private static Geometry<EntityVertex> WallsAndGables(Geometry<EntityVertex> roof, Geometry<EntityVertex> gables,
int roofSnapTag, int gableTopTag)
{
var walls = Quadrilateral<EntityVertex>.Rectangle (gables.BoundingBox.Size.X, gables.BoundingBox.Size.Z)
.Extrude (12f, false).RotateX (MathHelper.PiOver2);
var wallsAndGables = Composite.Create (Stacking.StackUp (walls, gables)
.Align (Alignment.Center, Alignment.None, Alignment.Center));
return wallsAndGables.SnapVertex (wallsAndGables.FindVertexByTag (gableTopTag),
roof.FindVertexByTag (roofSnapTag), Axes.All);
}
