Problem with grass on mesh from ArchiCad


I have a problem with adding hair particle system (grass) to mesh imported from ArchiCad. I need emiter which is simple 2d plane, so grass would grow only up, but this is object with normals pointing in every directions. I have tried intersect it with a new plane, but nothing happend (cannot execute boolean operation error).

Maybe there’s a way to convert 3d object into 2d in similar way it can be projected into flat uv map?

Blend file attached.

Attachments (308 KB)

The topology in that object is a complete mess. You need to fix that before you do anything else. I normally wouldn’t recommend this, but you might consider using the Remesh modifier on this. You’d probably be better off retopologizing it by hand, but I don’t know what kind of accuracy you need in the shape.