text:
Build Blender as a Python module with Draco compression enabled
I've succeed in building Blender as a Python module, but I would like to be able to use the draco compression when exporting glTF (gltb) files.
When building Blender as a Python module, I set CMake flags as indicated on the official wiki https://wiki.blender.org/wiki/Building_Blender/Other/BlenderAsPyModule:
WITH_PYTHON_INSTALL=OFF
WITH_AUDASPACE=OFF
WITH_PYTHON_MODULE=ON
WITH_INSTALL_PORTABLE=OFF

But, in the CMakeLists.txt there is an incompatibility between WITH_DRACO=ON and WITH_PYTHON_INSTALL=OFF :
if(WITH_DRACO AND NOT WITH_PYTHON_INSTALL)
  message(STATUS "WITH_DRACO requires WITH_PYTHON_INSTALL to be ON, disabling WITH_DRACO for now")
  set(WITH_DRACO OFF)
endif()

And WITH_PYTHON_INSTALL=ON is incompatible with WITH_PYTHON_MODULE=ON:
# python module, needs some different options
if(WITH_PYTHON_MODULE AND WITH_PYTHON_INSTALL)
  message(FATAL_ERROR "WITH_PYTHON_MODULE requires WITH_PYTHON_INSTALL to be OFF")
endif()

Is there any way to have Draco enabled when building Blender as a Python module ?
Thanks

did you ever find a solution to this issue? Anyone know why WITH_DRACO requires WITH_PYTHON_INSTALL to be ON? It's still the same situation with the latest Blender 3.6 LTS release.

I guess one simple solution is to do a regular GLB export and then use another lib like this: https://github.com/seung-lab/DracoPy


text:
Composite glare overlayed by alpha transparency of other material?
I know the discription is a bit weird, but hear me out: Look at the image. I put a glare filter on the 2 red eyes, but it doesn't shine through the part of the shiny triangle that's supposed to be transparent. How can I fix this? I hope I explained myself well enough xD[

Can you post a screenshot of your compositor setup?

Sure. One moment...

Solution 1:
You might want to switch the blending mode from 'add to 'screen'

Solution 2:
Instread of a mix node you can use an 'alpha over'. to my experience this works better for more complex overlays with multiple colours. make sure you add the alpha channel to the 'alpha over' node or it won't work
(in your case you would take the alpha from one of the 'ID masks', not the alpha from the image)

The "screen" did work a bit, but the glare still did not go through it completely. Do I maybe have something to do with the material that has the alpha transparency on it?

It might require you to switch the input images depending on what should be the top layer (in this case the glare) It should work though.

Wait, the glowing of the glare does seem to go through the transparency, just not the extra light from the glare on top of the eyes... I'm a little lost actually. The other solutions didn't really work.

source: Stack Exchange

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

sort: votes


text:
How can I make objects duplicated by script to have manipulated properties which are different from properties of the other duplicated objects?
I am no beginner of blender and python but I have a problem and therefore a question which couldn't be solved with help from all other internet pages.
My problem:

I have put one object in another layer to be duplicated several times by scene.addObject(). The duplicates show up in another layer perfectly. I have one object checking for collisions. The duplicates are 'spawning' on the object which is checking for collisions and my created dictionary-variable will be the .hitObject of the collision checking object. For example: one object is called "a". As soon as "a" hits the collision checking object the variable will also be "a".   "a" is also full of properties which I can access by calling this my variable and then look for property. When my collision object is "b", I will get access to properties in object "b".
So the line:
If ( for collison checking object).positive:
Dict[variable]=(for collsion checking object).hitObject
variable=Scene.objects[str(variable)] #so is object is "a" i call a=Scene.objects["a"]
variable["property"]+=5

To change the property of whatever object comes on my collision checking object.
But now I have made another collision checking object with the same code but "variable" changed so it will manipulate every objects property which comes onto my second collision checking object.
So variable will change only what comes onto collision checking object1
And variable2 will change only what comes onto collision checking object2
But variable name turns out to be the same as variable2 because when duplicating the objects they will have the exact same name. And so on if I call to change property of variable2 object, variable objects property will change as well. And I don't want that to happen. So is there any kind of trick to have unique things so I can only change variable2 if I only want to change variable2?
All the other methods I've seen let you change property and based on that have a "unique" system. I know how to check for property in "variable2" object. But that isn't going to let me change other variables.
How can I solve this problem?

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


text:
Strange black textures in paint
So I'm fairly certain this is an easy fix, but I'm creating a bastard sword, and when I started the texturing phase, there are very strange black textures that I can't paint over.
If you want to  help me with this issue, I would appreciate it so much.
I am very new to Blender, so sorry if this is a waste of your time.
Oh, and by the way, I am talking about on the handle, not the crossguard.
And I have more images if you need more info.

Are any of your UVs overlapping?

I'm not too familiar with all the terms, but I have deleted all doubles if that's what your asking, thanks for the swift reply!

Please upload your .blend via http://blend-exchange.giantcowfilms.com

First I think you should look at the model's geometry. When I tried to use Remove Doubles, it deleted around 1500 vertices in each model. Also I can see you have some faces overlaying each others and there is a lot of unconnected geometry, so check / correct that too. Only then you will be able to do a proper texturing.

Is it because your Image Texture node isn't connected to the Diffuse node?

Sorry as I said before, I am very new at this. What part of the IT node and diffuse node should I connect?


text:
how to create and extrude a bmesh face
I would like to programmatically create and extrude polygons. I've found several examples of code (e.g. here), but none of them are currently working for me. As a simple example, I am trying to get things working first with a defined circular face and then extrude that face. Here is the code defining the circular bmesh:
import bpy, bmesh
from math import *

NUMVERTS = 1000
Dphi = 2*pi/NUMVERTS
# calculate x,y coordinate pairs
coords = [(cos(i*Dphi),sin(i*Dphi),0) for i in range(NUMVERTS)]

bm = bmesh.new()
for v in coords:
    bm.verts.new(v)
bm.faces.new(bm.verts)

bm.normal_update()

me = bpy.data.meshes.new("circle")
bm.to_mesh(me)
# add bmesh to scene
ob = bpy.data.objects.new("circle",me)
bpy.context.scene.objects.link(ob)
bpy.context.scene.update()

Which results in a 2D circle

I then want to extrude that face in z by some amount resulting in something like:

I would like to do everything in a python script without having to select anything in the GUI. Also, I'm using a circle as a placeholder example here -- I ultimately want to import much more complicated 2D (XY) polygons and extrude them in Z by some amount. Thanks!

Here is the extrusion part filled in:
import bpy, bmesh
from math import *
from mathutils import Vector

NUMVERTS = 1000
Dphi = 2*pi/NUMVERTS
# calculate x,y coordinate pairs
coords = [(cos(i*Dphi),sin(i*Dphi),0) for i in range(NUMVERTS)]

bm = bmesh.new()
for v in coords:
    bm.verts.new(v)

# think of this new vertices as bottom of the extruded shape
bottom = bm.faces.new(bm.verts)

# next we create top via extrude operator, note it doesn't move the new face
# we make our 1 face into a list so it can be accepted to geom
top = bmesh.ops.extrude_face_region(bm, geom=[bottom])

# here we move all vertices returned by the previous extrusion
# filter the "geom" list for vertices using list constructor
bmesh.ops.translate(bm, vec=Vector((0,0,1)), verts=[v for v in top["geom"] if isinstance(v,bmesh.types.BMVert)])

bm.normal_update()

me = bpy.data.meshes.new("circle")
bm.to_mesh(me)
# add bmesh to scene
ob = bpy.data.objects.new("circle",me)
bpy.context.scene.objects.link(ob)
bpy.context.scene.update()

The hard part is grasping the habit of having this dictionary return type from the operations. It's a dictionary containing definition for "geom" that contains a single list where all the verts, edges and faces are listed one after another. You are then supposed to make a list of the verts, edges or faces with python list construction where you check for the element type using isinstance(), depending on what you need for each operation.

Similarly to the link in your q, can use bmesh operators, in this case I've used solidify, Note you must set the normal before calling the operator to get the desired result.  Also note that face.normal = (0, 0, -1) (commented out) could (preferably?) be used in place of bm.normal_update().
import bpy, bmesh
from math import radians, sin, cos

NUMVERTS = 100
Dphi = radians(360) / NUMVERTS
# calculate x,y coordinate pairs
coords = [(cos(i * Dphi), sin(i * Dphi), 0) for i in range(NUMVERTS)]

bm = bmesh.new()
verts = [bm.verts.new(v) for v in coords]

face = bm.faces.new(verts)
bm.normal_update()
# or face.normal = (0, 0, -1)
bmesh.ops.solidify(bm, geom=[face], thickness=1.0)

me = bpy.data.meshes.new("circle")
bm.to_mesh(me)
# add bmesh to scene
ob = bpy.data.objects.new("circle",me)
bpy.context.scene.objects.link(ob)

However I've found if you are going to do for multiple faces then making the "wall" faces is significantly faster.  (that's my experience using similar to create 1000's of OSM buildings that are basically an extrusion of an ngon.)
import bpy, bmesh
from math import radians, cos, sin

from mathutils import Vector

NUMVERTS = 100
Dphi = radians(360) / NUMVERTS
height = 1.0
# calculate x,y coordinate pairs
coords = [(cos(i * Dphi), sin(i * Dphi), 0) for i in range(NUMVERTS)]

bm = bmesh.new()
verts = [bm.verts.new(v) for v in coords]
roofverts = [bm.verts.new(v.co + Vector((0, 0, height))) for v in verts]
# pop one on the end to make ring
roofverts.append(roofverts[0])
verts.append(verts[0])
for i in range(len(roofverts) - 1):
    wall = bm.faces.new([verts[i], roofverts[i], roofverts[i+1], verts[i+1]])
    #wall.material_index = matidx
# pop off to remove.
verts.pop()
roofverts.pop()
floor = bm.faces.new(verts)
top = bm.faces.new(roofverts)

me = bpy.data.meshes.new("circle")
bm.to_mesh(me)
# add bmesh to scene
ob = bpy.data.objects.new("circle",me)
bpy.context.scene.objects.link(ob)


text:
How to construct a stretchable array?
I'm new to Blender, and coming from an Acad background; so apologies if my terminology is a little off...
I'm trying to construct a 'stretchable array' comprising a module that can stretch and deform within defined limits and repeat itself such that it exactly fits a given length.
I'm attaching an image which hopefully illustrates what I'm talking about:

I'm happy to explore solutions which incorprate Sverchok, Tissue, etc.
Thanks

"I'm happy to explore solutions which incorprate Sverchok, Tissue, etc." This, in principle, is a Blender community.

@Lukasz-40sth Are Add-ons not allowed then?; I rather thought that was the point of Blender

They aren't but people here mainly use Blender and it may be hard to make you happy. And what do you mean? Do you want to do it with addons?

No. I'm just happy to explore a variety of solutions (and would be content with one)

Nice question. It's not clear in my mind what you are actually building: from a given a radius, how many elements do you expect to generate? a custom amount? or something correlated with the radius? Could you give us some examples of implementation?

@carlo I'm trying to construct a grille of indeterminate length. This design is a bit simplified from what I really have in mind, but the principle is similar.

Would an example be like a target store logo that which, when scaled outwards, would add more rings to the symbol?

@Nate_sycro if it allowed that all rings were the same width and the diameter could be any increment.

Yes like that. When it is scaled up the new rings would have the same band thickness, but a greater size.

@nate_sycro27 Robin's solution below is technically perfect; I'm just curious to see what other ideas might be out there. Also, in reality the shape is more complicated- but that's for another day.

His seems like the correct answer. I was considering adding another answer just for the sake of demonstrating this kind of effect on any object.

Here's a first shot using drivers, with a set-up to keep the expressions as simple as possible to begin with.
The X location of an Empty('End'), marks the length of the array. Moving 'End' in X changes a collection of driven values, and stretches the array. Everything is parented to another Empty at the origin, ('Start') so the rig works in Start's space, and can be moved about.
The arrayed object is a rectangle with 2 shape keys. The Basis key is set to width 0. The 'Width' key is set to width 1 at relative value 1, so the Value directly encodes the width.
The Count of the array is driven as follows:

The shape key of the rectangle is driven by the 'End' Empty, too:

... and the rectangle is rounded top and bottom by a driven Bevel modifier:

..with this result, so far:

I don't know whether this satisfies your requirements directly, but I'm sure it could be adjusted?

Hi, this looks very promising indeed.

i have to confess, not only can I not figure out how this works, I can't even figure out what object/parameter you're manipulating in the gif - I think I need a book... Ah, you're dragging the 'end' object; well, that's a start...

@Strawberry  Hmmm .. how can I help?  You could mute the modifiers, so you can see what they're doing... , or .. right-click the purple driven fields, and ' Open Driver Editor', adjust the expressions to see the effect? Get stuck, ask for a clarification, and I'll do my best. PS, you can delete the guide line, it's irrelevant, I was just using it to measure up.

The main manual section to read up is Drivers

Use self with drivers
Good example to show usage of use self with drivers. This way can put a property on an object (aka self) and drive other properties of that object with the property.

For example sake I'm using the width 2 as my basis width.
On the to be arrayed object added a custom property "length".  Note: The minimum is set to the size of the minimum units length in this case 2 to avoid zero division errors in driver expression. this could be handled for the single unit case
The origin of the object has been moved x-wards to zero such that object scales left to right.
Now it becomes a matter of driving the array count and x scale to fit our length following the rules outlined
The property we created, the array modifier count and scale all belong to the arrayed object so can take advantage of "use self" in drivers. This isn't default, so have to check the use self checkbox in driver editor to use
The variable  self is the driven object. For the case of the array modifier the modifier is the object being driven ie self is the array modifier object, BUT the ID object it belongs to is self.id_data. So in the expression this will be the arrayed object.  Bit confusing at first. If  say we wanted to bring the x offset of the modifier into our calculation it would be self.relative_offset_displace.x
Default array mod setup, with x relative offset 1.

Driving the array count.
How many 2 width base units fit our length.  The integer div operator // gives us this.

self.id_data["length"]  // 2

Driving the scale
Knowing the length and count above, how much bigger must a unit be than 2 to fit the length. Notice how for scale  use self["length"] // 2 as the scale property belongs to the object..

(self["length"] / (self["length"] // 2)) / 2

Nice explanation. It's considerably reduced my self-loathing.....

so easy, so useful, so great combination and great explanation.

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


text:
How to make Pivot rotate in the same direction as the object?
When I rotate an object, the pivot point doesn't follow the direction of the object, which makes editing really bad. The pivot point always stays on the same axes, no matter if you rotate the object. In cinema 4D this does not happen. How to do this in blander?

If you've rotated your cylinder in Object mode and want to see its orientation, open the Transform Orientations panel and switch from Global to Local:

If you've rotated the cylinder in Edit mode you need to realign the local axis correctly, see here.

Thanks very much!!!!!! Save me

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


text:
How do I Fix this Mesh? (Bad Shading)
I'm working on a hand and I tried connecting the thumb using Merge at Center [M], but I came across this mesh error and I'm unsure how to resolve this. I used Merge by distance but it's not working, I redid the whole hand however the same issue reoccured. How can this be solved.

We need informations on your geometry, please add close-up screenshots of the concerned geometry or upload your blend file https://blend-exchange.com/. Could be because of double vertices, bad normals, ...

It looks like you have flipped normals, try to select all in Edit mode and press Shift N

Thanks @moonboots, recalculating modules worked.

Hi. Please use a title that matches the content of the question. It should be descriptive but succinct, unique and identifying, summarizing the issue so that anyone searching for a similar problem is likely to find it. Remove anything superfluous, avoid using words like "this", "help with", "issue" or "question about", instead describe what "it" is. Remember, your title is the first thing potential visitors see, answers you get depend heavily on how insightful it is. See What is the problem of asking “How do I do this?"

As we can see if we display the face orientation you have flipped faces, you need to select all in Edit mode and press ShiftN to recalculate.


text:
Modeling Problem (Persian Helmet)
I want to model a Helmet, and I am attaching a photo so you can see what it looks like.

I wanted to know what method you would use to model if you were in my place?
And the second question, is it possible to model with geometry nodes? If yes, how I do this?
Thank you

Hi. "Modeling problem" does not say much about the content of the question. A title like that fits all modelling questions on BSE and is useless. You should use descriptive titles. "How to model helmet of Cyrus the Great?" or something like that would communicate more.

This task is definitely not something you should try to solve with Geometry Nodes.

@MartynasŽiemys You are right, thank you for your opinion

@quellenform Thanks buddy

@Maxendeer if you agree with Martynas Žiemys, why don't you change the title and improve your question for readers in the future?

@Blunder  it just got fixed

Begin with a UV Sphere that you cut off (make it match more with your reference image):

Extrude behind:

Extrude along normals to give it thickness:

Select all these edges and bevel:

Extrude these top faces along normals, first with a small Offset, then a second time with a larger:

Result with a Shade Smooth and a Subdivision Surface modifier:

Thank you very much for your great help buddy...
But I think you mean is start with cylinder, not uv sphere, right?

@Maxendeer no it's a UV Sphere, see my edit

Now I understand what you mean, thank you very much

I've noticed the first answer, just wanted to include a direction for the remaining parts.
Yes! A UV sphere is the best way to approach the big round part.
No Geometry Nodes are needed for this model.
Similar but slightly different approach is to use Inset on the face strips instead of Extrude
The front part can be modeled using Curve with Bevel Object, a Circle for the disk and star part and subdivided cubes for the two plates.

How to inset Face strips:
Select the odd columns of strips:

press "I" on your keyboard to invoke the Inset operator. Adjust the operator settings and add a Depth in negative direction:

Select the even columns of face strips:

Press Shift+R to repeat the last operation with the same settings:

Here is a screenshot of the Crown curve and the applied profile curve:

This is not a tutorial how to model a helmet but a guide on how to approach it.
Here is a .blend file with the model shown in the screenshots above.

Good addition! I would have used Inset as well. I would only guess for beginners it is showing way to few steps to get from the beginning to the finished result. But probably he could ask a new question when he's struggling with the parts after modelling the main sphere part.

Thanks @GordonBrinkmann. It is really hard to tell if the ridges are sharper or rounder so I went with the Inset option. There are many ways to skin this cat but I can understand the main struggle is how to start the big round shape (i.e  a good starting topology) even for an experienced modeler. Nowadays Geometry Nodes are overused for modeling when Blender can get things done quickly and painlessly with simpler tools. Maxendeer didn't mentioned he is a beginner, so I hope he understood the tips.

No, he didn't say he's a beginner, you're right. Maybe it's just because from my personal experience that in the beginning here I expected too much understanding/basic knowledge from askers which then turned out to be false. And since the goal of this site is to make questions and answers valuable for other people with similar problems in the future as well, I sometimes tend to be overexplaining things... well, as I also said, if he's struggling with something he can later ask more questions if necessary.

By the way, yes it is really hard to tell - after I saw the image I asked Google image search for "Persian helmet", but nothing that showed up looked anything like the reference... so I might be missing a special name for this variant. Anyway, I could not find out how it is supposed to be.

I've found this larger version of the reference image: https://dkstatics-public.digikala.com/digikala-products/849916.jpg

@RumenBelev Amazing result...Thank you so much for your help
I understood your explanation exactly, but it shows the final result very briefly in the gif photo
I have two problems now, one I can't make the shape used for the curve (bevel circle).
And secondly, can you tell me exactly how you made those bumps on the surface of helmet with inset or whatever !?

@RumenBelev Can I have your blender file please ?

Hi @Maxendeer I've updated the answer and included the .blend file for studying. Let us know how your project goes. Cheers.

Hi bro @RumenBelev I really don't know how to thank you...you did a great favor and help...I checked the file and saw the new photos you posted, now I got exactly what I wanted, your method was so great, thank you very much again.

Hi @Maxendeer, I am happy to help. Good luck and stay curious ;)


text:
Where did "Speed Factor" go? (Video Sequencer)

In version 4.0.2 there is no "Speed Factor" option. Where does this option live now?

The system has changed since Blender 4, you need to select the strip, enable Show Retiming Keys option and move the keys to speed up or slow down, it will be displayed in percentage. It looks a bit buggy for the moment, you may need to change the strip track to see the last key (??):

If you want to add a key go into Strip > Retiming > Add Retiming Key. And to set speed manually, Strip > Retiming > Set Speed:


text:
Which is the true size?
Why is it that when I create an object with numbers in transforms, everything is 2m?
I want to model based on real world dimensions and this confuses me.

You've scaled your object in Object mode, select them in Object mode and apply their scale (CtrlA > Apply Scale) and you'll see their real dimensions.


text:
after applying the normal map my character looks so weird
After applying the normal map this is how my character looks pls help. The file is available here

please tell a bit more, how does the high poly look like? maybe share your file (high poly + low poly + normal map picture)? https://blend-exchange.giantcowfilms.com/

What is the weird part of the "thing"? And the color from your normal map is a little bit strong and wide. You might want to adjust the strength value in the normal map node.

the weird part is the details does not show up (the texture) and it looks so shainy

@moonboots i cant upload the blend file or a jpg file i don't know why

you need to copy paste the url of this page in the field then click on upload

@moonboots the file is to big i can't upload it

@moonboots can you give me your email ill send it via https://wetransfer.com/

you can copy paste the link actually  ;)

@moonboots copy and paste what link>?

when you upload in wetransfer, just make yourself the receiver and it will give you a link when the upload is finished

@moonboots this is the download link https://we.tl/t-n2q0p71IQU

your character is a bit heavy for my computer and I'm not sure I'm familiar enough with 2.8, but if this is your normal map, why is it not mapped on a low-poly?


text:
Cutting Irregular Shape into an Irregular Cylinder (plane cockpit)
I've been battling with a problem for a few days, which i'm unable to resolve without creating awful topology/triangles etc. I've tried the Boolean route, but when it came to using subdiv surface / edge looping, the results were terrible due to all the triangles etc...
I've gone back to the drawing board to try and create a cleaner version, but i'm unable to figure out how to cut a cockpit (red line - see image) into the plane fuselage.  I tried subdividing into smaller squares then inset > pulling the cockpit quads down.  But this resulted in loads of triangular teeth around the edges.
Any suggestions on how to cut but retain good topology would be much appreciated!

Does this help ? https://blender.stackexchange.com/search?q=cockpit

So why don't you simply cut this part with a knife? Plus before adding edge loops you should make sure that the whole shape is good.

Some steps :

Thanks for this... I'm pretty new to blender so it took me a while to try and figure out how you jumped from your second screenie to the more complete third. Unsure if its correct https://imgur.com/a/aAoHzeH
My concern is that when i add a new loop cut (see image). It just ends at the hole and doesn't carry on the other side.  Doesn't this create topology issues further down the proces (UV Unwrap etc)?  How would i go about redirecting the cut around the hole?

yes except you should work with less edges around the cylinder, only add edges if necessary, some of your edges, the horizontal ones all around the cylinder, are useless, at least for the moment, you can test it, if you delete them and it doesn't change the whole shape it meant they were not useful

I think you may have missed the edits on my previous message :) sorry.  So I dont need any new horizontal edge loop to be linked both sides of the hole? I will also cull come of my lines.  Thanks!

I think you can dissolve at least one out of 2 of these horizontal edges: https://zupimages.net/up/20/21/ypi5.jpg   the simpler your shape is the better it will be, then only add edges if necessary. Try first to model a vary basic shape with as few edges as possible, with all your plane elements: cockpit, wings, etc... work from the biggest to the smallest

Understood.  I appreciate the time you've spent on this - there's a lot to take in when beginning 3D! Just one more question before I mark as answered.  How did you create this red line https://imgur.com/a/Lzy1nKF?  I extruded > right click > scale and dragged in.  But there must be a cleaner method?

The red line is actually my original knife cut, but the display is a bit misleading, please look at my answer's edit, I explain step by step

Great, thanks Moonboots.  This is my attempt using my limited skills.  Ive simplified the general mesh a bit and added loops to the edges of the hole to sharpen them.  I also clicked the 'on cage' button inside the subsurf modifier.  Doesnt look too bad :) https://imgur.com/a/7089rzl

I only clicked on the cage option for fun and for aesthetic  ;)  don't use it when you model your object. Ok good luck!

+1 for a very pretty aeroplane. Nice to see you back :)

thanks, nice to see you too   ;)


text:
How could I hear a sound from one VSE in another
Start up a new blend file.

Go into VSE
Add audio
Add another new scene (in the same file)
Go into VSE of this new scene.
Add a scene strip of the first scene

But you can't hear the audio from that VSE Scene Strip.
How do I fix that?

If I change Scene > Input from Camera to Sequencer, it plays the audio, but it does not show the camera view.
If I add the same scene strip and I set Input > Camera, the sequence doesn't work either.

I'm not that good in Blender, I just started this year.
My Blender Version is. 3.2.0
My PC specs are
Lenovo Chromebook 300E 4GB RAM 32GB

you can ask as many questions as you want - that's totally fine. But...you should provide all (!) necessary informations, which you didn't. So please provide the blend file so we can check it out. Thx. Also please tell us your blender version.

These are known bugs; please follow the issue below if you want to keep track. https://projects.blender.org/blender/blender/issues/69444 I also tried @vklidu's suggestion about the Speaker objects, but discovered another nested scene problem, https://projects.blender.org/blender/blender/issues/129126

In the scenario where ...

Scene A containes audio strip in VSE and
Scene B with Scene A strip placed in this VSE.

Hmm, same for me ... if Scene A is Input > Sequencer it plays (and shows correctly what is in VSE, that cant be current 3D Viewport), scene strip duplication make strip silent ...
... it sounds to me like a bug (or could be called a current limitation by devs) ... so the only way that came to my mind (that worked for me) is to add Speaker object into Scene A into 3D Viewport :)
Note: similar (not the same, but probably related to each other) issue on bug tracker.

If you are experiencing audio lag go to Timeline Editor > Playback > Sync Audio https://imgur.com/WYFhY8e

For video lag search for cache (proxy works only foe sequence or movie not for scene strip).

Any problem to test it out? BTW comment section is not allowed for chatting. What about delete ours previous comments ... Thanks


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How can I add motion blur to a pre-rendered (existing) video clip?
I have some videos recorded at 48fps (which is to say, I'm not exporting objects modeled in Blender, so general motion blur tutorials I've found don't apply) and want to use the "inbetween" frames to help generate final videos at 24fps with some level of motion blur (as if they had been recorded with a slower shutter)
I've found other people trying to do similar things, but their questions are either so old that the answers are full of dead links (which may not reflect the best way to do it in recent versions of VSE/Nodes--which by the way, I have very very little experience with Blender's effects nodes/Cycles so if those are the solution as I'm guessing they are I'd appreciate a breakdown of the relevant specifics if possible) or have something else going on (like masking) that makes the best approach different from my needs. As far as I can tell, my case is very simple, which I guess makes it a bit unusual? Just want to output a video at half the framerate but with motion blur.

Honestly, I would not do this in Blender, I would do it in DaVinci Resolve... like almost all of my video editing.

Likewise. Using da Vinci resolve is the answer

It's hilarious that I was just about to ask a similar question and this was the first question on the query list.
I would like to know how to store a series of pngs, an animation, with ALL of their inherent data. So maybe later I can add motion blur, glare, or what not. What format would store this data, just in case you wanted to use it later?

PNGs can't store passes, you would have to store one image sequence per pass. Also PNGs are incredibly slow to read and write. PNG is made primarily for internet display, not for production. These reasons are why EXR multilayer is used in the industry.

There are many tutorials and guides online that show how to save render passes, with or without EXR Multilayer. Search for those, and post here on BSE if you encounter issues @JBRiley

Video Sequence Editor
One old school fake if you really want motion blur for existing footage in Blender ... probably you are lucky one if your original footage is 48 fps and you want to result in 24 fps, so you have a chance to control a bit better blur effect.

Duplicate the strip a few times, each time with one frame offset on Timeline, blend mode Alpha Over ... in this example I used 3 duplications so the Opacity 1 has to be divided by 3, so Opacity  0,333 ...

Notes:

For Blender 2.79 there are some addons to speed it up the workflow ... MBlur (works for video not image sequence) or similar function integrated in Kinoraw Tools as Eco Effect (works for image sequence when in MetaStrip).

In general this technique mimics reality, where camera catches fast moving object partly contaminated by background.Specific pixel is exposed to light without and with moving object. Fading effect is just a result of different amount of exposure of moving object at specific place in space (more far less time spent at that place). So this technique does the same, you are just limited by existing in between frames to get enough smooth transition. That is why I wrote lucky you if you can use 48 fps and divide result to 24 fps that gives you one frame in-between.

The same you can do in compositor ...

Or you can try this preblured composite and use high-pass to isolate like a vector of motion and use it as a mask for mix original with pre-blurred version.

For artistic strike blur (that is just behind moving object) use Lighten blend mode and Opacity divided by half of previous layer opacity.

@LOLock it seems we edited my post at the same time (and it ruins our both edits) so I deleted your unfinished part. Please I appreciate your input, but it would be nicer if you start it by comment. I saw this technique used at colorful fight video so I can't agree it works only for BW graphics ... about colors. Yes, there're some imperfections (I mentioned), but it can be my wrong interpretation or can be fixed by RGB Curves modifier. Here left with blur / right your original https://imgur.com/mXWNHM2 or here https://imgur.com/16qGzYk

Should have commented first indeed, sorry about that.

I've seen this technique mainly used on isolated parts, like a layer on 2d animation or in comp, not the whole final render nor live action footage. When the whole render is already done and is not simple shapes BW, I highly suspect it won't look right "as is" and will require adjusting, maybe the color, or the blur quantity itself, using masks to isolate things in the frame and tweak/remove the blur, ... And on fast camera/object movements might just not work at all. Not saying it can't be done! Just some caveats to keep in mind.

@LOLock I found original fight video, but the quality is to low to see effect, so just some screen of something else. I edit the blend mode that doesn't shift colours. I think all downsides are already visible, even that the result is not so bad for what it is. The movement is fast enough to see effect from 48 to 24fps. Your example is another extreme and if you have a chance to render regular m-blur and play there would not be probably such drastic difference for viewer.

AFAIK The only motion blur Blender can do is either at render time using the engine's motion blur, or in compositing using the Vector and Z passes generated at render time and the Vector Blur Node in Compositing.
But you can't apply the render engine's motion blur nor generate passes after rendering, and you can't do anything on recorded footage.
Sources:

Motion Blur — Blender Manual
Vector (Motion) Blur Node — Blender Manual
Passes — Blender Manual

If you have a render's Vector and Z passes, all you have to do is pass it in Blender's compositor with this setup:

But if you don't have these passes, Blender has no way to analyze your frames and "invent" motion blur out of it. Other softwares have tools for that, like DaVinci Resolve, but that's out of topic on this website.


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Strange blocks appearing in my render
Created a tree using the sapling add-on, and when I render it, strange blocks start appearing all over the image.
The leaves are simple rectangles, with a Velvet material applied to them.

Increase transparent light bounces?

Do you have any other addons enabled which may cause this?

Nice render btw


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When I render my model in blender the only thing that appears is the blue color i have for the backround
I've been trying to fix this for ages and can't seem to find a solution. I'm rendering with cycles. I've tried messing with the layers and different render engines and even tried finding a solution based on other questions but no luck.
Here is the blend file

Without further information any answers would probably be guesses. Screenshots are very helpful and uploading your .blends to http://blend-exchange.giantcowfilms.com/ is invauleable.

There is an Object in your scene which is set to Wireframe Display mode in the viewport, but when rendered it is being shaded solid. It encompasses all your objects, so basically it hides everything. The object in question is called CloudBounds, and is highlighted in this screenshot:

The camera however is clearly outside of this box:

Probably you have tried to generate clouds using an Add-on which targets Blender Internal render engine? It would explain why there are no nodes on the cycles shader (it still has the button labeled use nodes):

Anyways, if you move that object to a separate layer which is not set as a RenderLayer, or simply hide or delete it, the scene renders again:

Thank you so much, this problem was really confusing me. I appreciate the help.

Everything renders properly now:)

Possibly you have placed the camera at a positon, where it does not point at any geometry. Blender always renders through the active camera.
Hit NUMPAD-0 when your mouse cursor is over the 3D-viewport to look through your active camera.

I checked the camera and everything checks out


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Beveling along a straight path — why does size change?
I'm trying to sweep a profile curve along a path curve, where the path curve (the one to which I'll apply the bevel) is a simple set of straight lines and right angles.
When I set the path curve's Bevel Object to the profile curve, I get roughly the desired result, except that the size of the profile curve gets bigger as it approaches the ends of the path. Why is that, and what do I do about it? (I tried setting a straight taper curve, but that doesn't help.)
Here's a simple blend file showing the problem:

Thanks!

Usually if I am working with a Curve, I am able to select a control point and use Alt-S to Shrink/Fatten the curve at that point. Yours seems to be locked somehow.

the profile doesn't get "bigger as it approaches the ends" it actually gets narrower in tight corners. It's a limitation of the current bevel system, see the comment above for more details.

See what happens when you turn on 2D in the Curve.

@ Craig D Jones ... yeah I was wondering why his curve couldn't do the Alt-S modification on the ends but I made a copy of the original curve and then it worked! Strange.

@cegaton Edited as requested. Thanks all for the quick responses.

Hi there, I am involved in addressing this issue in Blender. This is still in development but closing in on a solution and that'd be great if you could provide some feedback here: https://devtalk.blender.org/t/curve-to-mesh-node-even-thickness-feedback-thread/27271  - Thanks in advance!


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Applying fog glow to textures

The image above is one of my previous renders and the one below is my recent render. As you can see, I applied a texture to each of the objects in the model, however the in the previous render the fog glow around the texture is superior to that of the image below. I am unable to recreate the same effect in the latest render and all attempt to do so result in the diffuse material also being affected by the Glare Filter. Can anyone help me out here?
This is my setup:

This is one of my references:

You need to put the object(s) you are applying the Glare Node to on a separate Render Layer. Then apply the Glare node to that layer.

@Dontwalk yes, already did that, but as you can see, it's affecting the diffuse materials on that layer too

Make sure you don't confuse render layers with scene layers, if you have two render layers then it is impossible that your compositing affects the other one if you set the effects before mixing the passes. If you wish to use compositing on a particular object or material within a single layer you will have to use object/material ID.

@Yvain They are on separate render layers (check my files)


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How to make a stylized low-poly tube tree?
So, I want to make a tree something like this:

However, I don't want the fur/hair on it. I want the tree to be made
using tubes and as seen in the image the same tube(s) in the stump should branch out and form the branches.
Also, each branch should reduce in thickness as it extends to it's end.
I'm making this for a game asset,hence I need it as low-poly as possible.

Use the skin modifier

@DuarteFarrajotaRamos Tried doing that..doesn't work the way I want. how do i get it to twist around itself at specific points?

Not sure if skin supports tilting, otherwise adjust it after converting to mesh

@DuarteFarrajotaRamos could you show me how?

Try this video: Make a rope in Blender

That changes the mesh in the render..not physically, I wont be able to take it into a game engine.

@DuarteFarrajotaRamos I tried your method, but couldn't get it to work

I've been testing and the Skin modifier does not support tilting. So to get the twisted surface either use a bezier curve object instead, if you don't need a continuous surface, or deform it afterwards using Proportional Edit, or a Lattice or Simple Deform or any other method to your liking

@DuarteFarrajotaRamos sounds promising, could you show it to me in detail?


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Not able to animate after frame 30
I have set up a simple rig with IKs and am not able to keyframe the bones properly.
Although I select all bones before keyframing it, it seems that I'm not able to animate any bone after frame 30. Is this a bug?
I currently use Blender 2.78 a.
This is my .blend file:

You need to unpin the animation in the NLA editor as shown below and the animation will be there after frame 30 normally

You have converted your action to an NLA strip. Outside the range of the NLA strip the action is no longer shown.

Go to the NLA editor. Select the strip. Press X to delete it.
Go to the Dopesheet. Set it to Action Editor mode and choose the action you were working on (which we just deleted in the NLA editor). Now you can work on the full action again.

You probably pressed this button, then continued to edit your action.

how do i set it to action editor?

@Tejas - select it in the mode menu in the dopesheet header.


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How to model a jagged cave?
How I recreate/model a cave that looks exactly like this (?):

I have tried using particle systems but it ended up looking ugly as the particles overlapped way too much and could not be given an individual, unique offset as seen in the image.Am I missing something regarding the particles?
Also, I'm open to any other suggestion to go about this.

You could achieve an approximate result through a Remesh modifier.

Add cylinder object, rotate and scale it to make it elongated and subdivide accordingly. Erase the end faces.

On top of it add a Subdivision Surface modifier set to Simple, then a Displace modifier.
Set the displace amount to a high value like 1 (depending on the size of your object) and add a new texture.
Switch texture type to Musgrave or similar and increase the size so the deformation forms big lumps (as opposed to small frequency noise).

Now add a Remesh modifier to the object set to Blocks. Adjust the Octree Depth to a high enough value to generate desired sized blocks.
You can now add another Subdivision Surface modifier set to Simple on top of it followed by another Displace with a new Musgrave texture.
Seth both the Displace Distance value and Texture Size to small values to generate small distortions. Adjust accordingly

your solution gives me a part fo my answer and the solution under yours gives me the rest, now I'm conflicted whom to attribute it to XD

Don't worry about it, if both answers helped you then just upvote them. Marking as accepted is optional

Start with a circle, make faces. Extrude and then S to make the section closest to you wider.
Delete faces from both ends. Then add round loop cuts (Ctrl+R) to the inside of the object. Next, grab faces and extrude inward inside the object.
Start with the bigger pieces extruding a few faces at a time. Use R and S on the extruded faces to add complexity.
Add vertices and other loop cuts until you get the desired results.

This answer would be a lot easier to follow if you added a few example screenshots

How do I upload images?

While editing a question there is an insert image button at the toolbar. If you press it a dialog with builtin upload options will pop up. You may not have enough reputation to upload a lot of pictures.

Nice job, keep it up


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How to use Blender's dynamic sky add-on?
How do I use the dynamic sky add-on to create a:
1 daytime sky with no cloud?
2 night-time sky with stars?
3 sunset sky with clouds?
I'll be using the cycles render engine.
Also are there any other things I need to know about the add-on?
Problems Faced
I don't know how the "sphere" that controls the light direction works

I don't know how to make it look realistic.
I don't know how to control the cloud level and horizon level.
So, I made this using your technique:

Now, I'm unable to add volumetric lighting, such that a light beam is clearly visible from the lighthouse. Also, if I were to change the camera angle, there should be God Rays visible from behind the floating rocks. And light shafts exiting the door too.
Now, the lighthouse has a spot lamp with a 20-degree cone with a brightness of 500 and the lights in the house have a brightness of 10 / 20, all light source emission shaders are connected to a blackbody output with a temperature of 1800K.

Could you tell what kind of difficulties you faced while trying to create those skies (apart from the stars, that I don't think are currently included in the add on)?

Is this a tutorial request or did you run into some problem?

@Jerryno yes and yes, it's like this I don't know how to use this addon plus    I don't know how to use that "sphere" thingy that controls the direction of the sunlight.

@Carlo I've made the necessary question edits

What do you mean by this: "I control the cloud level and horizon level."?

@LukeD whoops, that's a typo, correcting it now

Ok, so basically you want to control how high/low horizon should be? If yes I'll need to investigate it further. I'm making an answer for the rest.

First go here: http://www.dragoneex.com/downloads/dynamic-skyadd-on and look at "Instruction" section. This is self-explanatory and will help with further tasks.
Controlling sun/moon
These sphere you are referring to is nothing more then Vector > Normal Node. There is a little info in docs about it so I'll quickly show you how to control sun with it in most understandable way.

Simply, go to the Top View and this is the way you can relate to the sphere shading. If sphere is lit from the left, mesh will be lit the same way. If light will be visible at the center of the sphere, mesh will be lit from the top.
Daytime sky without clouds
This one is the easiest one. You only need to change Cloud Opacity to 0. These will hide our clouds. You can further adjust colors, brightness, etc.
Used colors

Sky - #b0ecff
Horizon - #fbeaea
Cloud - #ffffff
Sun - #bcbcbc

Sunset sky with clouds
In this example colors are crucial. Darker sky, orange horizon, warmer sun light, lower Brightness. Also you will need to tweak Clouds Opacity and Density as needed. Don't forget to place sun near Horizon using tip from first paragraph.
Used colors

Sky - #385179
Horizon - #fb8648
Cloud - #ffb9a8
Sun - #bc9481

Night-time sky with stars
This is where the fun begins and in this paragraph you will learn how to push this add-on to the limits. It's not the easiest way but it will give you total control over it. One thing I can't solve is moon opacity over stars. Maybe someone could help here.
Used colors

Sky - #151f2e
Horizon - #191825
Cloud - #ffffff
Sun - #7688a0

First as before adjust overall mood and colors. Brightness down, colors darker, cool sun/moon light. And after it...

...go to the Node Editor and switch to World. This is an overview of what part of those noodles control what we can see.

Stars

To make stars from clouds change bottom Noise Texture to Voronoi Texture, set Scale in Mapping node to 1 (X, Y, Z) and adjust Color Ramp (from Voronoi) to have "sharp" stars. Upper Noise Texture is controlled by Clouds Density value in add-on tab. This is basically "mask" for the stars/clouds. If set to 1 it will create "gaps" between them.
Moon/Sun

In this part you can control how big sun/moon will be, and how big will be its halo. Nothing really to explain here. Slide Color Ramp values and change upper Multiply Node value.
Horizon level

Another fairly easy setup, left values from Color Ramps are controlling horizon/sky/clouds height. Right (middle) ones are controlling sharpness.
Sun color
You can change Sun color in MixRGB node showed in screenshot. You can also change blending mode to Linear Light to have stronger colors.

Final thoughts
As far as last method isn't convenient one and feels more like "hacky" way to do this I think it could give you pretty much anything you need from this add-on. My advice would be - play with values, nodes, colors in Node Editor to find new ways to use it.
In a matter of making it realistic. Well. Overall lightning is ok. I don't know if it's physically correct but it's really good. One thing that's not realistic are clouds and stars and there is probably nothing you can do about it in this add-on. Of course you can create amazing procedural cloud setup and use it in a place of two Noise Textures but still they will be just 2D representation of clouds without Volume Scattering and such.
If something is not clear in my answer, please point it in the comments. It was pretty long one and something could be missed.

Ok, simple question: How do I control the overall star concentration?

Also, could provide me the color hexcodes from each of the scenes?

@Tejas I've added HEX colors, but you can easily read those values using Color Picker in software like Krita, Gimp, Photoshop or even Paint. You can control stars "patches" by Noise Texture, I've described it as "mask".

Cool! Thanks ... One question though, is it possible to add volumetric lighting ? (As in God Rays or light beams) while using this method? If so, then how would I do that?

I'll show you a raw render of my scene, can't upload it unfortunately, as it is huge

done, the scene is complex though and I do appreciate the help. :)

Let us continue this discussion in chat.

Hey, is there any way to change the color of the sun/moon?

@Tejas check edit.

It seems like Cloud Density doesn't affect anything in v2.91.2.  I would expect there to be more or less clouds in the rendering, but I always seem to have partly cloudy.  Also odd that I can type in a value >1 into this field.


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How can I model a bottle with triangular base and circular top? (Nail Polish Bottle)
Does anyone have any advice on how I can model this specific nail varnish bottle for a client? The base of the bottle is a sort of triangle and becomes a rounded and circular at the lid? any advice on how I can create a shape that's triangular at the bottom and circular at the top would be great!

The others have done it.. but don't forget, if you use a Solidify  modifier to make the glass, you can aim the modifier at a vertex group, and vary the thickness of the glass by weights in that group.

Hi thanks for this, would you mind explaining further how I can go about doing this? Thanks

I've been trying it.. it does help, i think, but, because of  overlaps in this shape, there's still some hand modelling to do after applying Solidify, so it's not magic. I'll have to write it up. Set up a Vertex Group: 'Thickness' .. aim a  Solidify modifier at it.. adjust weights to vary the thickness of your glass, (solidifying inwards). Experiment with a simple subdivided plane to begin with. You'll get the idea.

Create a 3 vertex circle, bevel the vertices:

Create additional vertices on the edges, scale a bit:

Extrude up and right click > LoopTools > Circle:

Create horizontal edge loops in order to follow the bottle profile:

Give it a smooth shading and a Subdivision Surface modifier:

thanks for the reply, I've followed the steps but when I apply smooth shading, I get these two sharp edges that run down the side of the bottle? is there a fix for this or a reason this might be happening?

could you please share your file (copy paste the url it will give once uploaded)? https://pasteall.org/blend/

@Joe Chapman, maybe the bevel you've made is too tight (your base triangle is to sharp), that would explain why the edges are too sharp?

You're right, this really helped ! thank you

You might be looking into Mesh > Transform > To Sphere option, shortcut ShiftAltS:

Are you able to easily rotate the top back so the three sides are straight again after the sphere is made via this method, or is the distortion shown pseudo permanent?

@TCooper That seems to be caused by the circle having roughly the same average diameter as the triangle did previously, so it bulges outward where the flat sides used to be while it goes in where the corners were.  You'd obviously have to shrink this down afterwards to match the taper of the bottle.

@TCooper perhaps you want Loop Tools > circle instead (with default "Regular" enabled). I would add that to the answer, but I don't want to interfere with this answer being my worst answer yet, and yet on its way to become my highest voted answer.

Here is a step by step guide to get the general shape of this, since it's triangular the difficulty of creating this shape is greatly increased. But you can get on the right track by following along.
Step 1: create a cylinder object, and set the vertices to 3.

This will give us the base of our object
Step 2: Bevel and subdivide, make sure to have a reference image handy in your scene to figure out how much you need to do this.

Step 3: Now delete the top half of your object, select a loop left at the top, duplicate it, and align it with the circular area near the top of the bottle. Then with the loop tools addon enabled, right click, and turn it circular.

Step 4: Now select the triangular section top loop again, and the circular one, and go back to the loop tools menu, but this time select bridge.

Step 5: Add some edge loops in there, scale them and proportionally edit everything until it looks right, add in the lid, add a glass-like principled bsdf shader, extrude an interior, and bam you've got yourself a sally hansen bottle.

Sorry if this isn't terribly in depth, I am assuming that you have some experience with Blender just don't know how to go about making this specific shape. If you'd like I can edit it to be a bit more detailed.

I have some experience but not with modelling real objects, would you be able to go into more detail? Thanks so much

No problem, do you need more details on the buttons I pressed? How to get the shaders working? Or anything else specific?

step 2 and step 3 in particular, buttons pressed would be helpful :)

For step 2, select all the faces of the object, and press (ctrl+b) to bevel. Then in face selection (3) mode press (a) and select all faces, then subdivide them by right clicking. This gives some extra geometry for later. Now go into side view, press (ctrl+z) to enter transparency mode, press b, click and drag over the top faces. X to delete them. (option+select/mouse) to pick the loop of the top part. Shift+D to duplicate. G+Z move it up into place. Transform to sphere or loop tool circle. Then bridge.

Thank you so much for this, this really helped a lot !

No problem, glad to be of help


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Cutting Square Hole In a Cylinder
I'm trying to model a spot light and couldn't figure out how to cut a perfect hole on the body without having weird artefacts on the mesh. I have been trying to model this thing for months and still stuck in the same point without any progress. hope some one can help.
[1

It's hard to tell from that screenshot, but you certainly seem to have n-gons there (faces with more than 4 vertices). Possibly you have additional vertices at some of those apparent corners of the cutout. You could try Remove Doubles but don't use a very high threshold or you'll mangle your other close-together vertices.

https://blender.stackexchange.com/questions/81596/how-can-i-make-a-rounded-indentation-on-a-cylinder/81605#81605 https://blender.stackexchange.com/questions/5856/cutting-a-circular-hole-in-a-hollow-cylinder-without-distorting-the-cylinder https://blender.stackexchange.com/questions/15633/cutting-rectangular-hole-in-a-cylinder-with-subsurf-modifier

Here are the steps I used. Disclaimer: I am only a couple of months into Blender with very little prior experience so if I use the wrong setting please point it out so I can learn as well.
I put auto smooth on and added an array, mirror modifier and lattice plus a simple metallic material at the end. Can't yet do materials, lighting etc. Still learning - thanks
Happy to share the blend file but no idea how to add it to the thread

Thanks. Very helpful.

Here is a way to do it, but if you want to avoid any pinching it needs more geometry than on your screenshot. Once done, you can delete the useless geometry, i.e. vertical edge loops on the rest of the cylinder:

..beat me to exactly the same topo  :)

I may be wrong but it looks like it's the only way to make a square hole in a sphere or cylinder


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How to UV Unwrap properly? (Boat)
I'm fairly new to Blender, in fact, I've been '3d modelling' in Blender for no longer than 10 days.
While my 3d modelling skills are slowly getting sharpened I'm completely clueless on how I would unwrap this model I'm currently working on.
This is an asset for a game, by the way is far from be finished, but I wanted to test the components scales, so I though, let me chuck some materials and see how it look in the game with proper lighting and stuff... I couldn't be more disappointed with the results.
Here's my model in Blender:

And here's how it looks when I import it to my game using smart UV project or lightmap pack to generate the texture.

Like I said, I'm fairly new to Blender and based on the researches I did, it seems that I should be using seams although I also noticed that there are several different strategies, and I have no idea where to start from...
So if somebody could provide some sort of guidance, or point me into a tutorial, or something that would help me to solve this problem I would very much appreciate.
PS: I can link my 3d model if necessary.
Thanks!

yes I think using seams would be the best strategy for your object, as you could place your UVmap on a wood plank texture

Yes, but the question is how do I do that? Is there any tutorial or technique explained?

For this kind of project you need to create some seams before the unwrap, then load a wood image texture that is tileable so that it can repeat without visible seam, in the UV Editor place the UV islands correctly on this image, load the image into an Image Texture node, plug this node into the Principled BSDF node, and to give a bit 3D bumps to your texture, plug a black and white version of your texture into a Bump node that you plug into the Normal socket of the Principled (or ideally, create a b&w displacement map from your wood texture with a software like CrazyBump). Of course the texture is improvable with a bit of glossiness etc...


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How to do difference boolean between two objects in Blender?
Hello i have 4 cylinders in a "cube" and i want to extrude cube with them.
I want to delete the cylinders and leave holes in cube.
(cylinders in my case are holes for screws).
I tried to use boolean but not work or maybe i can't able to use it.

I hope you can help me...
Here file:

edit after use boolean

the top faces of you cylinders overlay the faces of your cube, which is not good for boolean, you could select all your cylinder, move them up a bit, join them together with a ctrl J, and now boolean the cube

but if i join them then with what i should to do bollean ? if join i have only one object... i don't understand

only join the 4 cylinders, not the cylinders with the cube  ;)

i tried joining only 4 cylinders but when i do bollean not work... maybe is important for you know that i created cylinder with add "circle", then ctrl+f, and extrude it

that's weird because it works on my computer... Have you moved them up a bit so that the faces don't overlay? Also maybe select all the vertices and recalculate the normals of the cylinders in Edit mode, before the boolean, although I didn't have to do it... And keep in mind that once you've applied the boolean, the original objects that are used to boolean stays in place, you need to move them to see the holes

yes but not work because the hole should be on the whole thickness :( ... instead there is the hole only on one face .... now I put two photos

oh ok I see so there might be a topology problem somewhere, wait...

ok, it's because some vertical faces of your cylinders are sticking to some of the vertical faces of your cube, if you move them a little bit away it will work. It's still a problem of overlaying faces as you can see.

i must move what ? after boolean ? sorry...

before boolean, I'm going to answer with pictures, please wait 3mn  ;)

Your problem is that the cylinders you use to boolean your cube have faces overlaying the cube faces, and the boolean doesn't work in these conditions. So here is what you need to do:

Select your 4 cylinders and join them with ctrlJ to make it simpler (one boolean instead of 4).
As you can see the top and bottom faces of the cylinders overlay with the horizontal faces of the cubes. To prevent this, just scale the cylinder object on the Z axis.
Now there is another overlaying, between some vertical faces of the cylinders and some vertical faces of the cube. So you need to select your cylinders object, go in Edit mode, then move each cylinder a bit away from their position on the X axis.
Now you can apply the Boolean, as you can see it works.

oh yes now works and now i know use better even boolean..... thanks a lot @moonboots :) :)


text:
How do we produce LESS smoke?
LOVE smoke sims. But sometimes, it's too darn much smoke - here's a train scaled to travel 60 MPH. I'm just fussing around with a BIG domain and 120 resolution divisions LOOKS like a small enough voxel (?) for that smokestack which is holding a vertex group - the top rim. That size though! It's gushing giant clouds instead of smokestack sized pillows as implied by the sample voxel or smoke pixel.

I may have edited a pasteall link into the question correctly per your request.

Issue
Domain is too long. If you set Divisions to 120 means longest side of domain is divided by this value. For domain of this lenght it means "big" voxel cell.
You can try by your self, go to edit mode, with Ctrl+R close to center of long edge (when yellow loop appear) type 120, so domain become divided by this number. From there you can see that emitter is inside one voxel and rising smoke expand into two others.

Solution
You would have to increase divisions, but for this type of domain totally unreasonable. Depend on animation type you can try something else.

Make domain shorter and enable Dissolve, so smoke disappear in specified amount of frames. From your file I see you already use it, so parent domain to your train and enable also Adaptive domain.

Or try particles instead https://www.youtube.com/watch?v=tL0G5oOjdtk
For stady camera, like viewing incoming train with long smoke trail, you can try to use more domains https://vimeo.com/246353861

Once I tried shape keys for incoming car. Long domain with same divisions for far shot, but when car become closer I animated domain lenght into shorter. So for close up view domain became with enough division in camera view. I even didnt expect it can work, so there was offcourse issue, in a moment of resize domain smoke like exploded :) https://vimeo.com/177600070

Bingo. Despite enabling Adaptive, also had to center the Origin to Geometry for better behavior. Never would have thought to parent a domain to anything; I just kept making it big.


text:
How to get/copy pixel coordinates or rgb values from 2d image, in compositor editor?
Many times, i need to get and copy pixel coordinates (as well as rgb values) from the composite 2D image in the backdrop or image viewer. i can see it from the image editor by clicking in the image preview, but as soon as i release the mouse, these data are not shown anymore.

Is there any way to get these data and copy them?
Need something fast to process (CTRL+C ideally) from the gui.
If not available in the last 3.3x blender release, maybe an addon is already exists, none as i know.
thanks

I don't have an answer, just to keep it visible you can Search for "image.sample" ... also for pixel coordinate you can switch to Mask (type view) by click you can position 2D cursor, under Properties (N) > View > 2D Cursor you can see x/y coordinates ... but yes - someone who is pythons could to know how to let those infos print into Console editor or so ... BTW to pick a colour - you can easily by pressing E above colour field in any move above image and click.

that´s right, the color picker in the toolbar (T) serves this purpose of copying color value. could be an option to add a tool to copy coordinates too


text:
Armature doesn't want to spin around intended origin
The origin is at the feet squarely below the torso. If I sit the character down in for example a spinning chair and try to spin him, he becomes offset from it because his torso is behind the spinning axis of the chair but his spinning axis is still beneath his torso despite posing his legs. This is more of a question of practice than anything. Surely the origin shouldn't be in front of a model because that would compromise his ability to rotate while standing up but I cant think of what to do other than temporarily shift the origin in edit mode which seems like more trouble than it might be worth.

You don't have to shift origin in edit mode. Just parent armature to chair (if you want animate spinning from chair origin). For parented armature doesn't matter where origin is placed.
Like here - Armature and Cone are parented to Empty with animated rotation.
You can also parent armature directly to Cone, I did it just for a more freedom.

But seems to me more efficient use Bone Constraint modifier (for hip bone) > Copy Rotation, Target: Empty or Chair (animated), Mix: Add .

When I would code this for a game, I would do it like this:

Apply the sit down animation and wait for it to finish.
Make the Character a child of the spinning chair seat.
Rotate the seat of the spinning chair.

Im not sure how to do this within a blender animation but I hope this approach might be useful for finding a solution.


text:
How can you find out the position and rotation of an object in relationship to its parent?
When you add an Object Info node for an object that is the child of another object the location and rotation outputs are its world coordinate position and rotation. I would like to find out the location and rotation of an object in its local coordinates. In other words, as if the parent object was at the center of the world and not rotated at all. Any help would be appreciated!

Using Relative Location/Rotation from Object Info node seems to be value you are looking for ...

Cube at World origin is Parent, Cube.001 is a Child ... When you move Child object values at Spread Sheet are changing. When you move by Parent object - values are kept.
In other words - Location values of Object Info node set to Relative gives you child location like parent object is at child's 0/0/0 local world origin.

Also known as Local transforms

Thanks @validu. But that is not quite what I would like to find out. For example in this image you can see that if I create a new object and put your node setup in it (bottom image), the information I get is the child cube's world position and rotation. https://1drv.ms/u/s!AiE01B39ctoQhOpA9Wdx5R7yhrP7Uw?e=ZSfVdU. I have tried just subtracting the position and rotation of the parent from the child. But apparently its more complicated than that. I have been struggling with this for a while.

I think I didn't get your point. Probably add some sketch (drawing) explaining what position (or distance) are you aiming to calculate. Like now it does what I understood you asked for. When I add Plane with GN, the Cube.001 (child) position is calculated from Plane position = means Plane is taken into account as World Origin.


text:
Subdivision surface modifier adds crease to head

How do I fix this issue and have a nice smooth head?
file: https://drive.google.com/file/d/1iihG60xaokuOx3EAqDik2LGjbg8KCVxv/view?usp=sharing

You seem to have double vertices on the same spot.
To merge all vertices on the same spot you have to select all vertices and press  M and select Merge > By Distance


text:
How to create a fluorescent fluid material?
Does anyone know how to create a material similar to the fluorescent green fluid found in this image?

Credit: Anton Lavrushkin

IMHO it's yellow, not green.

I apologize, I have a mild color blindness.

Here's one way to do it:

and what it looks like if it's the only source

To get precisely the look you want, play with the strength of the emission node and the Blend value of the Layer Weight node.
Basically this makes the material transparent in the center and gradually more emissive as you approach the edges, as viewed from the camera.
It's common to put a black and white color ramp between the Layer Weight and the Mix shader to give even more control over the mixing effect.

Since the reference image is glowing in places construction around the tube ... Marty's material can be enhanced by AO (Ambient Occlusion) factor to fake this part of light effect.


text:
Compositor - File Output - PNG compression ratio issue
I use the compositor to save my renders into files with the "File Output" node. I want to have the smallest file size while preserving all information. I use PNG file format with the highest compression ratio, i.e. 100%.
My problem comes from the output file size. It seems that the compression ratio in the "File Output" node is not the same as the one when manually saving the image with the Image Editor (Image Editor > Image > Save As...).
Here are the figures with the default Cube rendering.
File Output node in compositor :

PNG 0% : 8.3 MB
PNG 15% : 1.0 MB
PNG 100% : 610 KB

Manual saving via Image Editor :

PNG 0% : 8.3 MB
PNG 15% : 75 KB
PNG 100% : 38 KB

So for the same level of compression, I have different image size.
Maybe I miss something. Can anyone help ?
Thanks.
Blender version : official 2.82 on Linux.
Screenshot of my compositor node settings :

File browser with file sizes :

All files look the same (resized below) :

I can't reproduce this issue on my system, both have manually saved images and the ones from the file output node have the same size. The compression ratios you're reporting from the Image Editor don't seem right, even for when your only save a black and white version.

Thank you for responding. If I understand, you say that file sizes I report from Image Editor saving are not correct. I've just check and I find the same results. I edit my post to add screenshots of my file browser showing those files and their size. And I've checked with GIMP, there is no difference between files (that's expected).

The difference comes from the dithering. This post-process is not applied on the viewer node but is applied on the render. You can find more info on dithering : https://docs.blender.org/manual/en/dev/render/output/settings.html#dithering

Dithering is a technique for blurring pixels to prevent banding that
  is seen in areas of gradients, where stair-stepping appears between
  colors

Dithering adds noise. It explains why file sizes are not the same (noise is harder to compress).
Below, the first image does not have dithering and the second one does have dithering (maybe you need to zoom in to see the difference).

To get back to my initial question, the image saved with the File Output node via the Compositor has dithering and the image saved from the Viewer Node via the Image Editor does not have dithering.
I get the info from developers on ticket I opened :
https://developer.blender.org/T74071


text:
Trying to merge vertices on all individual meshes in a scene
I'm starting scripting and would like to merge the vertices of all the individual mesh objects in my blender scene. So far I've got this script. It runs but doesn't process the meshes. It doesn't select any verts to apply the remove doubles command to. It always says: "Info: Removed 0 vertice(s)". Note:the variable x is to stop it after first 10 meshes (3000 meshes in scene).
import bpy
x = 0
for obj in bpy.context.scene.objects:
    if obj.type == 'MESH':
        #print("mesh")
        print(obj.name)
        bpy.ops.object.editmode_toggle()
        bpy.ops.mesh.select_mode(use_extend=False, use_expand=False, type='VERT')
        bpy.ops.mesh.select_all(action='SELECT')
        bpy.ops.mesh.remove_doubles()
        bpy.ops.object.editmode_toggle()
        print("-done")
        x=x+1
    if x > 10:
        break
print ("finished2.2")

import bpy

ojs = bpy.data.objects

# make sure you are in object mode first
bpy.ops.object.select_all(action='DESELECT') # deselect all object

x = 1
for oj in ojs:
    if oj.type == 'MESH':
        print(f"MESH object: {oj.name}")
        oj.select_set(True)

    if x == 11:
        # need a active object to join
        bpy.context.view_layer.objects.active = oj
        break
    x += 1

bpy.ops.object.join()
bpy.ops.object.mode_set(mode = 'EDIT')
bpy.ops.mesh.select_mode(use_extend=False, use_expand=False, type='VERT')
bpy.ops.mesh.select_all(action='SELECT')

# Adjust threshold to suitable value if vertices are too far
bpy.ops.mesh.remove_doubles(threshold=0.0001, use_unselected=False, use_sharp_edge_from_normals=False)

The key is that you just select the object in data, but it don't mean the object is selected in the viewport.So, just add 1 line to active it works.
import bpy
x = 0
for obj in bpy.context.scene.objects:
    if obj.type == 'MESH':
        #what you should add
        bpy.context.view_layer.objects.active=obj
        #print("mesh")
        print(obj.name)
        bpy.ops.object.editmode_toggle()
        bpy.ops.mesh.select_mode(use_extend=False, use_expand=False, type='VERT')
        bpy.ops.mesh.select_all(action='SELECT')
        bpy.ops.mesh.remove_doubles()
        bpy.ops.object.editmode_toggle()
        print("-done")
        x=x+1
    if x > 10:
        break
print ("finished2.2")


text:
Arrow animation in 2D
I think I have understood the basic principles of animating an arrow traveling along a curve. My problem is that my arrow becomes twisted as it travels along the curve. What is it that I do wrong? Does it somehow has to do do with the fact that I'm working in 2D

Try changing the Twisting setting from the default Minimum to Z-UP in the Curve settings.

https://blender.stackexchange.com/help/someone-answers

If you want your arrow to grow along the curve:

Give your arrow an Array modifier, choose Fit Type > Fixed Count, and End Cap > arrow like you did.
Give your arrow a second modifier, a Curve modifier, and choose the Path as the Object.
Now increase the amount of Count of your Array, the arrow grows along the curve.
You can now insert keyframes so that at frame 1 of the timeline there is only one duplication and at frame X there is as many duplications as you want.
Note that, anyway, the arrow will be messed up at the U turn of the curve, as your arrow is not subdivide, is big, and the curve is sharp. If you don't want the front of your arrow to be deformed it should be a separate object and it should move along the curve (with the method explained below).

If you want your arrow to move along the curve:
You gave your arrow a Curve modifier while, for your purpose (follow a curve without deformation) you should have given it a Follow Path constraint.
Right now it is behaving like it is supposed to. You've given your arrow a Curve modifier, which means that it follows the curve you've chosen as Object and it deforms along this curve. As your arrow is big and doesn't have a high poly mesh, the deformation is a bit messy. Even with a high poly mesh it won't give anything great.
If you want your arrow to follow the curve without any deformation, you need to give it a Follow Path constraint:

Remove the Follow Path you gave to the curve (it is useless, the curve won't follow any path).
Delete the Curve modifier you gave to the arrow.
Delete the previous Follow Path you gave to the arrow and give it a new one.
In this modifier click on the Animate Path button, and enable the Follow Curve option. As Blender doesn't know how you want to orientate the arrow, try different Forward (X is the good one).
Now the arrow follows the curve without any deformation.

Now if you want to control the speed of the arrow along the curve:

Select the curve, open the Graph Editor window, on the left panel (Path > NurbsPath.001), unfold NurbsPath.001 and click on Evaluation Time. Open the right panel with N and click on the Modifiers tab. Delete the Generator modifier (X). You've delete the animation you've automatically generated when you created the Follow Path constraint you gave to the arrow, and the arrow doesn't move any more. You have to reprogram the animation.
In the Properties panel > Data > Path Animation, choose the amount of Frames you want. 100 by default is ok. It means you choose to segment your curve 100 times. The Evaluation Time will determine at what segment of your curve your arrow will be at the time you want. For example place your timeline cursor (green bar) at 1 and create a keyframe (i) on the Evaluation Time > 0.00. Now move your timeline cursor to 20, go back to the Evaluation Time, choose 50, and create a keyframe. Now from frame 1 to frame 20 the arrow moves from the beginning of the curve to its middle.
If you want the animation to be linear and not smooth as it is by default, in the Graph Editor, press t and choose Linear.

Ok. But I didn' add a "curve modfier"? I added an array modifier. Could you a little bit more explicit, I'm pretty new to modifiers and constraints.

you added a Curve modifier below the Array, and you don't need the Array either, Array is made to repeat an object, it's not your purpose here

Well I want the arrow to grow along the curve.

Also, If I take away the modifier, I loose the the actual arrow (there are two objects in layer 11: a "base" and the actual arrow). Please bear with me!

you should edit your question and explain precisely what you want with some drawings, so that we give you the best way to do it

and you don't have to get rid of your Array if you absolutely want to keep it, what I say is that you must use the Follow Path constraint instead of the Curve modifier

I create an object out of a plane consisting of two separate pieces: a base and an arrow (with a space between)
Then I separate the base from the arrow, creating two separate arrows
I highlight the base and go to origin to geometry
I move the 2 objects to layer 11
In layer 11 I copy the base and place it in layer 1 and chose “selection to grid”
I also add a u-shaped curve path to work as the path for my objects
As I was following a tutorial, this I where I added a array modifier. I’m trying to no avail to add a follow path constrain.

PS. I did try to add an array modifier and then follow path constrain but I get lost among the settings

could you please share your file? https://blend-exchange.giantcowfilms.com/

I was just about to to do it. Thanks for your patience. Here it is:

Ok. Fine. Just one thing: As I wrote before, I wanted it to grow, meaning that expands from the base til it reaches its end point.

aaah ok so wait a bit I'll edit my answer. But note that that was note your first question

Thanks a lot Mr Moonboots. As you suggested, the solution is partly to to subdivide the meshes, tho make the arrow thinner in proportion to the curve or vice verse. Strictly speaking the initial tutorial was right, although it failed to mention subdivision of the meshes. Anyway, thanks for all your patience and help.

it really depends if you want the front of the arrow to bend... if you don't want, then it should be a completely separate object and use a follow path constraint while the tail should use a curve modifier


text:
Rigging 2D elephant trunk corrupts the mesh
I’m struggling hard with a rig for an elephant trunk. I want the trunk to rise up in the air and trumpet. I tried to increase and decrease the vertices, I’ve tried bendy bones and assigning the bones manually via the vertice groups. Which ever approach I choose, it seems that when I exceed a certain angle in bending, the mesh gets corrupted. How should I proceed?

Image of trunk. Slightly modified by reader.  Note the armature could be placed closer to mesh before armature binding.

Your question is not clear.  Please make it clear. Please show your work as a screen capture.  Please do this always in the future.  Please do this even if you include the blend file.  Many times the screen image is enough to solve the issue and some people do not want to open a blend file.

Please see this tutorial video https://www.youtube.com/watch?v=GvG39bGEsKI. You may also choose to see many or all tutorials from this same video provider.

If you want 2D animation then flat mesh is acceptable. If you want 3D animation then a cylinder shape is better.

https://blender.stackexchange.com/help/someone-answers

A tube with an armature as its spine which used Bind with automatic weights.  Image above.

Back up your current work with file save
Create a new quick cylinder with loopcuts say 20. Scale to your tastes and elephant trunk shape.  Keep the cylinder in straight line.
Create a new armature with 20 bones. Keep the original straight shape.
The more loop cuts in the cylinder mesh, with more bones in the armature, will allow a smoother movement.
Move the armature to be located in the cylinder. Make sure trunk is reasonable tight fit to armature. A tube with no fancy shape is fine because the tube can be changed later after binding to armature.  The learning experience will be better.
The above steps will take 8 minutes with practice
Ensure the placement by examining from different angles
Bind Trunk to Armature with automatic weights
You may choose reserve frame 1 for the straight armature shape and insert keyframes for all bones.
Move to some other frame say frame 8
Test the binding by rotating bones of the armature in pose mode. Insert keyframes.
You can create a shape key for the cylinder mesh if you like
You can shape the trunk with more lifelike shape
These above steps are an improvement. If you wind the bones in too tight of a spiral you might not like the results. Bad results such as this can be true of any simple model for Blender Beginners.
Delete all previous work when satisfied.  Your previous work has some new user problems which can be discarded.  A fresh start can be good.
Be aware of the Spline IK constraint which allows a smooth curve to control the armature and may save time once its mastered

Thanks, but my animation is 2D. Also, the minecraft tutorial you supplied is not really applicable for me, since I want my rig to be soft and bendable whereas in Minecraft everything is typically squarish.

The idea of starting out with a straight trunk is probably the way to go.  Thanks buddy!

I would rather vote up or down rather than a thanks.

https://blender.stackexchange.com/help/someone-answers


text:
Recreate Solidify Thickness Clamp in Geometry Nodes?
I am trying to build the Solidify modifier in geometry nodes. Generally this is simple as there are many ways to offset a copy of the geometry. And we have Extrude to create the Rim. However, I am stuck on the Thickness Clamp option, which is the primary thing I need.
The docs give this description, but its not specific enough to build from:

I've also looked into the source code. The relevant functions seem to be in source\blender\modifiers\intern\MOD_solidify_extrude.cc. This snippet seems to be it, and starts at line 869 (but there are other snippets that start with if (do_clamp) so I'm not entirely sure.) I'm not an advanced enough coder to figure out exactly what's going on here.
    if (do_clamp) {
  const float clamp_fac = 1 + (do_angle_clamp ? fabsf(smd->offset_fac) : 0);
  const float offset = fabsf(smd->offset) * smd->offset_clamp * clamp_fac;
  if (offset > FLT_EPSILON) {
    float *vert_lens_sq = static_cast<float *>(
        MEM_malloc_arrayN(verts_num, sizeof(float), "vert_lens_sq"));
    const float offset_sq = offset * offset;
    copy_vn_fl(vert_lens_sq, int(verts_num), FLT_MAX);
    for (i = 0; i < edges_num; i++) {
      const float ed_len = len_squared_v3v3(vert_positions[edges[i][0]],
                                            vert_positions[edges[i][1]]);
      vert_lens_sq[edges[i][0]] = min_ff(vert_lens_sq[edges[i][0]], ed_len);
      vert_lens_sq[edges[i][1]] = min_ff(vert_lens_sq[edges[i][1]], ed_len);
    }
    if (do_angle_clamp) {
      for (i = 0; i < verts_num; i++) {
        float cos_ang = cosf(vert_angs[i] * 0.5f);
        if (cos_ang > 0) {
          float max_off = sqrtf(vert_lens_sq[i]) * 0.5f / cos_ang;
          if (max_off < offset * 0.5f) {
            vert_angles[i] *= max_off / offset * 2;
          }
        }
      }
      MEM_freeN(vert_angs);
    }
    else {
      for (i = 0; i < verts_num; i++) {
        if (vert_lens_sq[i] < offset_sq) {
          float scalar = sqrtf(vert_lens_sq[i]) / offset;
          vert_angles[i] *= scalar;
        }
      }
    }
    MEM_freeN(vert_lens_sq);
  }
}

Has anybody built this already, or can explain what's happening?

That code snippet really solved this headache. You get the distance between every vertex (=edge length). That is essentially it. You then use that to influence the scaling along normals you do with your solidify modifier.
As my mesh had different mesh densities, and thus lower lengths in said areas, I remapped, and removed the lower ranges of mesh density/higher values.

Regarding the angle clamp, I didn't need that so I havent tried to figure it out. But feeding code into chat gpt and making it explain to you whats happening should get you further than you were.


text:
How to apply gradient to small part of UV Map?
I want to apply a gradient, using the fill tool in texture paint, and apply it to only a small part of my UV map. Any ways I can do that? As you can see, when I apply the gradient, it gets applied  across the whole UV map. Instead I would like it applied to only a small part of the UV map. I could UV map each part separately, but then I wouldn't be able to apply one texture to the whole mesh.

Thanks,
Best regards,
IdealistDeveloper

First idea is to use the 3D View painting to do this by using Face Selection Masking to only apply the gradient to the area selected.

Thank you so much!


text:
Transform cylinder to flat plane - cylinder maze map
I have object like this:

I want to cut it in half and flatten it to something like plane.
In other words I want create flat map of this maze - all simple ways are welcome.
file:

plane > cylinder would  be easier...

This might work..
It's a script which gets as close as I can to inverting the Simple Deform > Bend modifier.
It's not very general, and makes some assumptions:

The Cylindrical version is circular in XY, up in Z.
That it has a cut gap at min Y around X=0. If there are coincident vertices where the gap is, in the illustration, the result can be usable, but untidy (the script doesn't know the difference between 0 and 360 degrees).
The object has all its transforms applied, and its origin is at its XY center.

Select the object in Object Mode, and run this:
import bpy
from math import atan2, sqrt

cyl = bpy.context.object
if cyl:
    flt = cyl.copy()
    me = flt.data.copy()
    flt.data = me
    bpy.context.collection.objects.link(flt)

min_r = float("inf")

for v in me.vertices:
    x, y, z = v.co
    r = v.co.xy.length
    theta = atan2(x, y)
    v.co = theta, r, z
    min_r = min(r, min_r)

for v in me.vertices:
    v.co.x *= min_r
    v.co.y -= min_r

flt.location.y += min_r

Which should produce a straightened version (green, derived from blue), scaled and located, ready to be bent back by Simple Deform > Bend.

The Bend modifier uses the bounding box of the straightened object. Because of the gap, the required bend is not quite 360 degrees. In the example .blend, the match is reached at about 356 degrees.

Lurking Pythonistas / bpyists are welcome to improve or correct the style of this script.

Oh, that animation is very neat :).

@JachymMichal ..the question of how to unbend something so it can be bent back again using the modifier has come up a few times..

@Markus von Broady ... just seen this post referenced..  belated thanks for the tidy-ups!

Bmesh script

Splitting script to bisect first, copy, and then "unfurl" copy and join as shapes
Similarly to a cylindrical UV projection can "unwrap" a cylinder from cylindrical coordinates to flat.
(Just seen RobinBetts excellent answer, doing much the same.)
Some Pre Pro on mesh
Firstly going to be a lot easier to set origin to geometry (bounds)  Can also be done via bounding box

which in this case puts it in pipe centre.  The xy coordinate vector of any vertex gives its distance from the pipe axis.

Have also removed the coplanar faces of the "nut end". (Would need to be poked to axis line to unfurl nicely)
The script
Bisects the pipe with a cutting plane.
Have arbitrarily chosen the ZY plane to chop the pipe where locally Y > 0 (the top looking down)
Select a vertex as unfurl radius
Run in edit mode. Select a vertex you wish to be the xy radius to unfurl radius r to XY plane.  The height will be the xy radius take r, the Y value the old z value and the x the longitude angle (remember arc length = angle in radians.)

Script. Edit mode select vertex. then run script. (Alters the mesh, so as always backup first / run on copy etc)
import bpy
import bmesh
from mathutils import Vector
from math import copysign, pi

context = bpy.context

ob = context.object
me = ob.data

bm = bmesh.from_edit_mesh(me)
#bm.from_mesh(me)

v_r = bm.select_history.active
r = v_r.co.xy.length

assert(isinstance(v_r, bmesh.types.BMVert), "Select a Vert")
cut = bmesh.ops.bisect_plane(
        bm,
        geom=[f for f in bm.faces if all(v.co.y > 0 for v in f.verts)] + [e for e in bm.edges if all(v.co.y > 0 for v in e.verts)] + [v for v in bm.verts if v.co > 0],
        plane_no=(1, 0, 0),
        )["geom_cut"]

for g in cut:
    g.select = True

bmesh.ops.split_edges(
        bm,
        edges=[e for e in cut if isinstance(e, bmesh.types.BMEdge)],
        verts=[v for v in cut if isinstance(v, bmesh.types.BMVert)],
        use_verts=True
        )

# now "unfurl"

up = Vector((0, -1))
for v in bm.verts:
    co = v.co.copy()
    angle = -up.angle_signed(v.co.xy)
    if 1 + up.dot(v.co.xy.normalized()) < 1e-4:
        # meridian
        fv = sum((f.calc_center_median().x
            for f in v.link_faces)
                 ) / len(v.link_faces)
        v.select_set(True)
        angle = copysign(angle, fv)
    v.co.y = co.z
    v.co.z = co.xy.length - r
    v.co.x = angle * r

bmesh.update_edit_mesh(me)

I've just figured out how you're  dealing with 0. Very nice.

Here is a solution that seems to work:

Select your cylinder, go in Edit mode, create or select the frontal vertical edge and rip it with V or cut with the knife (K), with the through option enable (Z).

Create a plane, subdivide it vertically.

Give you plane a Simple Deform modifier / Bend mode, choose an Angle Deform of 360° so that it contains the cylinder. If the plane doesn't bend correctly try to apply its rotation.

Give your cylinder a Surface Deform modifier with the plane as Target, click on Bind.

Disable the plane's Simple Deform visibility, the cylinder should flatten.

Apply the cylinder's Surface Deform modifier, you now have a flat mesh, you may need to give some small corrections.

For my mesh this method not work or I do something wrong. Can you try this method on this mesh: https://www.sendgb.com/qZ1UCADib30?

yes your original mesh is a bit messy, I'm not sure it's easy to fix


text:
Background scene model or image as plane?
I have the 3D model and can render with white background.
However i would like to make the model look like it is in a promo shoot like the attached images, would these be modelled scenes or images as plains or what?
Would there be any good tutorials on this subject that somebody could recommend

just use an HDRI background, make a plane under the bike with shadow catcher and render in cycles

I have tried a few 4k models and it looks really fake so i am a bit stuck TBH

Yes an HDRI image as background and maybe create the grass with a particle system?


text:
How to make a twisted wrapper/cloth
How do I make a twisted wrapper like the following?

I've tried to twist a plane / a cone, but many faces just go though others.

Apologies if this is obvious or not relevant, but if it's for a piece of candy, the twists on each end go in opposite directions so it opens when you pull. Yum.

Leander has given a nice solution with Cloth physics, here are solutions with modeling only, you can give them Cloth physics at the end if you want to make it more realistic.

A bezier curve to which you give a bevel object and a taper object. If you select the bezier vertices you can twist them with CtrlT, AltT to reset, N panel > Transform > Tilt to type a value.

A tube mesh to which you give a Mesh Deform modifier. Create a cube that encages it, choose it as the Mesh Deform object, create a basic shapekey, then a new one that you twist the way you want (no risk of face intersections with this method).

If you give it a Cloth physic afterwards (here Leather).

If you want to use the cloth simulation, you have to assign both ends to bones.

You also have to create the Pinning group for the cloth simulation. At the pinched end, I used only a few vertices for pinning, otherwise the circular structure will remain rigid.

Animate the right hand bone twisting.

This is the result with a cloth simulation.

I thought of something like that but I didn't know it would give such a good result. It would be nice to have your cloth settings

Added some settings.