How to delete vertices that are not part of a face using python

Question

I want to delete vertices that are not part of a face (as for example the selected ones in the image) using python. What I tried so far is:

• switch to face select mode
• select all faces
• switch to vertex select mode
• invert selection
• delete vertices

This method is very unstable though, blender crashes every other time.

Answer 1

This code will do literally the same thing as you suggest. It operates on the active object. Change the line that starts object = to the object you want, if you don't want to use the active object.

import bpy
import bmesh

object = bpy.context.active_object

if object.mode == 'OBJECT':
    bm = bmesh.new()
    bm.from_mesh(object.data)
else:
    bm = bmesh.from_edit_mesh(object.data)


bm.verts.ensure_lookup_table()
bm.faces.ensure_lookup_table()

for face in bm.faces:
    face.select_set(True)

for vert in bm.verts:
    vert.select_set(not vert.select) 
    
for vert in bm.verts:
    if vert.select:
        bm.verts.remove(vert)

if object.mode == 'OBJECT':
    bm.to_mesh(object.data)
    bm.free()
else:
    bmesh.update_edit_mesh(object.data)

There are other ways to do this; but this is the simplest to follow. For example, the two loops through bm.verts can be combined to one loop, by noting that all of the verts you want to delete are deselected after you've selected all the faces. So those two loops become simply

for vert in bm.verts:
    if not vert.select:
        bm.verts.remove(vert)