How to load/get only the surface of a solidified mesh

Hi Marco,

I have a mesh which also has internal fragmentation but as far as I know it is not tetrahedralized and it is a normal .obj file (see attached).

I want to load it or after load to get only the surface structure and ignore the internal points/faces. I’ve tried to use the .tomesh(fill=False) method but apparently there isn’t anything relevant for the Mesh class. Thus, is there any other efficient way (build in function, I would prefer it from looping over the points and checking whether the point is inside the mesh) to do that.

Thanks piece_1.zip .

[RubendeBruin]

you may want to have a look at meshlab as well: https://www.meshlab.net/

there are python bindings (pymeshlab) which are really easy to combine with vedo as the data-structure is identical:

# from vedo to pymeshlab
ms = pymeshlab.MeshSet()
mesh = pymeshlab.Mesh(vertices, faces)
ms.add_mesh(mesh)

# and back
vertices = ms.current_mesh().vertex_matrix()
faces = ms.current_mesh().face_matrix()

m2 = vedo.Mesh([vertices, faces])
p.add(m2, render=False)

I use it myself for boolean operations as they are more stable than the ones in vtk (https://github.com/RubendeBruin/pymeshup)

[ttsesm]

Actually I never looked into open3d!

Ok, then maybe I’ve seen it somewhere else… 🤔

Anyways, actually I’ve created the following functions in case you are interested to add them. It is as simple as that:

import vedo as vd
import open3d as o3d

def o3d2vedo(o3d_mesh):
    m = vd.Mesh([np.array(o3d_mesh.vertices), np.array(o3d_mesh.triangles)])

    # you could also check whether normals and color are present in order to port with the above vertices/faces
    return m

and the counter function:

import vedo as vd
import open3d as o3d

def vedo2open3d(vd_mesh):
    """
    Return an `open3d.geometry.TriangleMesh` version of
    the current mesh.

    Returns
    ---------
    open3d : open3d.geometry.TriangleMesh
      Current mesh as an open3d object.
    """
    # create from numpy arrays
    o3d_mesh = o3d.geometry.TriangleMesh(
        vertices=o3d.utility.Vector3dVector(vd_mesh.points()),
        triangles=o3d.utility.Vector3iVector(vd_mesh.faces()))

    # I need to add some if check here in case color and normals info are not existing
    # o3d_mesh.vertex_colors = o3d.utility.Vector3dVector(vd_mesh.pointdata["RGB"]/255)
    # o3d_mesh.vertex_normals = o3d.utility.Vector3dVector(vd_mesh.pointdata["Normals"])

    return o3d_mesh