Missing mesh faces

Hi, I am working on importing models of building from GIS (shape files). My goal is to create meshes based on the data I import. My problem is that in some cases, final mesh is missing few faces and looks incomplete.

Data that I work with: Collection of 8 triangles that represent 4 side walls + collection of 2 rectangle polygons that represent top and bottom of the building.

If I create separate mesh with Mesh.CreateFromPlanarBoundary with default meshing parameters and append them, it works fine. Problem is that Rhino splits each triangle triangle into several faces that impacts complexity of the whole model. If I try the same with MeshingParameters.FastRenderMesh with Shaded View it again looks like there are faces missing.

Is there something to be more careful about?

Have you checked that the mesh normals are unified?

I did give it a try. It fixes some buildings but break others.

Right now I create one mesh to which I add vertices and faces (sides) to which I want to append two other meshes for both top and bottom of the building.

At the end I call


It works when the meshes for top and bottom are created using default MeshingParameters and Mesh.CreateFromPlanarBoundary method. But not when it’s created using MeshingParameters.FastRenderMesh

At which point do you think I could call UnifyNormals?