I am playing around with trying to subtract text from a mesh using csg2 and not having much luck with it. I am getting the error: Error while creating the CSG: Not manifold
I have done a lot of searching and try different things but nothing seems to work, any ideas?
Here is the playground link
Your playground doesnât work.
But I can guess the issue. 3D text is simply not manifold, not watertight, as it has hard edges (distinct front and back faces). Youâd likely need to merge all duplicate points and possibly also separate each manifold letter mesh and subtract one at a time.
Even after doing this, Iâd be very surprised if you got reliable and clean results from using 3D text (a complex mesh) in a CSG operation.
I realized the link was bad and updated it. Is there now way to subtract text from a mesh?
Youâd need to also update the PG link in the original post, as I tried again and itâs still broken.
As I said, youâd first need to make the text mesh manifold/watertight by merging mesh vertices and possibly also separating each manifold letter mesh and subtract them one at a time. Thatâs technically possible I guess but honestly not worth the effort and the results I can guarantee will not be reliable, repeatable or clean.
Just my opinion. Maybe someone else will have better ideas âŚ
I updated the PG link again, I switch the text to MeshBuilder.CreateText and now I get the error
Error while creating the CSG: memory access out of bounds
Do you want a literal 3d subtraction, or do you want the visual effect of (inset) text on a mesh surface?
If the latter, consider a normalMap (aka bumpMap) generated from a DynamicTexture fed through HeightToNormalMap.
I am wanting a literal 3d subtraction
I think this is the right track. Changing A to I (capital I has no holes) results in no CSG2 error. However, subtract doesnât appear to do anything, and intersect results in âUnable to build mesh. Manifold has 0 vertex.â
This indicates to me that âIâ is not watertight. Not sure why it couldnât be constructed as watertight. Just speculating.
I tried a similar thing - using an âlâ (lower case l) which essentially is a box. What I found though was that even after mesh.forceSharedVertices() there were double the number of faces i.e. 24 instead of the expected 12, even though vertices was the correct 8. So I think the text is built as double-sided which could cause issues.
The âNot manifoldâ error means that the mesh or text is not closed. Make them closed: extrude the text, close any holes, merge vertices, and ensure the normals are correct.
For that effect, I think youâd be better off with a simple normal map, as @HiGreg suggested. Far less effort and far more performant:
I got this to work using a stl. I subtract the stl from the cube, then add a shorter cube to the original since the subtract seems to goes all the way through the cube.
