create mesh then add vertices to it in python

Question

I would like to create a mesh, then interactively add vertices (afterwards, possibly through a loop) to it through python.

Is that possible?

I can't find enough info from other answers to really get this going - either I find out how to create a mesh, or how to add a vertex, but can't seem to put them together in to a script.

Nowadays you'll want to use bmesh...I don't have time to write a full answer, but I will later if no one else has. — JakeD, Aug 29 '16 at 12:32
related: http://blender.stackexchange.com/questions/414/how-to-use-bmesh-to-add-verts-faces-and-edges-to-existing-geometry?rq=1 — zeffii, Aug 29 '16 at 12:42
related: http://blender.stackexchange.com/questions/2407/how-to-create-a-mesh-programmatically-without-bmesh/2416#2416 — zeffii, Aug 29 '16 at 12:44
if those two links aren't helpful, please your edit question to include more details about what exactly you don't understand. — zeffii, Aug 29 '16 at 12:45

score 29 · Accepted Answer · answered Aug 29 '16 at 15:04

This is how to create a new object and add the vertices in the verts list:

import bpy
import bmesh

verts = [(1, 1, 1), (0, 0, 0)]  # 2 verts made with XYZ coords
mesh = bpy.data.meshes.new("mesh")  # add a new mesh
obj = bpy.data.objects.new("MyObject", mesh)  # add a new object using the mesh

scene = bpy.context.scene
scene.objects.link(obj)  # put the object into the scene (link)
scene.objects.active = obj  # set as the active object in the scene
obj.select = True  # select object

mesh = bpy.context.object.data
bm = bmesh.new()

for v in verts:
    bm.verts.new(v)  # add a new vert

# make the bmesh the object's mesh
bm.to_mesh(mesh)  
bm.free()  # always do this when finished

This is how to alter an existing mesh:

import bpy
import bmesh

verts = [(1, 1, 1), (0, 0, 0)]  # 2 verts made with XYZ coords
mesh = bpy.context.object.data
bm = bmesh.new()

# convert the current mesh to a bmesh (must be in edit mode)
bpy.ops.object.mode_set(mode='EDIT')
bm.from_mesh(mesh)
bpy.ops.object.mode_set(mode='OBJECT')  # return to object mode

for v in verts:
    bm.verts.new(v)  # add a new vert

# make the bmesh the object's mesh
bm.to_mesh(mesh)  
bm.free()  # always do this when finished

@HelloGoodbye I used to be pycoder...changed my name when I started joining more SE websites. You'll see this kind of references all over the sites since there is no good renaming system. — JakeD, Sep 04 '18 at 16:02
AttributeError: 'bpy_prop_collection' object has no attribute 'link' Error: Python script failed, check the message in the system console — Damn Vegetables, May 25 '20 at 13:34

score 18 · Answer 2 · edited Jul 23 '22 at 00:15

18

In Blender 2.80 onward:

import bpy
mesh = bpy.data.meshes.new("myBeautifulMesh")  # add the new mesh
obj = bpy.data.objects.new(mesh.name, mesh)
col = bpy.data.collections["Collection"]
col.objects.link(obj)
bpy.context.view_layer.objects.active = obj
verts = [( 1.0,  1.0,  0.0), 
         ( 1.0, -1.0,  0.0),
         (-1.0, -1.0,  0.0),
         (-1.0,  1.0,  0.0),
         ]  # 4 verts made with XYZ coords
edges = []
faces = [[0, 1, 2, 3]]
mesh.from_pydata(verts, edges, faces)

We can make a function, too.

import bpy
def add_mesh(name, verts, faces, edges=None, col_name="Collection"):

    if edges is None:
        edges = []
    mesh = bpy.data.meshes.new(name)
    obj = bpy.data.objects.new(mesh.name, mesh)
    col = bpy.data.collections[col_name]
    col.objects.link(obj)
    bpy.context.view_layer.objects.active = obj
    mesh.from_pydata(verts, edges, faces)
verts = [( 1.0,  1.0,  0.0), 
         ( 1.0, -1.0,  0.0),
         (-1.0, -1.0,  0.0),
         (-1.0,  1.0,  0.0),
         ]
faces = [[0, 1, 2, 3]]
add_mesh("myBeautifulMesh_1", verts, faces)
verts = [( 3.0,  1.0,  0.0), 
         ( 3.0, -1.0,  0.0),
         ( 2.0, -1.0,  0.0),
         ( 2.0,  1.0,  0.0),
         ]
add_mesh("myBeautifulMesh_2", verts, faces)

edited Jul 23 '22 at 00:15

RPaladin

1,235
1
5
17

answered Nov 26 '19 at 00:47

ludiccc

281
2
4

Can you please expand your answer a little bit more. How would you add mesh2 = bpy.data.meshes.new("myBeautifulMesh_2") to mesh? – Michael Jan 17 '20 at 16:09
Do not use mutable default arguments https://docs.python-guide.org/writing/gotchas/#mutable-default-arguments Other than that, it works great, thanks! :) – Luka Mesaric May 24 '20 at 11:29
Why do you have edges = [] mesh.from_pydata(verts, [], faces) in the first script? Didn't you mean mesh.from_pydata(verts, edges, faces)? – Damn Vegetables May 25 '20 at 13:38
@LukaMesaric: Nice catch! Edited. – ludiccc May 26 '20 at 14:49
@damn-vegetables : also, nice catch. Thanks. – ludiccc May 26 '20 at 14:50

create mesh then add vertices to it in python

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