environmental texture. How can I disable it or set it to white? This only happens in Material Preview mode. It looks find in Render Preview

If you want to deactivate the Material environment effect, open the Viewport Shading panel and enable the World option, now it's the World settings that will be reflected and that will light the object:


text:
How to cut a sphere into two regions based on a 3d curve
I have a 3d curve lying on the unit sphere and I would like to cut the sphere into two "regions" delimited by this 3d curve. My goal is to put the region inside of the curve one color and the other side another color.
However, I'm unable to cut the mesh properly. I tried the knife tool but it's very tedious and I'm looking for something I can just use the curve I have.

Unit sphere? You mean mesh sphere?

Yes, in my case it was the icosphere that I subdivided enough times to approximate a unit sphere

Can you fill the surface "inside" the curve, make it "tick", then use a boolean modifier to remove this "interior" part from the sphere ? By the way, could you share your Blender file using https://blend-exchange.com/ ?

What's the context? Why do you need this? Is this just a modelling step, or do you need it to be possible to animate/update or something like that? What do you need this for?

@MartynasŽiemys I am using Blender for rendering figures for an academic paper. So it only needs to look good for the render, no need to animate.

I think my provided solution should do then. It should be possible to do it with geometry nodes as well, or there might be some more efficient ways to do really a lot of them, like if you have to do several hundreds, it might be worth exploring other solutions, but else than that I would go for simple knife project.

Simple way to do this would be to select the curve, select the sphere, enter edit mode and use Knife Project. You can find it in Mesh menu or using search( F3 ) It's view dependent so the view should be somewhat straight to the surface of the sphere through the curve.