Complex Large Mesh Hole To Close - Best Process

Serengeti (Rhino WIP) Mesh WIP
1

Hi All,

I have a scanned head mesh (436K faces).
The person had a poney tail and I was no able to capture the details of the poney tail properly.

Does someone have a workflow to close this hole while keeping the shape as close as posisble to the scanned data? Ideally, only the poney tail is reworked.

I tried

  • duplicate border
  • patch surface
  • trim

The surface obtained does not fit exactly though and I am unable to join the new surface with the mesh. Could a solid be created that follows the mesh easily (contour for instance?) and then unioned? I looked at it but could not make it work either.

Thank you in advance for your support.

Tom

ScannerHeadMeshIssue.3dm (15.8 MB)

2

Using SSD or Poisson reconstruction on the mesh boundary gives a mesh which could be used to close the model anfter trimm and self-intersection cleanup.

grafik
grafik808×1046 186 KB

Does this point into the right direction?

3

Hi Tom,

scanned mesh repair is not Rhino’s strongest part. Trying to repair meshes by using nurbs surfaces can be quite tedious. One way to repair such cases in Rhino is to use

TriangleMeshCompleter.

I used _Weld before with maximum (180°) angle and removed a few faces of the ponytail which intersect the backhead.

To close the mesh at the bottom of the ponytail i used MeshMixer and brushed a bit…

grafik
grafik1111×900 53.4 KB

ScannerHeadMeshPony.3dm (14.4 MB)

_
c.

4

Hi Stefan,

Thank you for your answer, i really appreciate your help!

I searched these functions in the Rhino command, but could not find these.
Are they GrassHopper functions?

Could you please let me know how I could replicate your picture?
Are there parameters to choose where the newly created red surface would connect to the existing mesh?

Tom

5

Hi Clement,

I have indeed found it very labour intensive to repair meshes :frowning: .

I followed the TriangleMeshCompleter link; but only saw plugins up to Rhino 5.
Is this compatible with 7?

Your process is very clear and the results look good!
How long did it take you to get this result?

I do appreciate your help and fast answer!
Thank you.

Tom

6

Thanks Tom,

i noticed that too and used Rhino 5. Maybe we should contact the developer and ask if there could be an update for newer Rhino versions ? The PlugIn has been really useful for such cases in the past.

10min, but i do this often.

_
c.

7

Thank you Clement - I will contact them and repost their reply here. 10 mins would be great compared to the time i spent trying haha!

8

Hi Tom.
The commands are not available in rhino yet. if there is enough intereset for such a type of solution we will start thinking to make it available as a plugin.
ponytail-filled-iCapp-open-Boundaryd.3dm (15.2 MB)
the attached model ha the fill in trimmed, but still with incompatible discretization at the boudary to the original, but this is only a small technical hurdle to overcome.
Result could be obtained by the click of a button.
KR
Stephan

9

Hi Stefan,

OK, all clear for the commands.
Checking the file you sent, this solution is indeed interesting.
The bottom part could as well easily be cleaned.

I think there would still be work to obtain a similar smoothness to the added surface as the one from the original scan.

Thank you for the file and the answers.

Tom

10

Hi Tom
What do you mean with lack of similar smoothness?
Clearly there are infinitely many surfaces which interpolate the vertices and surface normals along the given boundary. Typically this surfaces have less ‘detail’ than the scan itself, but will have G1 continuity up to dicretization errors. The choice of base function for the interpolation will somehow affect the shape of the surface.
So your are missing the continuation of the ‘characteristics’ of the pony tail in the filling surface?
Stephan

11

Hi Stefan,

So your are missing the continuation of the ‘characteristics’ of the pony tail in the filling surface?
Yes indeed. We can see that the hole was fixed as the surface looks so different (less detail as you mention) from the rest.

is there anything that could be done about that?

Thank you

Tom

12

Yes, brushing aka sculpting. Every Ponytail needs a brush sometimes :wink:

_
c.

13

I know about no other method than to provide auxiliary curves or points which are used to shape the filling surface. As i said doing it automatically looks impossible for now because the target is ill-defined.
Think about the task to specify mathematically what is ‘continuation of the characeteristics’ ?
Stephan