text:
EnumProperty UI 'Dropdown List' Not Displaying in UI element
So I am writing a little add-on for myself (whilst learning UI dev for Blender) and I am attempting to add a DropDown element via an Enum using EnumProperty.
However, after a successful compiling it still does not display in the UI element.
Could anyone please point me in the right direction? Thanks!
import bpy
from bpy.types import PropertyGroup, Scene
from bpy.props import PointerProperty, EnumProperty

# UI Section

class axono_panel:
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = "Axono"
    bl_options = {"DEFAULT_CLOSED"}

class axono_main_panel(axono_panel, bpy.types.Panel):
    bl_idname = "axono_main_panel"
    bl_label = "Axono Rasterisation Settings"

    def draw(self, context):
        layout = self.layout
        scn = bpy.context.scene

        layout.prop(scn, "prop", text='Object')
        layout.label(text="Export Settings")

class axono_second_panel(axono_panel, bpy.types.Panel):
    bl_parent_id = "axono_main_panel"
    bl_label = "Camera Settings"

    projection_items = [
        ("isometric", "Isometric", 0),
        ("dimetric", "Dimetric", 1),
        ("trimetric", "Trimetrix", 2),
    ]

    camera_projection_enum = bpy.props.EnumProperty(
        items=projection_items,
        name="Camera Projection Types",
#        default="isometric",
#        description="Select a typical Axonometric Camera Perspective",
    )

    def draw(self, context):
        layout = self.layout
        layout.label(text="Axonometric Position")

        cp = context.scene

        col = layout.column()
        layout.prop(cp, "camera_projection_enum", text="Projections")

class axono_third_panel(axono_panel, bpy.types.Panel):
    bl_parent_id = "axono_main_panel"
    bl_label = "Resolution Settings"

    def draw(self, context):
        layout = self.layout
        layout.label(text="Render Resolution")

class axono_footer_panel(axono_panel, bpy.types.Panel):
    bl_idname = "axono_footer_panel"
    bl_label = "Axono Rasterisation Render"

    def draw(self, context):
        layout = self.layout
        scn = bpy.context.scene

# Registration Section

classes = (
    axono_main_panel,
    axono_second_panel,
    axono_third_panel,
    axono_footer_panel,
)

def register():
    for cls in classes:
        bpy.utils.register_class(cls)

    Scene.prop = PointerProperty(type=bpy.types.Object)

def unregister():
    for cls in classes:
        bpy.utils.unregister_class(cls)

    del bpy.types.Scene.prop

if __name__ == "__main__":
    register()

You can't serialize data in interface elements like panels or menus, so you have to store it on an object that can serialize it (Property group or an ID type for instance)

That's what I assumed originally. But was receiving 'Could not Register - Error'. Switched it up and the script compiled correctly. Shouldn't have really assumed that would be the fix.

Make a PropertyGroup class and register it to the bpy.types.Scene
import bpy
from bpy.types import Panel, PropertyGroup
from bpy.props import *

class Axono:
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_category = 'Axono'
    bl_options = {'DEFAULT_CLOSED'}

class AXONO_PT_main_panel(Panel, Axono):
    bl_label = 'Axono Rasterisation Settings'

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

        prop = context.scene.custom_prop

        layout.prop(prop, 'object', text='Object')
        layout.label(text='Export Settings')

class AXONO_PT_second_panel(Panel, Axono):
    bl_label = 'Camera Settings'
    bl_parent_id = 'AXONO_PT_main_panel'

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

        prop = context.scene.custom_prop

        layout.label(text='Axonometric Position')

        col = layout.column()
        layout.prop(prop, 'camera_projection', text='Projections')

class AXONO_PT_third_panel(Panel, Axono):
    bl_label = 'Resolution Settings'
    bl_parent_id = 'AXONO_PT_main_panel'

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

        layout.label(text='Render Resolution')

class AXONO_PT_footer_panel(Panel, Axono):
    bl_idname = 'axono_footer_panel'
    bl_label = 'Axono Rasterisation Render'

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

        prop = context.scene.custom_prop

class AXONO_PG_custom_properties(PropertyGroup):

    object : PointerProperty(type=bpy.types.Object)

    camera_projection : EnumProperty(
        name = 'Camera Projection Types',
        description = 'Select a typical Axonometric Camera Perspective',
        items = (
            ('ISOMETRIC', 'Isometric', ''),
            ('DIMETRIC', 'Dimetric', ''),
            ('TRIMETRIC', 'Trimetrix', ''),
        ),
       default = 'ISOMETRIC',
    )

classes = (
    AXONO_PT_main_panel,
    AXONO_PT_second_panel,
    AXONO_PT_third_panel,
    AXONO_PT_footer_panel,
    AXONO_PG_custom_properties,
)

def register():
    for cls in classes:
        bpy.utils.register_class(cls)

    bpy.types.Scene.custom_prop = PointerProperty(type=AXONO_PG_custom_properties)

def unregister():
    for cls in classes:
        bpy.utils.unregister_class(cls)

    del bpy.types.Scene.custom_prop

if __name__ == '__main__':
    register()


text:
Eevee render create contour like appearance
I am still new to Blender and I made this render using Eevee. As you can see the render quality is pretty bad and there are contour like appearance in some places. Also it looks like everything is covered by a fine mist or fog. I used sampling 500 but still the same issue. Any help?

Are you talking about color banding?  Some color banding is unavoidable at low brightnesses (function of the limits of our display tech, and yes, how bad it is depends on each viewer's monitor and how it is set up physically), but you can play with dither in properties/output/post processing.  The "fog" is probably bloom, which you can disable in properties/render; disabling this will probably also fix any apparent banding problems.  Increasing sample count will not help.

Thank you Nathan I didn't know the correct terminology. Thank you for the help.

source: Stack Exchange

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

sort: votes


text:
Why aren't some surfaces in a simple mesh subdividing while others won't?
I've been having some issues subdividing a simple mesh. Normally I expect on subdividing a face the new intersecting lines are made with new polygons, but this isn't always the case. On one face the subdivide command will work but then selecting another face it doesn't work. However, if I select the edge select tool I can see that actually the loop around the face I tried to subdivide is indeed subdivided.

To produce this mesh I simply started with a cube and extruded a surface a few times. The smaller cubes on the far right are extrusions made after subdividing a surface successfully. What am I missing?

Probably, because it is already an ngon (face with >4 verts.)  Center verts or spanning edges will not be created when subdividing an ngon because there is no unambiguous way to create them-- no single way to connect the generated verts.

@Nathan Thanks for that. That's interesting because I thought it was just a rectangle with 4 edges.

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


text:
Baking a Blender modifer to shape keys
I am attempting to export a mesh with a build modifier on it to an gITF animation (to simulate a motion trail). I currently create a curve with the movement data, convert to mesh, and then use the build modifier to animate the motion trail.  Since the animation is modifier based, it does not output to the gITF animation. Is there any way to either bake this modifier to shape keys at each keyframe (either through the GUI or through scripting) or an easier way to animate this that will export in the gITF format? The goal is to export the entire animation to a format that I can display in a webpage (full animated).
I am writing a Python library for dynamic visualization in Blender, so I would prefer any solution to not require any external add-ons, but I will consider them if necessary (only if they are free/open source).
I have attached the blend file: https://drive.google.com/file/d/13A2UVxGV36B66OheCyIsyujuG2zcR4uz/view?usp=sharing

Could you share anim gif of your result? Your blend requires modul installation ...  I'm not experienced with glTF ... but what converts modifiers into anim mesh is Alembic format (.abc) so try that  ...if import .abc can be exported as glTF ... BTW export into shape keys (if possible) would require to animate appearance of shape keys that sounds like tedious work (if not handled by python).

I've exported Alembic fine, but the textures vanish. My fallback idea was to export to Alembic, re-texture and then export, but I wanted to see if there was a less convoluted way. As for the gif, I'll render it out soon and attach a link.


text:
Why exported glTF file, all faces became from quads to triangle
Hi I'm a newbie to blender. I've exported my model from Blender to glTF. When I do export it, I see all faces are made of triangles in wireframe mode. Do you guys know why it converts quads to triangles?

Hi :). glTF format currently does not support quads, only triangles. To keep quads, export to OBJ instead

There's a reason why glTF does this.  See: https://blender.stackexchange.com/a/167383/18161

Tris are the base of any rendering engine and graphics API. Quads are not supported everywhere. So it makes more sense to export in tris, for best support. So glTF format chose this scheme.


text:
Animation Keyframes only appear in "NonLinear Animation" window
Only just starting to learn blender animation so I'm trying to follow some basic tutorials with the FBX I'm using for my game in unity.
I was looking at this:
https://www.youtube.com/watch?v=_C2ClFO3FAY
But when I perform the steps to add a keyframe, neither the dope sheet, nor the timeline populate. The keyframe does get added somewhere though, since my character still moves when scrubbing between frames. Eventually I found them in the "Nonlinear animation" window. So of course I started trying to figure out what that even is which led me down a whole different rabbit hole in which most people don't actually understand what it is either. So I tried to learn more about "NLA" which is... at least related if not the nonlinear animation window itself?
https://www.youtube.com/watch?v=-SQdHehksJw&feature=share
But now I'm even more confused because the keyframes still appear on the dope sheet and everything just fine for this guy. Just not for me.
I'll be honest in that Blender is probably the most complex program I've ever tried to use for animation. Akeytsu, UMotion and Unity itself were far more straightforward. I would love to get this to be at least somewhat closer to the workflow I'm used to.
My steps:
Open new blender file
Import FBX
Open Animation tab
Select 1st frame in dopesheet/timeline/whatever
Rotate bone
click I => create keyframe (want to be more specific but now the I key doesn't bring up any prompt wth!)
Notice no new keyframes in any window except "Nonlinear Animation"
Version: 2.81a

Hi & welcome. Made gif for https://blender.stackexchange.com/a/208471/15543  which I believe shows what to do. Click on action in NLA to select, TAB to edit, (turns green (in my theme)) and puts the action  "in the slot". Once in the slot can add keyframes as expected.

Okay I clicked the action, pressed Tab and it turned green. But keyframes didn't appear in the action editor like in your gif. I see them just above the action in the NLA window but if I try to interact with them at all, it stops "editing" the action and it turns orange again.

please share a (small and simple) file with your problem: https://pasteall.org/blend/

Sure thing: https://pasteall.org/blend/c1305422cbb64969bffc7688df1e6c48

No matter how many times I re-did all the steps the other day, it just would not work at all. Today everything seems fine and I've done absolutely nothing different.
Blender sure is a mystery ¯_(ツ)_/¯

Did you ever find an answer to this? Having the same issue.


text:
How to fix an image texture to object and camera?
I've looked for a similar problem but couldn't find anywhere, so here it goes.
I'm having an issue with fixing the position of this image in the body of the sphere, as you can see, it leaves the position as I pan the view. I need it to be fixed as the object moves and faces the camera at all angles.

Here are the node config I used, I'm absolute beginner on this so take it easy on me.

Thanks everyone who wish to help ;)

Don't use the camera coordinates use UVs. And read: https://blender.stackexchange.com/questions/46424/add-a-transparent-image-on-top-of-a-material

Once you create the texture properly with UVs, then add a track to constraint on the object, so that it rotates with the camera, so that is always facing the lens.

Thanks a lot for the reply, susu. Also the link you sent is very, very helpful! Is there a way to make the texture look flat? Because it gets distorted with the curvature of the sphere, if it doesn't it's ok the way it is.


text:
there is a large circle around my object in blender 2.91
I created an object in blender, and not knowing what i pressed now there is a large circle around my object which i can't seem to select in edit mode or remove (without removing the original base object). Im really new to blender and this is mildly annoying as i cant seem to find an online solution. (others seemed to have switched off proportional editing to solve this but doesn't seem to be the problem here)

Any help would be greatly appreciated!

Go into edit mode with Tab, and you will most likely see that you have a ring of edges there. You can delete it

There is a chance you have chosen face select type in edit mode? Change to vertex of edge select mode to select the ring.

Go to where the proportion editor is where the global and local options are at the top of ur screen and turn it off.

Maybe reconsider this one. ... You can see from the screenshot in the question that Proportional Editing isn't turned on, so this isn't the problem?


text:
How can I make an animated screen for an iPad?
I am trying to make a concept video for the apple pencil. I want to add shots of it drawing on an iPad but I am not sure how to make it. How would I make an iPad screen the shows where the pen drew? Any help or references would be much appreciated.

would Dynamic Paint be an option?

a link to an animation or image how it should look like would improve your question as well....

It might be simpler to do this 'backwards' .. i.e. drive the location of the pen with the end of the stroke it's just 'drawn'.  But, as @Chris says, just show us a sketch of the desired result, so we don't go down the wrong rabbit-hole .. :)


text:
Why does this bone move things it isn't connected to?
I started learning how to rig; however, I ran into this issue where parts of my mesh are moving when I pose a bone they are not connected to. The meshes do not have any constraints, just the bone. I have no clue what is going on. Any help is appreciated.

rigging is pretty complex and since you are a beginner i would highly recommend providing a blend file so we can help you.


text:
How to fix Blender closing itself mid render?
My Blender 3.6 keeps closing itself after rendering approximately 300 frames of my animation.
After some online searching, the only reasoning I could find was not enough vram but I have a 3080ti with 12 gb vram and the rendering at most takes only 4.8gb. Here is a one drive link to the file. Please disregard my horrible lip sync. Its for school and it's just a tutorial for downloading a software I made.
https://1drv.ms/u/s!Ap3ai__CEZG6ja5Qf_VeKSznuLe2Iw?e=3aJWGa

Could you please upload your blend file here: https://blend-exchange.com/

Sorry @LaserLars the file is 305 mb. When I do end up cutting out enough to make it smaller it becomes no different than the original file I downloaded from the blender marketplace. I am using the Rain rig from Blender so I am using their restaurant scene file.

how do you render the animation? (single PNGs or one video file)

@Blunder Sorry about that. Here is a working link: https://1drv.ms/u/s!Ap3ai__CEZG6jcEvcDwVVdgQEovfuA?e=9XEwpq
They are rendered to single pngs using blenders internal Cycles render engine.


text:
How can I create non-planar cross-sections without using CPU-intensive Booleans?
I have a complex scene with many objects and would like to make non-planar cross sections of the entire scene. With simpler scenes I'd use Booleans to cut the geometry, but in this case I don't for the following reasons:

Booleans are CPU intensive
There are hundreds (eventually to be 1000+) of objects in my scene
I want to dynamically change the cross section in the viewport and see the effect with minimal lag.

I found a neat shader node trick that references an empty (called "Cutter Control" in my example) to make shader output to one side of it transparent. All I have to do is add the following custom node group shown below to the shader output of each material that I want included in this effect.

The nice thing about this method is that it is very quick, and I can translate and rotate the empty to slice the scene any way I want, as long as all the materials I'm using have this custom "Cross Section" node. Processing time is near-instant. Below is a side-by-side example with the empty out of the range of influence on the left, and the empty moved about halfway up the z-axis on the right.

And here's a video to show how responsive this method is. This is real-time in the viewport: https://youtu.be/3WLVerEv_rc
The problem is that this method is only limited to making a planar cross section.
My question: Is there a way to create non-planar cross sections without using Booleans using this or a similar method? My imagined solution would be to use a mesh object of any shape to define a volume within which all shaders go transparent.
Credit to this YouTuber for the idea: https://youtu.be/v6YCUGTvcQ0?si=-8lLhYMVcYP6hIuU&t=46

You will have to decide which kind of section you want and use the respective mathematical formula there in the cross section node.

Thanks for that suggestion Daniel. But I was hoping to achieve something more like this, where I could create the cutaway shape I want as a mesh object and have everything within go transparent. I'm not sure there's a way to do that easily with math formulas. https://memory-alpha.fandom.com/wiki/Star_Trek:_The_Motion_Picture?file=Enterprise_NCC-1701-refit_cutaway_poster.jpg

Daniel, thanks again. You put me on the path of finding out more about math nodes and how they can be used to create all kinds of shapes in the shader editor. This is the video that is helping me along: https://youtu.be/oawTbgGtQ5o?si=ntqGAe3OJ_aG8OWx.  With this, I can create a cube volume, wedge volume, etc. Not quite what I was hoping to end up with, but certainly much better than what I started with.


text:
Is there a way to scale uvs based on fabric stretch
I am making a stuffed animal. My goal is to have the grain of the fabric follow a cats hair direction, and to account for the stretch in the fabric. I need the uvs to be proportionate to the model in order to use them for a sewing pattern. I was wondering if there is a way to unwrap uvs to keep them proportionate, while not scattering the islands, so then I can then scale the uvs to match the stretch of the fabric I will be using. I was following seams to sewing pattern, but they don't account for stretch. My other option currently is to rotate and place the islands in Inkscape, which I would prefer not to do. Thanks in advance!
Direction of the grain the fabric will follow, and showing scattering of islands:

What I would like to have (so the pattern is stretched in unison):

https://blender.stackexchange.com/questions/74041/how-to-perfectly-align-uv-coordinates-automatically/ https://blender.stackexchange.com/questions/78358/how-to-straighten-curved-uvs-into-straight-belt/

@DuarteFarrajotaRamos Thanks for answering so quickly. The solutions that you linked don't do what I was hoping for. The 'unwrap' option works fine for proportions, but I was hoping that there was a way to have the islands close to their original position on the model. Is there a way for the islands to be less scattered in their placement in the uv map?


text:
Blender doesn't display texture properly but meshlab does
I have an obj along with a texture file but the texture is not loading properly on blender.

But when I load the same obj into meshlab it loads it perfectly

Here's the obj link: https://drive.google.com/file/d/1FfU37yN3ei2llcKSAKS2mwQBtWpVFPtX/view?usp=sharing
and texture link: https://drive.google.com/file/d/1gW6NOAwOS-qXw97ar7iOrMlClOK-Kyds/view?usp=sharing

Blender results in that state, because there is not UVmap delivered with obj.
On other hand, importing your OBJ to Meshlab doesn't use your texture at all. I would say it uses Vertex Color info ... the weird thing is imported OBJ to Blender doesn't have any Vertex Color either, even when I export obj from meshlab with vertex color ... hm.

Before than someone smarter will answer this "mystery" ... You have two options - open your OBJ file in Meshlab and Export as PLY format. There I have no issue to use the Vertex Color.

If you want to use Image Texture, you would have to create UV map in Meshlab first and than transfer Vertex Color to Texture. For more info see https://stackoverflow.com/a/51582851/10148444 ... this worked for me too.


text:
Combine blender files
I have two different blender files on different devices I wanna combine with each other. Unfortunately I can‘t keep my material on the imported file and the animations don’t work anymore once I import them.
How do I solve this problem?
I tried to save the file I want to import as a fpx and export it and import it afterwards but some parts are missing the material I created in blender and the others are pink on the outsides (the objects I added material threw a picture). The animations don’t move and just stay the way they were when I exported them.

Use File -> Append and browse to the other blend file instead

You should be able to append one file's content into another one.
To do that, head over to the File → Append menu. Navigate to the .blend you want to merge in, and open it.
From there, you can do things in several ways. If you want to just import all your 3D objects and their dependencies, go to the Objects folder, and select everything, then click Append.
However, you might be interested in keeping things somewhat separated, in which case you probably append the scene inside the Scene folder.


text:
Color changes drastically after eevee render
this might be a beginner question but i can't seem to understand why my colour ends up differently after rendering the image on eevee. Here is the viewport display of my setup:

image 1: Red background
From this view, I hit f12 to render the image from camera using eevee:

image 2: Blue background
As we can see, the viewport shows a Red background while the render shows a Blue background. I'm still quite new to blender and this might be due to a rookie mistake, but it's confusing the hell out of me and i'll appreciate the help :)

Here's a reference to viewport background: https://blender.stackexchange.com/questions/164502/how-to-change-the-viewport-background-color ... not seeing a background in eevee but there is probably a setting (Scene Properties: Background Scene?). The viewport seems like it is rendered with Eevee, but you are seeing one difference.

In the second image you posted, there seems to be evidence of Z-fighting in the top left. Is there a chance you made a blue "display background" in the same place as the red one, but hid it in the viewport? Hidden objects will still be visible in renders. It looks like it's trying to display 2 backgrounds at the same time. Z-fighting is another way of saying "blender doesn't know which one's supposed to be in front".

@ChristopherBennett Yes thank you, this did the trick. I made multiple scenes and duplicated the background, which i turned off in viewport display but not in render which corresponded to the phenomenon you brought up.


text:
how to display f-curves that are not showing
When i insert a keyframe to the emission strength of material "light_red" in image 1(yellow in the bottom right), a keyframe is added to the graph editor
image 1:

However when i add a keyframe to material "light_blue" in image 2, no keyframes are added. Furthermore, i cannot even see the graph of all the keyframes even after selecting the object. This is perplexing for me, as the object still goes through the colour change as I had input but i am unable to see the graph editor.
image 2:

How do i get blender to display the missing curves in image 2 so that I can start adjusting the shape of it?

Try to press A - Select All and than press Home key to View Selected. If it doesn't help please share your blend just with your two lights. Thank you


text:
How to deconstruct a ready-made model to view the inside?
okay, so i recently bought the transportation addon from here https://blendermarket.com/products/transportation and i realised it was intricately built.. to the point that the seats, entertainment system etc and even the engine was modelled:

Here is an image of how dense the mesh is:

The problem is, there is no ready made "door" or "hood" and the whole frame is one solid mesh.
My question is: what is the best workflow to "deconstruct" a dense model like shown so that i can make the doors and hood able to swing open and shut to see the intricacies inside? Or what is the least tedious method to split the door/hood from the rest of the metal frame?

you can select the faces and Y to seperate as a different mesh, or P to separate as a different object, or select an edge and V to rip

There is no way around splitting it up manually. Select one vert, hit L to get the connected components, hit P > Seperate by selection. OR seperate by material in the first place. https://blender.stackexchange.com/questions/6184/splitting-pieces-of-a-mesh-into-a-new-object

Are you sure the whole mesh has no loose parts? In Edit mode, hover the mouse over the door and press L to selected linked verts. If it only selects the door then it's a loose part and you can separate or animate it. I would be surprised one modeled the interior and engine and you cannot see it.


text:
How to display measurement lengths in Blender 2.9?
I want to get this result in Blender 2.9:

However for all the tutorials i searched online, all i could find were how to achieve this in Blender 2.8 as shown:

I assumed it would be under the gizmo panel in 2.9, but i can't seem to find the checkbox for it. All i get is this:

Where is the option to show measurements in Blender 2.9?

Hello :). It's still there, but you need to be in edit mode.

Yes this worked THANK YOU. Wow I feel so stupid right now, these features are really good at playing hide-and-seek...


text:
obvious seam artifact in mirror modifier with subsurf modifier
Okay i understand this is a common problem, and the common solution is setting the subsurf after the mirror in the modifier stack as shown here: Subsurf and mirror modifier creating a split in mesh
However in my case, my subsurf is already applied after the mirror and i still have an obvious seam. Here is the problem and how i tried to rectify it(in vain):

How do i get rid of this artifact?

Check your Normals (Face Orientation) https://blender.stackexchange.com/a/169407/2214 or try increase Merge value in Mirror

Also make sure you don't have an internal face at the join.


text:
Workflow to UV unwrap the exterior of a real world product with slight defects, given a lack of resources
Ok sorry for the weird title but bear with me on this one! I want to model this bottle from scratch for use in a product animation:

which I don't have foresee a problem in the modelling within blender.
However, the problem arises because the exterior sticker of the bottle that I have is slightly worn out. Also, I don't have the original sticker image as a jpg file to simply UV unwrap onto my mesh. I'm also not the most proficient in third party apps used for image editing.
So here's the question:
What is the best workflow for me to model a perfect version of this bottle in blender without any imperfections, given my current (lack of) resources? Correct me if I'm wrong, but this is my current thought process to model the outer sticker:

carefully peel the sticker and take an image of it on a flat surface
use a third party app(photoshop?) to remove and repair the imperfections
uv unwrap the edited image onto the mesh in blender.

Assuming we use photoshop, can someone explain the relevant tools I need to use within the program? I'll be glad to work from a general idea so at least I know what areas in photoshop to look into for this particular case!

Hi :) It would probably be easiest to model the sticker from scratch. The font is Helvetica Black and Regular and the logo is easily found on google. Either way, not really related to Blender.

Btw, you could make the sticker by simply bending a plane. No UV unwrapping needed ;)


text:
Why can't i select objects using the outliner tab?
Pressing "select objects" from the drop-down menu after right clicking on it doesn't select the objects in the 3d viewport. I'm confused because this was working yesterday and now it doesn't.

Can someone shed some light on this issue? Thanks!

You are viewing the Outliner in Scenes mode

You need to change it to View Layer mode

Seems like it should work in both modes, but it doesn't.


text:
how to stick an object to another object that has a wave modifier?
I want to get the black strip to follow the wave motion of the white plane above it

i tried simply linking the modifiers of the black strip to the plane, but this was the result:

Here is the modifiers i am using on the plane:

Any solutions to this?

Does the black plane have enough geometry to deform along the waves ?

yup, tried with many subdivisions and the same "thickening" effect occurs

From your second screen it seems like wrong order of modifiers ... Solidify-Wave-Subdiv ... the order on the third one is correct (Subdiv-Wave-Solidify).
Are you sure both objects use this order?

Few Loop Cuts Ctrl+R

Same modifiers

Another way ... use the Wave modifier only for Plane and for Strip object add Surface Deform modifier with Plane as target. Be sure before Bind disable Wave modifier and enable back after binding.


text:
How to render a video based on "material preview" viewport shading
I am trying to make a technical animation and i want to render a video based on the "material preview" shader type which looks like this:

I do not want a rendered view for my video, I tried adding a sun lamp and it looks really bad:

Is there a way to render a video based on material preview(top example) instead of rendered view? Thanks!

https://docs.blender.org/manual/en/latest/editors/3dview/viewport_render.html
You can render your material preview viewport by following this guide.

Use Workbench render engine.

You can render animation from viewport, by choosing View -> Viewport Render Animation
[
You may want to disable overlays (icon is located in top right by default), or disable specific parts of it in the drop-down menu.


text:
Why is base colour wheel only giving me black as an option
I don't know when this happened but my base colour wheel doesn't want to cooperate to give me the colours that i want. The problem:

How do i get the colour wheel to show all the colours again and what did i do to make this happen? Thanks!
ps: Not sure if this is related but the animation i have for the + signs are changing alpha value from 0 to 1, using alpha blend as shown:

You have set the luminosity to a low level. Bring it up.

The circle is to set hue and saturation. The strip to the right is to set luminosity.
Alternatively use the sliders for the different color channels.

Or use the Mouse Wheel to adjust luminosity.
To reset the color wheel to default press the ⟵ Backspace


text:
How to control rotation explicitly such that it only rotates parallel to a plane
So i have a problem as shown:

I want the arrow to rotate about the origin, but still remain parallel to the cylinder. However, the interpolation messes up and the arrow clips into the cylinder instead.
How do i ensure that the arrow only rotates on the same plane as the cylinder?
Is there a way to make an object rotate about any arbitrary axis (instead of a point origin) specified?

maybe this will answer? https://blender.stackexchange.com/questions/129834/how-do-i-rotate-an-object-along-its-own-axis-windmill

There are many ways to do it.
One of them: enable the "Copy attributes" addon in the preferences menu.
Set the 3D cursor in the spot you want as pivot point.
Create an empty in the 3d cursor loc.
Select the empty, shift select the cylinder, press Ctrl C "Copy Rot".
Set the arrow child of the empty.
Animate the empty (in my example on its Z local axis).


text:
How do i remove objects within another object's collection?
I have no idea how to phrase this properly, so I hope a gif will be able to show. This is a more a matter of scene collection organization rather than modelling, but its driving me nuts.

As shown, i'm trying to remove the objects within the "connector" object collection into the "Scene" collection but it just goes back into the connector object again.
My questions are:

Why is the "connector" object a collection in the first place?
Why are the 4 objects highlighted stuck within the "connector" object collection? (I'm not sure what i did to get them stuck there)
How do i go about removing these 4 objects from the "connector" collection into another collection, like the other objects?

The 'connector' object is not actually a collection. Most probably, the other four objects are parented to the connector object, thus causing them to be shown under this object in the Outliner.
In response to your second question, the objects are actually getting moved to the Scene Collection, but they remain where they are greyed out simply to display the hierarchy (as they are still parented to the 'connector' object). Scrolling down to the bottom of the Outliner should find the four objects in the Scene  Collection.
An alternative way to move these objects is to press M.


text:
Intersect boolean in animation doesn't render properly and gives blackout/whiteout
I'm creating an animation where a plane moves leftwards with a boolean intersect modifier, whereby only the intersect will show as shown in image 1.

image 1: frame 75, perfectly normal
However, this is not the case through the animation. What happens at (what i presume to be) random keyframes is a black or white boolean cube. This anomaly shows up in my video renders as well, as shown here:

image 2: frame 95, blackout

image 3: frame 128, whiteout
my question is, what the hell is going on and how do i fix it

Hello, there is an option in the boolean modifier, try toggling between "Exact" and "Fast" and see if it changes anything. Also, boolean does not work well with non-manifold meshes (eg a plane) Try adding a solidify modifier with a very low value

@Gorgious Thanks for the help, changing the value from "Exact" to "Fast" seemed to do it. Not only did it solve my problem, it also increased the frame rate drastically. Could you instead type this as an answer so i can mark it as solution to close this thread? Cheers

In a recent version an "Exact" mode has been added to the boolean modifier. It is enabled by default, and it is supposed to handle non-manifold and co-planar meshes better than the regular "Fast", mode, but it is also computationally very heavy and there are still edge cases where it fails.
You can try to toggle between "Exact" and "Fast" and see if it changes anything.
Also, booleans do not work well with non-manifold meshes (eg a plane) You can try adding a solidify modifier with a very low value.


text:
How would I connect these parts in a non destructive way?

I want to connect those rounded edges to the ngon next to them in a non-destructive way. This is my low poly model, and I want to connect them so that I can subdivide this model heavily and sculpt on it. The image below is what I tried to do by simply adding loopcuts to connect them.

The only problem is that when I subdivide it, it creates horrible topology that is very difficult to work with:

So does anyone know how I would connect these to obtain good topology when subdividing?

Welcome.
You can add the green cuts in the below picture to support your geometry better along the horizontal axis. That would maintain a nicer grid pattern in subdivision. You may also choose to delete the cuts marked in red if you want to maintain all quads, though triangles might not even cause much of a problem in this case.

Note though that for sculpting this most likely doesn't really matter either way. In sculpting you will deform your high density mesh in all kinds of weird ways and in most cases you'll have to do a retopology pass in the end anyways if you want nice elegant and/or performant geometry. This might not be true for your particular usecase, but usually that is how it works.


text:
Lines in Noise texture
I am trying to add a noise texture to my letters to make them have a partially emissive texture that I can then move throughout the animation over the letters. However the noise texture is barely visible, and if I scale it up it does not show up with dots as usual but rather in irregular lines. I added a box and there it worked normally, and I have tried to rescale the uv maps. I already set the location and oration of the letters throughout the animation, does that have smith to do with it?
Here is what it looks like with noise texture on the box versus text, and the second one scaled up to be visible.

please show us your uv or provide blend file. thx

In your first screenshot, you have connected the 3-dimensional Vector Mapping output to the 1-dimensional Scale input. This, combined with the non-uniform scaling parameters in the Vector Mapping, possibly leads to the weird lines.
Also, you are not using the UVs from your Texture Coordinate Node...

@LaserLars that deserves a full post below. Care to flesh it out into a formal answer?


text:
How do you make a sky texture ignore shadows?
I'm modeling an indoor scene where I need a skybox that lights up all of the objects even though it is indoors. Is there a way specifically to get a skybox texture in cycles that just lights up everything indiscriminately even if it would be in the shadow of something else? Thanks.

Does this answer your question? adding an hdri in blender 2.9?

Unfortunately in Cycles,, doing something like that would probably require you to render one layer with the "outer structure" removed, then another with just the outer structure, then composite them together. However, what many see as a deficit in EEVEE, is that is does just what you are looking for - HDRI's light objects regardless of whether or not their "view" of the HDRI is blocked (this includes "interior" areas) - perhaps you could use this to your advantage.

Do you mind explaining why you want to use a skybox texture specifically?
They are most useful for either recreating on-site lighting (eg for VFX), in which case you don't need the walls modeled, or for reflections, where it would be odd to not include the wall.
Is there a reason for cycles not EEVEE? Generally you use cycles because you want more realistic light behavior.
Note: You do not necessarily need render passes - you can try unchecking the "shadows" option in the "ray visibility" section of the object properties for the walls.


text:
Are there any wildcards to exclude by name in the search field?
For example, I have Leg.R and Leg.CTRL.R bones. I want to set such a search so that it removes the word "CTRL". But the invert button won't help here because I want it to be in common search bar.
For example, I want to find only the hands or fingers of the right hand, but without the word "CTRL", and the invert button will not help here.

what object type do you want to search by name? Could you up load a image to let us more easy to understand

@XY The example he gives in the question says it's bones. I think it's quite easy to understand. Let's say his model has an armature with lots of bones. The ones on the right have a suffix '.R' and the ones on the left have '.L' and some seem to be controller bones which also have a secondary suffix '.CTRL' before the '.R' and '.L'. Now if the right hand has bone names like 'hand.finger1.R', 'hand.finger1.CTRL.R' 'hand.finger2.R', 'hand.finger2.CTRL.R' etc. he wants to filter for something like 'finger*.R', but he doesn't want those bones which have a '.CTRL' inbetween.

Gordon Brinkmann, yes, that's exactly what I mean! Thank you.

Blender has a batch rename function that takes wildcard format called regular expressions. Regular expressions can be very flexible and have form that says must have this part but not that. you just have to find the right wildcard for your search.

That's the thing, it doesn't exist. I tested different characters before posting this question. I know for sure that ?, * and [] work.
For example, in the link you gave, they write:
"[^b]at matches all strings matched by .at except "bat"."
Ok. But it doesn't work in Blender.

Can the built-in Batch Rename feature grab let's say Object Name and use that as a prefix for Object Data such as Mesh Name?

Do you want to select them or rename them?
1) Make sure you are in Object mode and select the armature object.
2) Go to Text Editor paste the text:
import bpy

oj = bpy.context.object
bones = oj.data.bones

for bo in bones:
    bo.select = True  if bo.name.find("CTRL") == -1 else False

3) Run the script, the bone will select if name not include "CTRL"


text:
nothing is affecting viewport
I opened my donut project that I had been working on, and all of my materials and properties had been gone and were not showing up on my donut in viewport, except they were all still in the properties window like I had left them, they just were not affecting the donut for some reason. It also said I was rendering in cycles, when clearly i was rendering in evee as you can see in the photo. So it seems that nothing I do that isnt directly in the viewport(like scaling, rotating, moving the donut or moving the camera) isnt affecting the model, but all the data from the properties and materials is still there. HELP!

maybe you should watch some basic tutorials about blender like here https://www.blender.org/support/tutorials/. they are free and really good for beginners.

did you try out to press one of these buttons?

They change the way objects will be shown in the viewport.

YES! Thank you Chris, I am forever in your debt!

no problem. Glad i could help. Please press the checkmark left to my answer. Thank you.


text:
Applying the knife cut tool
is there a way to apply the cut used by the knife tool with another button rather than hitting the Enter key? can I change that? thank you in advance :D

You can change keys assigned to certain functions in keymap, knife:

Just go to Edit > Preferences > Keymap > Search for knife and find Confirm command

Thank you Miko much appreciation <3


text:
How to pause a video animation in video editor
I am trying to create a technical animation where i require a video to pause at specific intervals to include explanation texts. For example, in the image below i require a cut to be done exactly where the blue line is:

I am aware using keyboard shortcut "K" allows for me to split strips where i can split the video, followed by splitting the image apart from the video as such:

However, when i scrub to the portions where the portion is black no video will be playing.
Tl;dr: How do i easily pause an animation such that i can add other edits in the other channels while keeping a still frame in the original video.
(the only brute force method i can think of currently is duplicating that still frame that i cut [2nd image] for the whole duration of the blank space.)

You would have to split the strip using Shift+K, then ...
just grab the right end of the left strip with your cursor and move it to the right. Then the last pic will be shown as long as you dragged the right edge.

thanks for the reply, but this doesn't work. When i do that, it continues the clip from where I stopped instead of holding the last frame.

you are right, sorry, i updated my answer


text:
.OBJ lacking "apply unit" scale option
I'm working on models that are much smaller than the default cube, which seems to lead to a number of issues (auto-merge kicking in too liberally, color ramp coverage being squished towards the center, etc)
I would think that I could fix this by changing the unit scale, so that the smaller models I'm working on would be treated the same as objects around the default cube size (because they would actually be that size in the file).
The problem is, .OBJ files don't seem to have the same export options as .FBX and .STL files - there's no "apply unit" (FBX) or "scene unit" (STL) option, only a generic scaling option, which I would prefer to keep as whichever number I need it to be to convert between Blender's scale and a game engine's scale.
Am I misunderstanding how I should approach this, or is there some sort of workaround for applying the scene's unit scale for .OBJ exports?


text:
Applying an armature modifier causes the clothing item to stick the sleeves up, how can I correct
I modeled a shirt while in pose mode (a T pose) the armature rest pose was an A pose. I have changed the rest mode to the T pose and the shirt fits. I can transfer weights and it looks good, like this:
But after I apply the armature modifier, the sleeves inexplicably stick up in the air, like this:

The shirt is parented to the armature and I have run out of ideas for how to correct this. Any suggestions would be appreciated.

Share your file. https://blend-exchange.com

Looks like your cloth has a 2. Armature modifier on it.


text:
How do I enlarge outliner font?
Please let me know how to enlarge outliner font, Icon display. + and - bottom does NOT work on outliner.

You can change your UI font size, and then use Numpad - where you want smaller font.
Preferences > Themes> Text Style > Widget


text:
Hollow a design to 3D Print
Does anyone know how to make an object hollow in order to cut cost for 3D prints? I want to create and upload to shapeways.com to make metal jewelry. Thank you in advance.

Have you tried the solidify modifier?
https://docs.blender.org/manual/en/2.91/modeling/modifiers/generate/solidify.html?highlight=solidify

Can you update your question with a picture of your model. Different models require different approaches due to complexity.

@Psyonic I even tried hollowing the standard Blender cube using Solidify but it still uploads to shapewayys as solid. My apologies, I'm new to forums and I don't see how to upload a picture.

I've not used Shapeways but the object probably needs a hole in it to be considered "hollow" If it just a shell then resin printing will not be able to drain the resin out so they might truncate any internal structures.
You can add pictures to your post with the bar above where you write the text, the little symbol that looks like a mountain with a sun

It depends on the software you are using to convert your mesh to stl, usually if your mesh is manifold you will be able to tweak the settings to make it hollow


text:
The meta ball isn't working in geometry nodes
I don't know why this is happening, it should work but it doesn't. Can someone please explain why?

Hello ! The Metaball type is not (yet) supported in geometry nodes, it is automatically converted to a regular mesh when it goes out of the Object Info node.

@Gorgious thank you. also if you know of a way to do something like this than please tell.

You can use a particle system


text:
Adding points to existing hair curves?
is there a way to add vertices to the new hair curves after they've been created either in sculpt mode or with geo nodes? I know you can delete vertices, but I can't seem to figure out how to subdivide/add them in, and it's so hard to find information on hair curves. Thanks! :)

New control points can be added using the Resample Curve node in geometry nodes. The node has 3 modes. Count, length and evaluated.
Count is the number of points that you will have after resampling. It's an integer field. Larger the value, more the points.
Length is the distance between two points. Lower the distance, more the points.
Evaluated uses a Boolean field to evaluate.
But in order to actually modify these new points you will have to apply the geometry nodes modifier.

Aha, thank you! I've been pretty much bound to the essentials assets because I'm scared of geometry nodes lol, guess I should put some time into learning them. I also just figured out a hacky way to subdivide the curves with the assets from 3.5: add in a curl modifier, turn off existing guide map and turn down guide distance and radius to 0, then set desired subdiv level. Apply that, and it'll subdivide the curves without changing them, then you can add the smooth curves asset if you want.


text:
Apply Transformation from Mapping Node to UVs?
I'm using the mapping node in the shader editor to create different UVs for curves without needing to convert them to mesh/unwrap them first (I'm doing hair cards, all the cards are on one texture). Is there a way to apply the transformations I'm doing in the mapping node to the UVs once I've converted the curve to a mesh? Usually when I use this technique I'm baking the texture to UVs I've handmade, but now I want to do the opposite, keep the texture and "bake" the UVs. Is that possible?


text:
Why does my OBJ import has a white transparent overlay in Material Preview
I am really new to Blender and 3D in general. I have imported an OBJ of a wooden water rower in Blender to make a quick assembly animation. Initially I imported a STEP file into Adobe Substance Stager to add textures to all the parts and then exported it to OBJ.
In Blender, I see in the Solid View with the 'texture' color on how it kind of should look, like this:

However, in the material preview and render preview, it appears to have a white transparent overlay over the model.

Anybody know what I might be doing wrong? Any tips are welcome. Thanks in advance.

You need to show us the Shader Editor in order to see if the materials are correct. Could you please pack the images and share your file?

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

@moonboots Hi really appreciate you want to take a look at it. Please find the Blend file here: https://drive.google.com/file/d/1GMew2MchoMPeUGv1mvy2E_X-xyRdfN2f/view?usp=sharing
It should have all the images in it. Let me know if it works. It's part of the 3D model, because I can't share the whole file. Thanks again!

The Emission color needs to be black, or put the Emission Strength at 0, otherwise the surface will appear white:

Perfect! This worked. Thank you so much!


text:
Randomizing Instances Geometry Nodes
So I built a geometry node setup that lets me build houses out of different shapes I made.In my geonode setup I just put all the parts together dependent on size and all.

And now I want to use that group to make different buildings on a grid but so far I only get the same instance back.Is there a quick fix or do I need to set up every house variation myself.

In your screenshot you only have one set of geometry that can be instanced on your points. You can use the Geometry to Instance-node and multiple copies of your group to create more variants:


text:
Why does my armature stretch when moving/rotating
I'm fairly new to Blender and don't really know the intricacies of how blender does things. I'm trying to rig this model. I have the body as an object and the head as a separate object. I have a simple armature setup.

When I rotate the head armature, the armature seems to stretch along with my mesh object. I don't know why this is happening. as I don't want any deformation on the object and should just rotate as a whole.

I've tried:

Playing with different vertex groups and weights
(I've set a value of 1 to the head bone and 0 to all others)
Attaching the mesh object directly to the bone as a parent
Selecting/Deselecting the "Deform" option on the bone

Thanks

Probably, because the armature has unapplied, non-uniform scale, or the armature is ultimately parented to something that does.

since you didn't show us any useful information like armature settings and so on...pls provide blend file so we can check it out, thx

As Nathan says, select the armature in Object mode and press Ctrl A (Apply) > Scale and it should fix your problem

@moonboots Thanks boss, that indeed fixed it. If you don't mind can you quickly do a explanation what I just did?
Thanks

You must have scaled your armature before, we can see that the bones don't have their normal scale. If you do that it will stretch the mesh in an undesired way. In order to give  back a scale of 1:1:1 to your armature but keep its current size, you need to scale, see a tuto on this topic, maybe this one: https://www.youtube.com/watch?v=DK0_FH7miEQ

Thanks, that makes sense since my armature looks like they're different sizes


text:
How to find the end point in a mesh line. Blender Geometry Nodes
I am attempting to create a dragon curve in Blender Geo nodes via duplicating and rotating a mesh line repeatedly, similar to this gif I found on wikipedia (without the beveling): https://en.wikipedia.org/wiki/Dragon_curve#/media/File:Dragon_Curve_unfolding_zoom_numbered.gif
The Main Issue
I cannot find an easy way to locate the 'end' point in the mesh line, as shown in the gif. I've tried many different solutions, but all of them have failed. I check stack exchange multiple times and could not find a solution. I have hit a brick wall in terms of my very limited toolkit as I am quite new to Geo Nodes, and am still getting my footing. Feel free to ask further questions for more clarity on my part. Here are a few images showcasing my admittedly small problem.

Thank you.

Hey, I know that there's already an answer, but just to let you know, Default Cube has uploaded a tutorial on this. https://youtu.be/gigIzivJkxk

Example for independent study:
The generation method is to remember the start and end points, and overwrite them correctly for the next iteration.

A simple and performant way to detect if a vertex is the "end" is to simply check the number of edges connected to it:

But how would I find the position of those points?

@Dreadward07 to find the position of them is an XY Problem, you need to explain what is your end goal, because the most immediate answer to your question is simply: use the "Position" node.

Apologies, I should have made it clearer in my original question that I needed to return a vector for the end points.


text:
Help with adding 'ribbing' to a 3D Modelled horn
So I'm trying to add 'ribbing' to these horns, I know I can manually go in and just create the geometry, but I didn't know if there was an easier method for adding that kind of detail to a model?
The horns have been created by starting with a cylinder, and just extruding it to shape then I've added a level 2 subsurf modifier to it, so I can get a better idea on how it'll look
Any advice would be appreciated!

Read: modeling a twisty tree, how do I twist a beveled curve

https://www.youtube.com/watch?v=1drRNphACMc

Ahh thank you, I shall give this a go =)


text:
Weird black lines in render
When I render this image, there are these black lines on the arms that only appear when it's finished rendering. Anyone know what can cause this?

They kinda look like freestyle lines.... but I know nothing about that


text:
Mask cables in footage and change its color
I have a charge cable in the footage which I want to track the cable and change its color, here is how the footage looks like from the very first frame to the last frame:
The red point is where I want to put my tracking markers on

What I want to do is to re-construct the cable by using the dot on the cable, by re-construct the cable, I mean I want to connect the traking markers by curve/path then use the Geometry panel to set its Bevel depth in order to overlap the cable in the footage, now I have some problem,
I know how to do point tracking, I use makers on the real cable and I can track the markers, but how to connect the tracking point in Blender on first frame, then connect them by curves to re-construct cable, then go to the second frame and so on.
2.Is it reasonable to do the cable re-construct by this way, or is their other easy workaround?
Thanks!

I'd put small black dots along the cable, track the dots, then use the point field to get the locations of where the curve points should be. Snap the cursor to the different tracking marker empties and then move the things to the cursor.

Can you elaborate a little bit about what is point field

Sorry was short on time when writing, basically when you start a new file in blender with VFX mode and import then track your footage. After solving it you will see a bunch of points. Select one in the 3d viewport and then right click and select snap. Snap cursor to selected. Then in the curves edit mode just use the 3d cursor as a guide for different points the curve needs to move along. From there you should be able to render a mask or to selectively recolour by rendering in black and white or with alpha or something.

Thanks, I will take a try getting home!


text:
Bake combined doesn't give me Normal information?
I might be confused when baking combined, all I got is this single image on top-left after baking, but where is the bluish Normal information in this image?

I might have misunderstood the combined baking, how can I got the normal information from this single combined image. As far as I know I can create low poly to bake normal from high poly, but when baking combined, if I do not have low poly, then what is the point that having Normal Pass in Combined Bake Type? Thanks a lot!


text:
Baking Groove on mesh results in black color
I'm baking an object with groove on the surface, but after baking, the grooved part shows black, and I do not know why, my node step is as follow,

Sorry but this a stupid question, cause I engraved the text on the the sphere, I need to re unwrap the mesh, otherwise there will be uv coordinates and will results in black


text:
how to re-use noise texture from geo nodes in (volume)shader
I'm trying to use the same noise data from geo nodes in a shader for its volume output. I fooled around with named (color) attributes but this will obviously be geometry based and not volumetric data anymore - is this possible at all? I'd like to avoid recreating the geo nodes  noise in the shader to keep it fully procedural


text:
Textures not showing properly in Cycles. Is there a fix to this?
Newbie here. I'm having some trouble with using Cycles, and am not sure how to fix it.

When in the 3d viewport, textures show up fine when using Eevee. When switched to Cycles, the textures seem to disappear at random spots and changes when I tab in and out of the viewport.
Where could the problem be rooted?

Can you share the file? https://blend-exchange.com/

It may be overlapping faces (it causes Z fighting), try to merge the vertices in Edit mode: press M >Mege by Distance


text:
Cannot export texture correctly, because I scaled it
OK, so I've been using the shader editor, to scale a texture, with the texture coordinates, vector mapping, and image texture nodes. But when I look at the uv editor, the texture looks the same. It is scaled on the model, but if I export it as fbx, it looks like the texture was never scaled, even if I embed the texture. How can I export the scaled texture?

Fbx format only supports very basic textures. See: https://blender.stackexchange.com/questions/57531/fbx-export-why-there-are-no-materials-or-textures for a full explanation.

The UV Editor shows the image texture, and the UV map is mapped onto it from bottom left (0, 0) to top right (1, 1). Everything you do with a Mapping node in the Shader Editor is a procedural post effect manipulating how the texture is placed on the UV map (or the other way round?), it is not changing the actual UV layout. FBX does not support most of the Blender specific nodes (like Mapping), so if you want to scale the texture for export you cannot do it procedurally, you have to change the actual layout in the UV Editor so that it matches the desired result without Mapping node.

As mentioned in my comment, the FBX format does not support many of Blender's nodes, in your specific case the way you manipulate the texture with a Texture Coordinate and Mapping node is lost when exported to FBX.
Looking at the UV Editor does not show the changes from the Mapping node, because as the node setup already suggests, the Texture Coordinate node outputs the UVs which are then manipulated afterwards with the Mapping node - the changed UVs are not written back into the UV map if you know what I mean. In this way, the Mapping is a procedural effect like a Subdivision Surface modifier, which does not actually change the original underlying mesh but only the visible appearance.
Now you might want to know what you can do get the same mapping of the original UV layout when you cannot use the Mapping node. This is quite easy when you have the values of the node.
In the following example I use a texture as bump map. Let's say I scaled the UV map by a factor of 3, moved it 0.2 m on X and 0.7 m on Y. Then the mapped UVs look like the cube on the left side, and the original UVs without any Mapping node look like the cube on the right side:

In order to make the right cube look like the left one first of all make sure the Pivot in the UV Editor is set to 2D Cursor and the cursor is in the bottom left corner (should be by default), to verify this you could open the sidebar with N and under View > 2D Cursor make sure Location X and Y are both set to 0.

Now you have to apply the values that are set in the Mapping node to the UV map. It is important to keep the correct order: 1. scale the UVs and 2. move the UVs.

Select them all with A if they are not already selected. To scale them by a factor of 3, press S3Return.

Now you can move them by the according values in X and Y direction by pressing GX0.2Return and GY0.7Return. And the result now looks exactly like the cube on the left.

If your mapping has different Scale values for X and Y you can of course scale them separately as well like you are moving X and Y separately, as long as scaling is done before moving.
Since a UV map is 2-dimensional, the Z component is not important for these operations. However, if you also rotated the UV on the Z axis with the Mapping node, you can replicate this in the UV Editor as well (and only Z rotation, since X and Y distorts the UV in 3D space which I do not know how to achieve in 2D).
The important part is, rotating also has to use the 2D cursor as pivot and most important: it has to be done before all the other translations. So it is 1. rotate, 2. scale, 3. move. And contrary to scaling and moving where you can use the same values as in the Mapping node, for the rotation you have to use multiply the angel by -1 to get the correct result. Here in the following example the Mapping node is set to a value of 45°, so in the UV Editor you have to rotate by -45° by pressing R-45Return:

Now you can go on like before scaling and then moving the UV map and the result on the right cube will again be the same as on the left cube:

If I may ask, does your example only support scaling down, to make it smaller, or will the uv editor make more texture if I scale it up.

@Geichelb3512 I do not know what you mean by "make more texture". The texture is a single image of a fixed size in pixels. Scaling the UV (larger or smaller) only determines how often the texture fits onto the object's faces and thus how often it is repeated and/or how large or small it looks on the object.


text:
Per Object Attribute not updating instantly
I am using this code, based on a previous question:
https://blender.stackexchange.com/a/302335/171509
import bpy
Color_Node_UID = "Test"

obj = bpy.context.selected_objects[0]
obj[Color_Node_UID] = (1.0, 0.0, 0.0)
ui_prop = obj.id_properties_ui(Color_Node_UID)
ui_prop.update(subtype="COLOR", min=0.0, max=1.0)

Which will create the custom attribute for this specific object:

In the shader I have an attribute node, named Test:

But in the viewport it is still black

Do I open the color picker and change anything it is updating correctly:

I already had the same issue here: https://blender.stackexchange.com/a/298953/171509
The solution was to have an empty lamda in the FloatVectorProperty:
bpy.types.Object.custom_color = bpy.props.FloatVectorProperty(
    name="Custom Color",
    subtype='COLOR',
    default=(1.0, 1.0, 1.0),
    min=0.0,
    max=1.0,
    update=lambda self, context: None
)

But I just can't figure out how I can get the update lamda in the id_properties_ui.
ui_prop.update(subtype="COLOR", min=0.0, max=1.0, update=lambda self, context: None)

Errors with:
Python: Traceback (most recent call last):
  File "\Text", line 9, in <module>
TypeError: 'update' is an invalid keyword argument for update()

Would be epic to get a hint.

This hack works, but I am not sure if this is a good approach.
https://blender.stackexchange.com/a/258030/171509
`
import bpy
Color_Node_UID = "Test"
obj = bpy.context.selected_objects[0]
obj[Color_Node_UID] = (1.0, 0.0, 0.0)
ui_prop = obj.id_properties_ui(Color_Node_UID)
ui_prop.update(subtype="COLOR", min=0.0, max=1.0)
obj.hide_render = obj.hide_render
`

I think ui_prop = ui_prop will fire the update callback


text:
Can't make Bevel Modifier working on engraved mesh
I'm trying to bevel the mesh with bevel modifier, for the text area marked red, but the modifier doesn't work,

Even if I apply the bevel modifier on the whole mesh in object mode, it doesn't work either,

I don't know what goes wrong, what I want to achieve is to bevel the engraved text area, to make it smooth.

This has to do with the bool operation (I assume) you performed to get that "engraved" look. If you look now, the top of your mesh is split into (what looks like) 2 large faces, each with a large number of vertices that are unconnected from the inner edge (text) to the outer edge (side of the "block"). Essentially, the top faces of your mesh are large n-gons and blender prefers quad based topology (4 verts per face) in order to function properly. This is why you cannot bevel.

If I take a closer look, it has very little bevels, but the width is too narrow to be seen, even the width set to 100m

Turn off the “clamp overlap” in the modifier. This has gotten me a few times too.

Yes, but it will cause face overlap

It’s an existing problem in blender that may have a solution but I don’t know about it. It’s kind of a geometric problem when two outward corners intersect with one inner corner.

Come to think of it, that’s a question worth asking. I think I’ll delete my answer, and go ask it now, or you can?

Leave this answer here, cause we can use this solution if tiny intersected faces are less important


text:
Bake textures in cycles and and used in Eevee vs Light Probes
I'm wondering what is the differences between these two approaches,
I managed to bake in cycles and used these textures in Eevee, and it looks almost the same, then what is the benefit of using Light Probes in Eevee? Only for animation? If my scene i static, does that mean they are exchangable?

I think it's a high, middle, low situation here. Real time raytrace in Cycles would be the slowest approach but would track real-time light movements. EEVEE with LP would be the middle ground solution, because even though it is a "baked light" operation, it is calculated significantly faster than cycles, and is therefore suitable to be baked on a per-frame basis (without the need for a render farm) Lastly, for scenes with truly static lighting, you can go either-or depending on your render engine of choice - Cycles is more realistic but slower - EEVEE with LP is faster, but still approximated.


text:
How to clean up the mesh around the holes?
The holes are connected with the edge, how to remove it, when I delete the edges marked red, the whole face is gone, I do not know why the face is gone, and how to clean up the mesh, at least make it a little nice.

Another question is how to erase the bevel, to make it 90 degree, as you can see I want to connect face 1 /2,2/3,1/3 and remove the messy bevel between these three faces.

In the second picture, i suggest you create a cube mesh that has dimensions similar to that of lengths of faces 1,2,3 and then align the box to the beveled mesh (enable Preferences: Add-ons: "Align Tools" to access in the Tools, Align area (to align location, rotation, scale)... would be the easiest to "get rid of the bevel".    Otherwise you might try to use Edit mode, select one of the bevel faces, then Select -> Similar -> Area, and delete faces, but you'd have to do this for several iterations and then be left with a cleanup of editing and moving the vertices related to faces 1,2 and 3.

Please ask only one question per post. For different and unrelated questions open as many posts as you need.

I think I have to manually do some operation on the mesh to construct the clean mesh, no easy way


text:
Shading artifact after rendering
I'm now working on a model, it looks fine in the view port, but grey part Shading artifact after rendering to image, here the first screen shot is wire frame, and the second image is rendering result it looks wired, can anyone tell me why? And what strange more is ,when I move the model a little, the artifact gone, I've got no idea what could be the reason.

You said moving it fixes the problem could that mean you accidentally duplicated the object and there's a second one with the same mesh causing z-fighting? Try selecting and deleting it to see if it fixes it.

The problem is happening because the Bool operations are leaving your 2 top faces as massive n-gon's. You will have  to re-topologize manually to convert the mesh back to primarily quads. A pain - I know, but bools are notorious for leaving messy topology. Fixing it will solve the shading errors.


text:
Baking combined vs baking individual map
I am confused with the combined baking mode, the combined mode has every map combined together let's say normal map, usually, I bake single normal map from high poly to low poly by creating low poly in advance, but when I want to bake texture, I do not have the low poly created then my question is, what is the difference between the combined mode normal information and a single normal map?


text:
How to draw true coordinates system in Blender without creating geometry
I want to do a math animation using blender, so I need to create 3D coordinates including the X,Y,Z line, however, I can only create the axis by creating real geometry, like a very long cylinder to simulate the x,y,z axis, the disadvange is when zoom in and out, the axis will change and this is what I do not like, what I need to have is to draw x,y,z axis like the built gizmo, that looks the same independent of the view distance, and has its own color represent different axis.

I think you have the right term, unfortunately there isn't a lot of information on how to create blender gizmos out there. You'll have to use python to code it. You can take a look at the blender API https://docs.blender.org/api/current/bpy.types.Gizmo.html

yes, I will be using Python it is fine, I will take a look


text:
Why data can not replaced with types.BlendData
I'm reading the Blender API, when I came to this line:
data = types.BlendData

I realized bpy.data is a short hand of bpy.types.BlendData, so I tried to change my code from
mesh = bpy.data.meshes.new('mm')

to this one
mesh = bpy.types.BlendData.meshes.new('mm')

and I got this error
AttributeError: type object 'BlendData' has no attribute 'meshes'

Can you tell me where I was going wrong?

Hello, meshes is not a static member of the bpy.types.BlendData class. You need to access it through an instance of the class (bpy.data). I don't think this question is suitable for this site. It really is more a question about python rather than Blender which can easily be answered on stackoverflow or by following a crash course on python. Cheers

Thanks, but I could not find where the bpy.data is instantialized , it is a bit related to Python though

I think you're misunderstanding the features of the python API, most of what you get in Python is just handles for objects that are in fact initialized behind the scenes by the c++ source code. You might want to dive into the source code rather than the API if you want to have access to these calls


text:
Confused with chained Python script when creating data block
I recently dived into Python Blender scripting, while reading the Blender API some Python script got me stuck, I couldn't understand it, I can make it work though, here is the code from Blender API,
# Create new object with our light datablock.
light_object = bpy.data.objects.new(name="New Light", object_data=light_data)

The line bpy.data.objects.new(), Why 'data' can be chained after bpy? I'm sure 'bpy' is the module name, is '.data' and '.object' a method returning 'self' or is it a class name?
The menu said the 'bpy.data' is type of 'bpy.types.BlendData', I can not wrap my head around for this Python syntax, can you shed some light on what type of each section of the code really is so I can use the right term to search the syntax

Hello, a small heads-up : If you want to maximize your chances to get some help here you either need to take a crash course on Python, or define more clearly what you intend to do with your scripting. Cheers

Although I don't understand what you're doing, I know that the approach you're doing throws an error. If you go to the default scripting widow, at the bottom left it shows all the API calls you have done so if you shift+a>light>point, it will show
bpy.ops.object.light_add(type='POINT', radius=1, align='WORLD', location=(0, 0, 0))

And sure enough, if we run it it will create a light.

If the line light_data = bpy.data.lights.new("Foo", 'POINT') is run before hand code in Q creates a point light


text:
How can I customize the appearence of the node in node editor
I want to change the node in node editor to triangle shape, or any other shape I want, not a quad shape node as default, and the port on the node is a dot, I need also to change it to some other shape.
Can you suggest me of a practical approach to achieve this? Is this possible to use the Python api or should I go to the blender core?

You'll have to build your own Blender.

Are you saying a blender of "my" version

To answer the question, it's not possible with the Python API and you'll have to mess with the source code in C / C++


text:
Smoke simulation set to outflow, the smoke still interact with the ceiling
I set the flow type to outflow, it's supposed to be not interacting with the ceiling as the Blender Manual says, the ceiling will be acting like a black hole, however, below is my screen shot and I can observe the ceiling is colliding with the smoke, why is that thankyou !

please provide blend file....the screenshot doesn't help at all in this case

@Chris I posted an answer

It's strange, I do not know if this is the intended design, everytime I change the setting of the flow, I need to re-select the "replay" item to make it valid as shown below,

The issue I came accross resulted from the cache from the previous settings not freed up until I re-select the "replay", so this is my solution.

The cache type Replay is kind of a "on the fly" simulation, and sometimes can be screwed up if the cache isn't freed correctly. I usually don't simulate with Replay because if I set a little more than the default domain resolution it becomes too slow in my viewport. But that's of course dependent on your hardware. I prefer Modular or All and maybe enable Is Resumable. Then I can hit "Bake" or "Free" to simulate or get rid of a simulation. Just for testing and checking settings it doesn't even take long if you're still on a lower resolution.


text:
Camera solve, align the 3D space with the footage
I'm adding the 3D object into the footage I shoot, after camera solving I got error 0.28px which is pretty good, then I want to check if the angle is correctly aligned with my footage so I put a long vertical cube and check if the edge of the cube is in parallel with the edge I have in the video clip, then I got bellow result,

Then I rotate the camera to solve the issue which I got this

My question is,
Do you in your workflow needs to align the camera solve with the footage like what I did? By putting a long vertical thing to check if it matches the footage? Why my camera solve error is pretty decent but still it has such huge misalignment? And do you also needs to algin the grid to the edge of the wall?


text:
Convex torus/curve
I'm getting stumped.... I've sent over several different versions to the client, and he doesn't seem to like any of them.  I'm attaching the reference image here.
.
I have tried working from a torus and cutting it up, as that's how the client has also described that interior section (green).  He says it's wrapped in a cube or cylinder (clearly not a cube in the ref.).  I wrapped it in a cylinder.
Here are a couple images I've sent to the client that have not passed muster...

Any thoughts on how to get a blobby, convex-ish curve inside another curve like this?
Thank you!

Just a curve (circle part) with bevel objects:

To do it this way, you can:
Create a mesh circle, remove some vertices and convert it to curve. That may look like this:

Also starting from meshes (as this is more simple in my opinion), create the profiles and also convert them to curve. That can be:

Now duplicate the circle above and assign to each circle curve a bevel object:

 (Blender 4.0)

That looks great.  I don't understand how you did this with just a curve and beveling though..

I will add some details

What you show looks like that:

To do it, create a cylinder, inset one of its cap faces:

Remove all these faces:

Select all and extrude along normals, activate Offset Even:

Duplicate these faces:

Extrude them:

Create an edge loop, scale its inner edges:

Bevel it, etc:

This answer is a bit spare on details. Could you elaborate on how you achieved it? Describe what tools or modifier you used perhaps

@Duarte Farrajota Ramos sure it lacks details, I thought the original question was about what shape it is supposed to be

The shape seems clear to me at least, I interpreted the question as asking how to model it, otherwise it would seem off topic here. Thanks for the update, seems much better now

Yes, it was about how to model it.  Lemon recreated it nicely, but have no clue how he did it.  Moonboots has provided a good step by step, along with helpful images.  I don't have the "rep" on the site to upvote, but great answer.

Somewhat separately, I now have to apply materials/textures, and am not sure how to create the separation needed, as it's all one object...


text:
Aerogel material in Blenderkit - having a little trouble
This is specific to the aerogel material from Blenderkit, so not sure how many others have experience with it, but maybe someone more experienced with Blender would still have some ideas.  I lucked out in finding it, because I actually need to use an aerogel in an image, and was really unsure how I was going to create it.  However, rather than simply conforming to the mesh I'm applying it to, it seems to stray a LONG ways.  I have a plane I applied it to, as I only want a thin layer, but it's "misting out" into nearby meshes, and making the image look pretty bad as a result (I love the effect, but for the current project, it really won't do).
Current render:

You can see it almost looks like I created a giant cube, but no, that's a plane.
I'm not too experienced with using nodes in the composite editor, as I only recently got a new laptop capable of using a newer Blender version (currently on the newest).  Maybe there's something I can do with that?  I hope this doesn't sound like too much of a newbie question...  Another note, is that I get very different results with different rendering engines.  Everything else is pretty much the same, but the aerogel is incredibly different.  In case it helps determine what's happening, I'll post the other renders.  The first is with EEVEE.
Then there's this with Cycles:

Doesn't even show up, oddly enough.
And workbench:

I had no idea what an aerogel is (and what the is the Knudsen effect?)... well, never mind, judging by the screenshots, the material uses a Volume shader. Check the material. There at least three of them (Principled Volume, Volume Scatter, Volume Absorption) These shaders don't work for planes because planes don't have any volume. Try a Solidify modifier to add thickness to the plane. 2) Eevee can't render volumes very well ->"cube style". Better use Cycles.

To add to what @Blunder meant at the end: EEVEE cannot show a volume shader in the shape of a mesh, it will be a cuboid the size of the object's bounding box. For mesh-shaped volumes you need Cycles.

Brilliant, thanks @Blunder.  This, indeed, solved the problem.  Feel free to post as an answer.  I added a bit of volume with the Solidify modifier, and rendered with Cycles, and am now getting the desired output.

Judging by the screenshots, the material uses a Volume Shader. Check the material nodes. There at least three of them Principled Volume, Volume Scatter, and Volume Absorption.
These shaders don't work for planes because planes don't have any volume. Try a Solidify modifier to add some thickness to the plane.
Note that EEVEE cannot show a volume shader in the shape of a mesh, it will be a cuboid the size of the object's bounding box. For mesh-shaped volumes you need Cycles. (– Gordon Brinkmann)


text:
Engraving displayed from two sides
I am trying to engrave an image to the bottom of an object. The problem is that it ends up projecting both on the bottom and the top.

My nodes look like this:
I think the problem is in UV editing. When I look on the object from the bottom and project it from view, the top is also displayed, like so

I've tried only selecting the bottom of object when projecting, but the result wasn't changed. Thanks for your help.

Select everything but the bottom and in the UV Editor, move and scale the UVs in order to place them over a part of your image that has no signs.


text:
Cut mesh into two objects along selected edge
I want to cut the mesh along the blue line,I've tried different ways, with no luck

If I select the 4 edges then press P, then I get a Square shape rather than a mesh, I saw tutorial says edge split in Edge Menu can do the job, but I'm using blender 2.9 there is no such item in the Edge Menu, I dont want to use a plane cut either cause the mesh I'm cutting is a rare case that the edges forms a plane, I want a more universal way of doing this in case of the edges does not falls into a plane.

No worries, the split option is still there :)

Select your edge
Go Mesh > Split > Faces By Edges
Done.


text:
Don't understand why holes needs to be connected to edge
These are two holes I cut by using bool tool, my question is why the edges 1,2,3 are necessary, I have a rough idea that all the shape needs to be at least N-gons, so if there is a standalong hole without any connection to the mesh, it is not allowed, but why should we follow this rule, in other words,
1.why the feature is designed in such way, is this reasonable or not, I think this question will help me better understand the mesh, so thanks in advance!
2.Is edge 1,2,3 has to be at the same location as shown on the screen shot? Can the edge 1 replaced by edge a?

it's just the way blender's topology system works. I don't know any of the code behind it so I couldn't really tell you the reasoning behind it, but yea.

Related https://blender.stackexchange.com/questions/227436/why-cant-i-dissolve-this-edge https://blender.stackexchange.com/questions/210059/is-there-any-way-to-remove-edges-causing-a-loop https://blender.stackexchange.com/questions/211241/dont-understand-why-holes-needs-to-be-connected-to-edge https://blender.stackexchange.com/questions/48954/eliminating-edges-connecting-islands

There's evidently some critical conditions that an ngon can't exist under.
If you take an example with only one hole, you'll see you are completely unable to dissolve these edges.

When I cut two holes I got a different result from you, and I was unable to dissolve any edges.

Until I added a new edge in the center like you have, and then you are able to dissolve a couple.  I get one less edge than yours.

But each of these remains a shape with a definite inside and outside, and that allows a face to be constructed from it.
I'm unaware of the exact limits placed on ngons, but my best guess is that these are very close to the simplest shapes possible that still allow you to draw triangles without drawing through an area where the mesh shouldn't have a face.

(I kind of misplaced the X here, maybe)
You can use a Triangulate modifier in Wireframe view to visualize.

Thanks for the answer, one thing I could not understand is what do you mean by leaking out into space that should be open

I've edited to state "without drawing through an area where the mesh shouldn't have a face."


text:
How to align pivot to the center of a hole
I've got a button model, that is supposed to be rotate around the pivot point in the center,

But how to set the pivot point to the exact center is a problem, the center should be further into the hollow area
I know this model is simple and if you create it from a cylinder the pivot is what I want, but I want to know if say I got model from other people and the pivot is not in the center, how can I align it to the center,thanks.

In Edit mode, '2' for edge select then ALT-click on the top edge round the inside of the hole and SHIFT-S > Cursor to Selected.
If you want it half way down the hole, go to Face mode, ALT-Click one of the edges inside the hole to select the ring of inner faces then SHIFT-S > Cursor to Selected again.

This is pretty nice solution!

Adding to John Eason's answer: don't forget to set your pivot point accordingly Numpad . > 3D cursor
You could also pivot around the object's origin: Numpad . > Individual origin
But then you also have to set the origin correctly: After setting the 3D cursor in Edit mode, you can set the object's origin to the 3D cursor when you're back in Object mode (right click > Set origin > Origin to 3D cursor).
Also helpful in this regard are constraints, e.g. a Limit Rotation constraint so you can only rotate the knob around it's z-axis. Also limiting the amount of rotation is possible with that constraint.

Thanks for your answer, I tried to setup the limit rotation constraint, but not working, so I opened up another thread: https://blender.stackexchange.com/questions/211673/trouble-with-local-space-limit-rotation


text:
Trouble with Local Space Limit Rotation
I set the limit rotation, but the constraint not restrict the rotation, here is my setup,
I can still freely rotate the object in all axis,

So I tried to tick the affect transform option, but it gave me strange result, as long as I press the R key. it reset my rotation to like this,

It should've been restrict the rotation based on the current object rotation, but it reset my rotation to the world rotation.
So how to limit rotation in local space, thanks!

When trying to transform, eg rotate with R with affect transform checked, settings above  ultimately are restricting  local rotation to range of (0, 0, 0) .  If the object has no parent then local is global.   Make the rotation range settings in the constraint contain the current values to use this setting and not lose your current rotation values.

Restrict local rotation to 0,0,0 should make it stay still as the first screen shot, but it doesn't, I don't know why, because local rotation is now 0,0,0

Still confused to me, when I rotate the object in world space by 55 degree in x axis, the local space rotation should remain the same which is no rotation at all, I do not understand why you mentioned local is global if there is no parent.

Because local rotation is relative to the object itself, how much it rotated in world space should not change a bit in local rotation

Local from local matrix, world  from world matrix  https://blender.stackexchange.com/a/169424/15543

Object constraints don't handle local space correctly when they don't have a parent.
But, that's a problem with an easy fix, because objects that are unparented exist in world space.  So for your unparented object, you can change the space in which the Limit Rotation acts from local space to world space.
You specifically ask how to limit in local space, although it's not clear what your end goal or actual problem is-- this looks like an idealized situation.  And it would be easy to imagine some misunderstanding of what limited local space rotation would look like.  If you want an explicit answer to how to limit rotation in local space, then make an empty at the world origin and parent your object to it.  Now, you can limit rotation in local space if you want.  It's just, that's exactly the same as limiting rotation in world space.

Your solution is nice, I need to parent it to object!


text:
Blender python, what design pattern the Operator class is designed
I'm new to Python scripting, and is confused with the design pattern it's used so I do not quite understand how this class works, here is a code example,
class HelloWorldOperator(bpy.types.Operator):
    bl_idname = "wm.hello_world"
    bl_label = "Minimal Operator"

    def execute(self, context):
        print("Hello World")
        return {'FINISHED'}

From the execute() function, how this function is called by Blender and where this 'self' and 'context' comes from remains a mysterious, it has to be somewhere in Blender to call this function.
To sum up a bit, the user defines the real function (the function to be follow a predefined pattern, the function name pattern, the return pattern etc.), then being called by Blender, what design pattern this is?

The HelloWorldOperator derives from the bpy.types.Operator base-class.
The self variable is a Pythonic class pattern, it is similar to this in C++ like languages. The class variables declared in the class header, e.g. bl_idname and bl_lable, are shared across all instances of the class. The self dictionary contains the per-instance variables and is always the first argument in a Python class method. It is automatically supplied on method calls.
The context comes from the Blender environment and contains pointers to the active object, collection, GUI mode and other things.
Classes deriving from bpy.types.Operator are high-level functions designed to be used as GUI callback functions. As such they only return GUI status.

Thanks for the heads up, where I do not understand is "to be used as GUI callback functions", is there any pure Python implementation of such pattern I can refer to, so I can have an intuitive   understanding of how this call back is called

Have you read https://docs.blender.org/api/current/bpy.ops.html?


text:
Bake mesh to plane results in flipped image
I'm trying to bake the top face of the cube(with text) to the upper plane like below,

Then I place the plane on top of the text and do a ray cast,

The end result is a flipped over result,

I'm curious what happened, I used to bake from high poly to low poly, but this is the first time I bake a chosen high poly face to a plane, could you suggest me a right way of doing this, thank you my friend, I just want to bake a simple decal.

Seems like the uv shell of the plane is flipped. Try scaling the shell in the uv editor in -X.

Thank you so much, but is it the plane's uv is flipped by default?

Shouldn't be the case, I've hat flipped uv shells when making Cube Projections.


text:
Alpha channel set to below 0.1 results in invisible object
I encountered a problem I do not know why when creating image in Shader Editor,
I set alpha value between 0<=Alpha<0.1 in Shader Editor, the object is invisible from texture Paint mode, as seen below,

But if if set Alpha>0.1, the object become visible as shown below, but it colors blue

So I don't know why it become invisible if alpha value less than 0.1

Shaders typically have a clipping value set for low alpha values. If the alpha is below the clipping threshold, the pixel won't be rendered. This is an optimization which helps speed up rendering and can help give sharper transitions on textures with transparency.

This makes sense however I can not seem to find this is stated in the doc.


text:
How to round a plane to a sphere surface
I'm going to make the top face of cylinder to a sphere like curved surface, like a cap on top of the cylinder, I've searched a lot but everything I found is round an edge rather than round a surface
From this

To this kind of shape

Thanks.

Can you not create the domed top first from a UV sphere by deleting the lower section to get the form you want, then select the bottom ring of vertices and extrude them downward to create the cylinder section?

It is a good idea, I will try that

c If you then want to alter the curve of the top, you can select the top centre vertex and use proportional editing to alter the profile of the dome as you wish.

How to get a top center vertex, my cylinder does not have a middle vertex

use inset (i), scale down, then create additional edge loops with Ctrl B (bevel)

If you start with a UV sphere as I suggested,  press 'O' and then select the top centre vertex of the remaining part of the sphere which has created your dome. 'G'rab and move it on the Z axis using the mousewheel to alter the curve of the dome.

I guess the easiest way is to extrude and bevel. You can tweak the shape in the Operator box, or scale later on the Z axis:

You can also customize the profile of the bevel in the Operator box:

To illustrate John Eason solution, you can inset your top face (i):

Then bevel (CtrlB) to create additional edges:

Enable Proportional Editing (Sphere mode) and move up the central face:

Tweak the parameters in the Operator box if necessary:

This seams like a good workaround, I am wondering if there is more official way to get the sphere top

you can work the other way around: create a sphere, delete its bottom half, extrude down to make the cylinder

Yeah just like @john said, I will have a try