Beginner Python Exercise in Blender: Make a cube from a list of vertices
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- čas přidán 26. 07. 2024
- This is a video exercise for Blender Python beginners.
We will write a Python script that creates a Cube from a list of vertices and faces.
Final code:
gist.github.com/CGArtPython/4...
00:00 - Intro
00:30 - Setup Workspace
00:58 - Adding Lists
01:28 - Create mesh data
03:02 - Add a vert
03:27 - Create an object
05:18 - Add to the Scene Collection
06:09 - Removing orphan data
06:35 - Adding verts to form a face
07:13 - Show vert indices
08:23 - Define a face
09:17 - Check face orientation
09:30 - Define remaining verts
10:03 - Define remaining faces
11:18 - Inspecting a face
12:52 - What is a Python script?
13:53 - Exercise #1
14:34 - Exercise #2
15:08 - Outro
Intro Music
Fiery Trails - Silent Partner
Outro Music
Geographer - Easy Shake
#blender #python #scripting
You are the most useful resource I have found on python/blender scripts. Thanks you!
Thank you for your kind words!
love this.
I made the exercise 1 in a different way than yours.
I just add variables on edges. 😀
Thanks again Victor! you are the best!🤘
That is awesome!! 😄
I'll make sure to watch it this evening. As always... thanks for your efforts :)
Thanks for your support Brett! :)
Thank you! That was a great tutorial!
The big advantage of it, that you are able to solve the task. That’s greate to have a little success, after you got the exercises done. Those little portions combined with success in my opinion, are a key to learn further. This is a kind of lessons I needed for python.
Like and Abo and big thanks 🙏🍀
Woohoo! 😆
You're very welcome! 💖
thank you so much for this .. I was trying exactly this a few months ago, but wanted to figure it out on my own .. and was even less used to blender than I am today .. now I can finally improvise on this! :)
That is awesome!
Really happy this was useful to you.
Super well taught! Thank you for sharing your knowledge!!!
Thanks Philippe!
bro i just started python in blender with you and your descriptions are amazing , thank you very much!
Glad you like them! ❤️🔥
Note to run scripts less than possible: for faces choose verts *CONTRAclockwise* to set normals outward (blue color), and clockwise to set normals inward (red color).
Note 2: with indices view enable, be sure that you in vertices selection mode (Edit Mode -> 1), otherwise, indices will be shown to edges (2), faces (3) - I checked, if it created the edges automatically, and forget to set back to verts selection, and spent time to figure out what the problem was... now, you know how to solve this issue.
Thanks for sharing your notes!
Thanks for the video. I just recently ventured into using python with blender and I'm excited about it. Real quick though, has anyone ever told you you looked like Peter Dinklage? :D
Glad you found the channel! 😀
You are the first one to tell me that I look like Peter Dinklage 🙃
This was really useful. Thank you!
Glad it was helpful!
amazing video, keep it up!!
Thank you! Will do! 😊
thank you!!!!!!!
You're welcome!
You made bpybb - just use them, no need to repeat "old truths" every video. Great job man!
Thanks Aleksander!
At some point, I’ll start doing that for some videos.
Just trying to keep the code setup easy so more people would follow along. Especially for beginner videos.
Installing bpybb would introduce friction and some people would fall off.
With copy & paste, the only function is opening the link in the browser ;)
But thank you for encouraging this
@@CGPython Thank you for keeping it to the foundational rudiments, honestly! When I get to a place where I understand what bpybb is, I'm sure I will appreciate that, too, in same way I now appreciate tuples.
@@jmfs3497 I'm glad to hear that you think this is important.
Thanks for sharing your thoughts
The very last clip was the most interesting, which looked like a randomly positioned objects floating.. Go over the code for that.
hello Victor, thanks for the tutorials. At the end I wanted to recalculate the normals so that they point outwards, but I did not succeed.
Hey Artur,
I'm glad you liked it!
If you want to recalculate the normals you can add this code to the end of your script
```
# set the mesh object as the active object
bpy.context.view_layer.objects.active = mesh_obj
# switch to Edit Mode
bpy.ops.object.mode_set(mode='EDIT')
# recalculate the normals
bpy.ops.mesh.normals_make_consistent(inside=False)
# switch to Object Mode
bpy.ops.object.mode_set(mode='OBJECT')
```
The catch here is that you need to set the mesh object as the active object and then enter Edit mode.
Here is the full example
gist.github.com/CGArtPython/1f294c42d72583e4c766ed7ed7454608
@@CGPython It works now! So you can't just use anything from the Log of Operations as a command :D
Hi, this video came up on the search of my problem and it was a huge help.
I need to automat the creation of some specific modular gameobjects. Creating those within Unity would be no problem. However I do want to create an atlas of modular elements within blender and I am new to this topic of programming within blender. Creating those intended base modules within the gameengine and trying to export those (however?) for specific variations into blender does sound more complicated. So I am trying to use blender directly.
Following those steps I managed to create some prototypes like intended. However the upcoming problem is the following:
While defining the faces I would also like to specify the UV-positions of each vertex of the current face.
I was hoping to find something like:
UV_POSITION_OF_VERTICES_OF_FACES=[[(0,1),(0.2,1),(0.2,0),(0,0)],[...],[...],[...]] ?
mesh_data.from_pydata(verts, edges, faces, UV_POSITIONS_OF_VERTICES_OF_FACES) ?
Does such a similar function with those intended parameters exist or something similar?
I was searching for an answer, but I assume I do not even know how to search in this category correctly for my problem. All I got were examples concerning unwrapping or answers with loops, where I could not find a single assignation with a 2d-vector position.
Thanks for this tutorial
Hey,
Glad you liked the tutorial!
That is an interesting problem.
UVs are represented as loops under the hood of Blender
I think this should help you
b3d.interplanety.org/en/how-to-create-a-new-mesh-uv-with-the-blender-python-api/
@@CGPython Thanks for the example. This example helped me to solve this problem.
Thank you very much! Are you providing online lessons? Thanks!
Not yet!
why does the order of the indexes change the face orientation? how do you know which order to go?
This is due to the "winding order." The winding order is a concept in 3D graphics that determines where the front side of a face is.
here is a good definition from LearnWebGL: "The order of a triangle's vertices are used to determine which side of a triangle is the front side. If you are looking at a triangle and the order of the vertices is counter-clockwise, then, by convention, you are looking at the front of the triangle. The order of a triangle's vertices is called the winding order. "
Just make sure that the vert indices are in a counter-clockwise order to get the result you want.
Привет. Не подскажите, куда копать, чтобы добавить элементы интерактивности в скрипты. Как определить выделенные вершины или ребра, как отследить положение курсора (мыши) и в реальном времени строить объекты кликами. Пришел из C# и многие вещи в Python кажутся дикими :). Имеются ли какие-то код-конвеншн по написанию скриптов, чтобы приучить себя сразу? Спасибо и удачи с каналом.
Thanks, friend!
To make a script interactive, you would need to start learning about Blender add-ons.
Blender has a lot of template add-ons that you can use as examples. These templates were written by the Blender devs and serve as examples of how you should write add-ons.
You can find these examples and other scripts that ship with Blender in the install dir of Blender under \scripts, for example `3.4\scripts`.
I have a video about going over one of the templates here:
czcams.com/video/x3QRp2k013k/video.html
I would recommend installing VSCode (if you haven't already) and setting up pylint and auto-formatting with black.readthedocs.io/
Also set up this extension marketplace.visualstudio.com/items?itemName=JacquesLucke.blender-development
I plan to make videos about all of this.
For tracking the cursor position, I would start looking at the operator_modal_draw.py template example.
Is there an easy-ish solution to place text at each one of the indices?
(Specifically text that I can manipulate)
Thank you for your question! 😀
Try this
gist.github.com/CGArtPython/0a116fd19d66ecf2bd3ad42c18dc1bd8
To stop drawing the text run the script again with `run = False`
@@CGPython Thank you for the example!
this clears up a few things for me.
I didn't realize blender had another import option specifically for fonts. (was trying to do everything from the bpy API).
very helpful thanks! But let me ask you Is there a way to declare the variable of vertices (more than 68) so that some function can update the coordinates?
For a simple list, you can use verts=list(range(208))
For verts=[(1,0,1),(1,2,3)....] how ?
Finnaly i used verts[] ... verts.append((0,0,0))
Hello,
I'm glad it was helpful!
Where will you get the coordinates from, and what will define the faces or edges?
@@CGPython coordinates calculated by a function
#faces defined by this function
def appendfaces():
i=0
ln=int(len(verts)*0.5)
for x in range(1,ln):
faces.append(i+1,i,i+2,i+3)
i+=2
faceappend(i+1,i,0,1)
ln=int(len(verts))
t=tuple( i for i in range(ln) if i%2==1 )
faces.append(t)
s=tuple( i for i in range(ln-2,-1,-2) )
faces.append(s)
#but one more function is nesesary to appendfaces can work
def vertsappend(xx,yy,zz,height):
verts.append((xx,yy,zz))
verts.append((xx,yy,zz+height))
# i give you an exemple for simple cube
def simplecube():
vertsappend(0,0,0,1)
vertsappend(1,0,0,1)
vertsappend(1,1,0,1)
vertsappend(0,1,0,1)
from your video i noticed that number 1 vertice is above 0 vertice not next to 0
why? ...
becauce the face become 0,1,3,2 .... 2,3,5,4 .....
the last two faces are 1,3,5,7 ... and ..... 6,4,2,0
so you can make every profile you can imagine
@@spirosmarinis2510 > from your video i noticed that number 1 vertice is above 0 vertice not next to 0 why?
vertex 1 is actually next to vertex 0 (on the Y)
(-1.0, -1.0, -1.0),
(-1.0, 1.0, -1.0),
Sorry, still not sure where you are getting the 68 vertices. In your example, you only have 8?
@@CGPython
i am new in python and blender
i am sending you the final text i hope it will work in my pc is ok
these are the 68 vertices
import bpy
import math
def aktinia(mires):
return mires * (math.atan(1)/45)
def iparxi_object(obj_name):
rs=False
try:
oj=bpy.data.objects[obj_name]
rs=True
except:
oj=None
print("there is not object such name " + obj_name )
finally:
return rs
class Tapa_L:
def __init__(self,onoma,tx,ty,tz,paxos,batos,ypsos,r):
self.verts=[]
self.edges=[]
self.faces=[]
self.name=onoma
self.new_obj= True
self.tx= tx
self.ty=ty
self.tz=tz
self.paxos=paxos
self.batos=batos
self.ypsos=ypsos
self.r=r
self.ob=None
self.vr=None
self.j=0
def set_ob(self):
if iparxi_object(self.name):
self.ob= bpy.data.objects[self.name]
self.new_obj=False
self.redraw_tapa()
else:
self.new_obj=True
self.draw_tapa()
def draw_tapa(self):
self.verts.clear()
self.tapa_v()
mesh_data=bpy.data.meshes.new(self.name)
self.faces_table()
mesh_data.from_pydata(self.verts,self.edges,self.faces)
self.ob=bpy.data.objects.new(self.name,mesh_data)
bpy.context.collection.objects.link(self.ob)
self.ob.location[0]=self.tx
self.ob.location[1]=self.ty
self.ob.location[2]=self.tz
def redraw_tapa(self):
self.vr=self.ob.data.vertices
self.tapa_v()
self.ob.location[0]=self.tx
self.ob.location[1]=self.ty
self.ob.location[2]=self.tz
def tapa_v(self):
self.j=0
dx=list(range(6))
self.pinakasshmeioon(self.r,dx)
self.sira(0,0,0,self.paxos,self.batos,self.r)
self.sira(0,0,self.ypsos-self.r,self.paxos,self.batos,self.r)
idr=5
teshz= self.ypsos-self.r
for x in range(1,6):
r1 = dx[x]
dk=self.r-r1
self.sira(0+dk,0,teshz + dx[idr],self.paxos-dk,self.batos-dk,r1)
idr-=1
dk=self.r
self.siraΤelos(0+dk,0,0+self.ypsos,self.paxos-dk,self.batos-dk, self.r)
def faces_table(self):
self.faces.clear()
i=0
for x in range(1,7):
for y in range(1,9):
self.faces.append((i,i+1,i+10,i+9))
i+=1
i+=1
self.faces.append((i,i+1,i+10,i+9))
i+=1
for x in range(1,7):
self.faces.append((i,i+1,64))
i+=1
self.faces.append((i,i+1,i+4,i+3))
i+=1
self.faces.append((i+1,i+2,i+3,i+4))
self.faces.append((67,66,65,62,53,44,35,26,17,8))
self.faces.append((66,67,0,9,18,27,36,45,54,63,66))
self.faces.append((0,67,8,7,5,4,3,2,1,0))
def vertsappend( self,xx,yy,zz):
if self.new_obj:
self.verts.append((xx,yy,zz))
else:
jj=self.j
self.vr[jj].co[0]=xx
self.vr[jj].co[1]=yy
self.vr[jj].co[2]=zz
self.j+=1
def sira(self,txx,tyy,tzz,apaxos,abatos,rr):
rtx= list(range(6))
self.pinakasshmeioon(rr,rtx)
ktx = txx + rr
kty = tyy - abatos + rr
self.vertsappend(txx,tyy,tzz)
self.vertsappend(txx,tyy-abatos+rr,tzz)
dix=1
diy=5
j=2
for x in range(1,6):
self.vertsappend (ktx-rtx[dix],kty-rtx[diy],tzz)
dix+=1
diy-=1
j+=1
self.vertsappend(ktx,kty-rr,tzz)
self.vertsappend(txx+apaxos,tyy-abatos,tzz)
def siraΤelos(self,txx,tyy,tzz,apaxos ,abatos,rr):
self.vertsappend(txx,tyy,tzz)
self.vertsappend(txx,tyy-abatos,tzz)
self.vertsappend(txx+apaxos,tyy-abatos,tzz)
self.vertsappend(txx+apaxos,tyy,tzz)
self.vertsappend(txx+apaxos,tyy,0)
def pinakasshmeioon(self,aktina,dr):
bhma=aktinia(15)
for x in range(1,6):
dr[x]=(aktina * math.cos(bhma * x))
#onoma,tx,ty,tz,paxos,batos,ypsos,r
tap=Tapa_L('Sm_tap',0,0,0,1.2,4,1,0.03)
tap.set_ob()
I wrote a script before in that similar way after months of trying (I am not a programmer). I had x,y & z values. There were a lot of points. I wanted to edit the Z values only. However, when you have a lot of points, it becomes very confusing and difficult to find the points to change. Is there a way to add a menu for the z values that can be edited?
Maybe you can use the "is this point selected" property and only edit the Z of the selected points?
How do you determine what points you want to edit?
@@CGPython
I had an excel example but I guess we cannot attach documents here. Basically the Z-values are elevations of the floor (lets say your house). So every they will change for every new job or house. I liked blender because I could actually animate the foundation movement of the structure.
@@ashhaf63 so you want to animate the Z values of your points?
Can you use the X, Y of the points to understand what Z the points need to be at?
What app or software did u use ?
www.blender.org/
Do you think it is possible to automate the creation of vertices, edges and faces? For the vertices and edges I was able to find a way to do it but I am stuck with the faces (vertex order problem). Here is the code to automate the creation of the vertices:
# size of cube
d = 1
# starting summit
x,y,z = 0,0,0
# coordinates listes
list_x = [x, x+d]
list_y = [y, y+d]
list_z = [z, z+d]
# calculation of coordinates (dirty nested loops)
verts = []
for i in range(len(list_x)):
for j in range(len(list_y)):
for k in range(len(list_z)):
verts.append((list_x[i], list_y[j],list_z[k]))
thank you
The first thing that comes to mind is a KDTree data structure.
You would add the verts into a KDTree, then visit the verts going counterclockwise based on the next coordinate of the vert you need. This way, you don't need to know the exact vert index to use in the face creation. You just need to know what verts at what coordinates make up the face you are trying to get.
docs.blender.org/api/current/mathutils.kdtree.html
But there might be a more elegant formula for this.
Thanks again, CGPython! Just completed this one. I kept the original vertices for the entire thing and simply added a 9th vertex for the point of the pyramid. I'm using a lot of #comments to keep track, and toggling out one set of face tuples for the next shape's tuples. I definitely got a few faces flipped or overlapping while trying to keep the 2nd Cube w/triangle faces built, but I learned a lot. I am so excited for the next one with repeating code with for loops! 🐍🟦
Yeah, comments are fantastic for keeping track of what is going on!
Thanks for sharing your experience!