object and vertex group

Coding Python Support
1

is there a way to find vertices inside a vertex group in an object and how
with al little script

Thanks

2

Assuming you know the name of the vertex group, and want the indices of the vertexes in the group (and assuming its a mesh object, which you may want to check):


import Blender
from Blender import Object
 
ob = Object.Get("MyObject")
me = ob.getData(mesh = True)
vgIndex = me.getVertsFromGroup("The Group I Want")

You can then iterate through vgIndex to do stuff like location, etc.

3

but what happen if you don’t know the name of the vertex group?

you may know the object name and that there is one vertex group wiht a certain qty of vertices and want to get the location of theses vertices

anyway to get this info ?

Thanks

4

You sure can:


import Blender
from Blender import Object
 
ob = Object.Get("MyObject")
me = ob.getData(mesh = True)
verts = None
theLengthIWant = 1 # your number
for name in me.getVertGroupNames():
     verts = me.getVertsFromGroup(name)
     if len(verts) == theLengthIWant:
          break
     else:
          verts = None
 
if verts == None:
     print 'No vertex group with %d vertexes found', %(theLengthIWant)
else:
     # You can continue on...
5

for the first part in

vgIndex = me.getVertsFromGroup(“The Group I Want”)

this means that you already have the VG name then
how do you go through the list of vertex

i mean Vgindex would contain the list of vertices inside the Vextex group only
or also all the edges and faces associated with it ?

Thanks

6

Just looking along these lines myself:


ob = Blender.Object.Get(mesh_name.val)
if str(ob.type)=='Mesh':
    mesh = ob.getData()    
    if hasattr(mesh,'getVertGroupNames'):
        mesh_groups = mesh.getVertGroupNames()
        vv = mesh.getVertsFromGroup(mesh_groups[mesh_group_sel.val])
7

My question is, how do you update the vector elements?


mesh.verts[0].co[0] = numx.val
8

Just iterate through the verts member of the mesh:


for vId in vgIndex:
    vert = me.verts[vId]
    # Continue your processing

It just contains the list of vertex indices. If you want the edges or faces it will require additional processing. There was a thread not too long ago that had how to find the faces in it, and edges are not much different (they’re probably easier).

9

Just wondering about the object portion of this question.

How can I find out what group an object belongs to? (Not Vertex)

10

that type of group has nothing to do with object group!

so may be better start a new thread on this subject !

salutations