How to make a mesh (having vectors perpendicular to the surface in various direction) thicker?

mesh

(Cam ) #1

Hello,

I have a quite complex mesh, coming from a 3d scan. I would like to make it thicker and then to make a booleen union with a rhino polysurface. The problem is that the vectors are in all direction (cf picture). So when I use offsetmesh command with the ‘make solid’ option, it results in a totally different mesh. What would be the best option to over come this if any? I can see two options, but dont know how to applied them:

  1. put all the vectore in the same direction: i.e. all should point inside the mesh. Then use the offset mesh with ‘make solid’ option.
  2. copy paste my mesh, and scale it smaller, and then create a olid out of these two meshes by joining the contour.

thank you very much.

image
image


(Pascal Golay) #2

Hello - it’s hard to say from your images but it looks like the normals are correct, but on a noisy mesh. My guess is - again it depends on what is inside all those arrows - that it may make more sense to re-model the scanned object.

-Pascal


(Cam ) #3

Thank you @pascal for your answer :).
It is a scan of a sea urchin, so inside is empty, and on the top there is a small hole, I attached a picture to have an idea. But I dont think that I could re-model it… or what do you meant by this?

image


#4

It is a little unclear how OffsetMesh is not working for you. Is it that the offset is self intersecting and gross? I might also try creating a MeshEllipsoid as your inside surface. You could then dupMeshHoleBoundary or DupMeshEdge the hole of the urchin to extrude that down so it intersects the MeshEllipsoid. Use the Mesh command on the resulting extrusion, then MeshTrim the meshed extrusion and the MeshEllipsoid to eachother. You will also have to Mesh the band polysurface, as you cannot Boolean / trim / join a mesh and a surface / polysurface.

Sam


(Cam ) #5

Thank you very much for this usefull information @SamPage. The offset is not working as the vectors are going in both inside and outside the oursin, meaning that at each point of the ursin the thickness is going to be added in different direction resulting in :
image

the dupmeshholeboundary is not working, rhino error: Edge must be on boundary of mesh. I also cant make it work the dupmeshedges command :(. I am still new to rhino so I am sorry for all my mistake.

My mesh hole is looking like this:

image


(Laurent Delrieu) #6

See this if it could help


If not use Meshmixer


(Cam ) #7

Thank you very much @laurent_delrieu. I unfortunately dont have grasshooper but I will have a look to it, and already tried in meshmixer and thats why I have a small thickness already, but could not manage a bigger one.


#8

You might have better results with Meshmixer, which offsets meshes by building a new mesh rather than offsetting every single face.
It has a lot of other goodies too, and it’s free…
http://www.meshmixer.com/download.html


(Cam ) #9

Thank you @cairn for this information! I will keep going with meshmixer then :slight_smile: I did not knew that it was doing in another way.
Have a nice day