Analysis > Options > Collapse

Merge adjacent surfaces – during intersection analysis.

Surfaces that share common edges and can be collapsed into a single quadrilateral, will be, provided they are parallel to one another.

Notes

This function must be checked before conducting the intersection analysis

Analysis > Intersections.

This can result in a large reduction in problem size significantly reducing analysis time.

It is recommended that you check this option unless you specifically do not want adjacent surfaces to be merged.