Hello Paulus,
I would try to work only in 2D: projecting the plane to a line in the XY plane. Also, project the points on the XY plane. Once done, the problem just simplifies in only one constraint:
- Defining y=mx+n the projected line on the XY plane and A(xa,ya) an arbitrary point containing the XY coordinates from the 3D mesh:
- If ya>y(xa)=mxa+n the point is on the 'left'
- If ya<y(xa)=mxa+n the point is on the 'right'
Also, you will need to include the point inside the line case and give it a value (left or right).
If you pass the data including the 3D mesh and the plane I could work on a code. I hope that this explanation helps.