See through faces

Scripting Issues
1

Hi !

Im trying to render a STL - File. The Problem is that the normals are messed up.

This leads to parts of the model beeing seethrough.

In order to counter this effekt I called:
.setTwoSided(True)

However this leads to black faces…

image
image1576×1267 60.1 KB

How can I fix this?

2

In fact, specialized editors such as blender are better suited for this. I don’t think you can fix this in Panda.

3

I fixed it. Things I didn’t know and helped me fixing it:

  1. Backfaceculling only relies on the order of the vertices. It generates its own normal vert for each triangle.
    vert1, vert2, vert3 -> normalvert
    vert2, vert1, vert3 -> -normalvert
  2. This internal normalvert is independant of the normals you pass to the mesh. The normals passed to the mesh only effect the shading / lighting of the triangle.
  3. Every single vert needs a normal

So in order to fix it. I simply duplicated all vertices, half of them rearranged to avoid the backfaceculling.
Then duplicate all normales, and flip half of the normals.
That way I had true double sided rendering without weird shading.

1 Like