Mesh repair from NextEngine scan

I am currently attempting to repair meshes obtained from the NextEngine 3d scanner. I have read the methods discussed in the “Download Scan, Cleanup, Remodel” article, but these methods don’t seem to be possible in the current version of Rhino for Mac. Many of the features discussed such as the custom display options, as well as the CheckMesh commands, are not present.

The main issue I am dealing with is that the scan data (I just have an STL file that the scan operator sent me) has produced ~1000 separate meshes, ranging from one or two faces to tens of thousands of faces. The meshes overlap in ways that seem almost arbitrary- no edge of one mesh meets up with the edge of another mesh, as far as I can tell.

Is there any hope for repairing what I have into a single watertight object? There are many holes under the fingers, etc, but I am more confused by countless overlapping yet slightly different surfaces…

I am working for a studio on a near nonexistent budget so I am restricted to Rhino for Mac or free Mac programs. Any insight is much appreciated.

handPointing.3dm (9.8 MB)

You can probably get it done on the mac- the key is that since that document was written, CheckMesh is now just part of Check.

-Pascal

Hi kschaer,

Rhino is great for almost everything, but cleaning up digitized data of the quality you´ve posted is something you never should try to do in Rhino. The outcome of the nextengine scanner is really bad, most problematic are the missing parts. A watertight mesh is attached below, because of the missing parts in the source mesh, some areas had to be filled in using various scientific algorithms.

If you would like to make changes, add details or further optimize this mesh, take a look at sculpting software like sculptris or meshmixer. Both are freely available for the mac and can import the obj file format. Rhino can export using obj.

handPointing_cg.3dm (4.7 MB)

c.

Clement,
Thank you so much! The results you got are incredible. I can finally begin to move forward with this project now. Can I ask how you achieved these results, so that I can make similar mesh repairs in the future?

Again, I cannot thank you enough.
Kaitlin

Hi Kaitlin,

thanks! The process is a bit weird, to generate a first watertight mesh, only the mesh points and their normals are used. Algorithms like poisson surface reconstruction or ball pivoting then build the actual mesh, then the outcome gets “remeshed” to get even, close to equilateral triangles. The easiest way to do this in two steps with public software on the mac would be CloudCompare (for normal generation and poisson) and a recent version of MeshMixer which has some new remeshing tools. I use it to cleanup digitized data in our scanlab. To try out ball pivoting i only know that Meshlab has this implemented, but it runs very slow and requires filtered pointclouds, which means the point density should.be almost constant. Filtering can be done in CloudCompare or MeshLab, the first would be one i prefer because of its stability.

If you do not want to go through all this, you might ask the scan operator to send you better data. :wink: I´ve been a bit surprised of the quality the nextengine scanner has delivered. According to the images on their website, it should do it much better. Alternatively, just post ugly meshes here and i will try to fix them for you.

c.