Union of "Revolve" and "Extrude" groups failed #470
Description
System information
SolveSpace version: 3.0~22e4011c
Operating system: Debian 9.x stretch (x86_64)
Expected behavior
If path for «Extrude» group based on plane from «Revolve» group boolean union operation should be correct.
Actual behavior
Boolean union of parent «Revolve» and child «Extrude» (based on plane face from «Revolve») groups failed.
