Unify Mesh Normals for 3d Printing

Rhino Rhino for Windows
1

Hi,

I am trying to prepare a model for 3d printing. I first modeled the object as a group of surfaces. Then, I converted them into meshes. Half of the normal of the faces are pointing in and the other half out. I can flip them manually, but I would like to figure out how to flip the ones facing in quickly. I have tried to weld the meshes and then unify mesh normals, Although this has no effect on my model. I have also tried to explode it before performing the weld and unify mesh normals, but that didn’t change the result either. I would appreciate the help.

Thanks Kevin

2

Hi Kevin - if the surfaces are all within tolerance at the edges, try Join, make sure the resulting object is closed (ShowEdges > Naked edges) and then create the mesh from that.

-Pascal

3

I don’t know what you mean by within tolerance. Can you explain? The model prints when all faces are facing out if that clarifies anything.

4

Within tolerance = edges are common for adjacent faces and allow to Join faces into one object. You need a watertight object = a closed (poly)surface to create a closed mesh with Mesh command.
Can you post your file?

5

SPL 1.3dm (147.7 KB)

6

Join your 24 surfaces. It will form one open polysurface. ShowEdges to see where naked edges are (image below). I have removed this face (ExtractSrf, Delete) and recreated it with Sweep2. Join again to get a closed polysurface. Mesh and you will get a good, closed mesh, ready for 3d printing (Export as STL).
SPL 002.3dm (102.2 KB)

1 Like
7

I guess i wasn’t clear on my problem. I can get it to print no problem. I want to know why when I try to unify mesh normals nothing happens.

8

You should Join surfaces in advance, then Mesh, then Check and UnifyMeshNormals if required (based on what Check tells you).

Nothing happens because you’ve got unjoined, seperate objects - so there is no common direction to unify.

1 Like
9

Ok, Thanks