Average surface from 3 surfaces

Rhino
1

Hello community,

I’m facing the following issue and would like to ask for your experience. I have 3 surfaces that I 3D scanned and saved as STL files. They are almost identical in structure. I want to generate one surface from these three, essentially as an average.

How could I do this in Rhino or/and Grasshopper?

I tried using Grasshopper with DeMesh, Average, and ConMesh, but unfortunately, I can’t get any further with my current level of knowledge.

Do I need to rebuild my 3 surfaces beforehand so that they have the same number of points?

I would appreciate any tips for the next steps. Thank you in advance!

(I`m using Rhino 6)

2

A file or an image would go a really long way - then people won’t have to imagine what your problem might be

3

As they are .stl’s, they are meshes… I might use ExtractPt to extract the mesh vertices as points, then run Patch through the points to get an ‘average’ surface. Play with the stiffness and UV count values to get the desired degree of conformity with the points.

4

Please post file
Or at least screenshot + statistics of meshes

5

Hello everyone,
I’ve adjusted/cutted the surfaces a bit, one of them didn’t work out cleanly for some reason. Therefore, I’m only attaching two as STL files. In principle, these two are sufficient to create an averaged version.

surface_2.stl (11.0 MB)

surface_1.stl (14.0 MB)

6

something like this is possible via script:

image
image2145×1491 2.24 MB

pull all vertices from the blue mesh to the black mesh.
use the midpoint between old vertex and pulled point as a new vertex location.
… assuming the initial meshes where well aligned.

download 36MB via wetransfer:

hope this helps - kind regards - tom

7

Hi @RomT,

I know you have asked specifically about Rhino and Grasshopper, but you’d probably be better off for this particular task if you used Blender.

Here’s a discussion on how to do it there:
mesh - How can I average two meshes together? - Blender Stack Exchange

Regards
Jeremy

8

Thank you!
Unfortunatelly i cannot download from external sources. Could you post the script as text?

I am not sure about, if the meshes are well aligned. How can i check it?

9

i uploaded a 30mb rhino file - i think the size level in this forum is 10 or 20 mb

10

Hi Tom, thank you. I’ve found a solution in the meantime, directly in Rhino using patch and so on. It’s quite manual, but it worked for now. Thanks to all of you for your support!