I discovered that the Brep created by Brep.CreatePatch and the Brep extracted from the BrepObject of the other Brep added to the document can be quite different. As shown below, one of the differences worth noting is in the results of Brep.ClosestPoint, where all closest points should be near pt_Test. The final value is from a workaround, calling ClosestPoint on a Brep created from the underlying Surface.
This occurs in V5, V6, and the WIP.
pt_Test: 5,0,0 pt_onPatchBrep: 4.68504544451056,2.11559526830229E-05,0 pt_onDocBrep: 5,-8.01442245901285E-16,0 pt_onPatchSrfBrep: 5,-8.01442245901285E-16,0
Brep_CreatePatch_ClosestPoint.py (1018 Bytes)