How can I create a point cloud from the surfaces of a model?

Question

How can one go about generating a point cloud from the surfaces/faces of a model?

Initially the models are going to be fairly simple (just cubes, cylinders, and spheres), but eventually the models will be progressing on to more complicated shapes.

The type of point cloud that I need to generate needs to be similar to the point cloud that would result from a laser scanner. So I do not need any edge or vertex information, just a point for every face of the mesh.

Answer 1

Following script creates a new point cloud from the selected object based the center of each face:

import bpy

def point_cloud(ob_name, coords):
    """Create point cloud object based on given coordinates and name."""
    me = bpy.data.meshes.new(ob_name + "Mesh")
    ob = bpy.data.objects.new(ob_name, me)
    me.from_pydata(coords, [], [])
    ob.show_name = True
    me.update()
    return ob

def face_centers(obj):
    """Returns median center coordinates for each face of given mesh object."""
    if obj.type == 'MESH':
        import bmesh
        bm = bmesh.new()
        bm.from_mesh(obj.data)
        return [obj.matrix_world @ f.calc_center_median() for f in bm.faces]
    else:
        return [(0.0, 0.0, 0.0)]


ob = bpy.context.active_object
pc = point_cloud(ob.name + "-pointcloud", face_centers(ob))

# Link object to the active collection
bpy.context.collection.objects.link(pc)

Related: Add a simple vertex via python?

Answer 2

Just playing around, this seems like the simplest solution, although it may have trouble on more complex models.

1. Add a remesh modifier
2. Change the remesh type to smooth (starts at sharp by default)
3. Increase the octree depth to the resolution of the pointcloud you want
4. Adjust the scale for finer changes to the resolution

To get the points, do as stacker suggested:

5. Apply the remesh modifier
6. Go into edit mode
7. Select all (a)
8. Delete edges and faces (x, select "only edges and faces")

Answer 3

You can also use this simple Geometry Nodes setup to create a Point Cloud:

You may not see any output, but when you apply the modifier, it shows as Point Cloud.