Rebuilding vertex count with python?

I am trying to rebuild the number of vertices with a target count.

How do I come about doing this with python?
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Determine the total length of your existing edges, divide that distance by your target vert count, then use basic linear algebra to interpolate the new points along the existing path.

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Haha, I wish I had the brains to do that. Unfortunately I am not experienced for that since I am a beginner with python. Have been taking courses for a while.

Something like this?

import bpy
import bmesh


me = bpy.context.object.data
bm = bmesh.from_edit_mesh(me)
#list to populate with lengths
edge_lengths = []
#if edge is selected, get its length
for e in bm.edges:
    #if e.select:
    edge_lengths = e.calc_length()
#print(edge_lengths)


count = 10


target = edge_lenths / count

No luck…

basic example:

imagine that you have an existing “spline” consisting of 10 verts (9 segments/edges) and a total length of 9cm. For simplicity’s sake, also imagine that each edge is the same length: 1cm.

if your new target vert count is 20 (19 segments/edges), it needs to travel the same total length, which means your target segment length is 0.5cm. It’s just a matter at starting at the first vert position and moving along the existing ‘spline’ creating new verts every N units.

since mathutils already has code for interpolating vector positions, you can use that and save yourself some time:

# "t" needs to be between 0 and 1, in our case it will be 0.5
t = target_segment_length / segment_length 
new_vert_pos = vertA.lerp(vertB, t)
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What does vertA/vertB represent?

depends on where you are in your loop. for example:

for i, v in enumerate(my_verts):
    if i == len(my_verts) - 1:
        break
    vertA = v.co
    vertB = my_verts[i + 1].co
1 Like

Okay, I have this, but not too sure about the v.co part, do I assign that as “new_vert_pos” ? Also would be nice to decrease and increase target count

import bpy

import mathutils

import bmesh


obj = bpy.context.object

me = obj.data
bm = bmesh.from_edit_mesh(me)

edge_lengths = []

for e in bm.edges:
    #if e.select:
    edge_lengths = e.calc_length()



my_verts = [v for v in bm.verts ]#if v.select]


for i, v in enumerate(my_verts):
    if i == len(my_verts) - 1:
        break
    vertA = v.co
    vertB = my_verts[i + 1].co
    

    
count = 20


t = count / edge_lengths 

new_vert_pos = vertA.lerp(vertB, t)


I was thinking merging by distance until the vertex count is at target count
Would the while loop work for this?