Problem with grass on mesh from ArchiCad

Hi,

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

ground.zip (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.