BREP compatibility issue

[Quaoar]

Regarding the BREP compatibility issue mentioned above, here are some additional details.

People who are going to migrate to OpenCascade 7.6 from an earlier version should anticipate that the new BREP files (*.brep) won't open in the older versions of OpenCascade. Kirill (the former architect of OpenCascade, now the team is almost completely gone) has explained this whole business in his blog here: https://unlimited3d.wordpress.com/2021/09/08/xcaf-b-rep-changes-in-occt-7-6-0/

Unfortunately, Analysis Situs could not easily migrate to OpenCascade 7.6 (or 7.5) because of many regressions such a switch is going to induce. There's simply no sense in such a migration. At the same time, I want the software to be compatible with FreeCAD and all other tools that could export BREP and could happen to migrate to OpenCascade 7.6 and newer at some point. That's why forking OpenCascade and fixing the upward compatibility issue locally seems to be the only choice we've got for Analysis Situs. Here is the fork: https://gitlab.com/ssv/opencascade

This fork concerns Analysis Situs only and the SDK around it. All youtube lessons and code samples will keep using the official versions of OpenCascade.

 

[Quaoar]

Here is an update. We finally took time and migrated Analysis Situs to OpenCascade ver. 7.6. This version of the kernel is going to stay our main workhorse for a while, unless we get into some new troubles. The motivation for the recent update was two-fold:

1. This was a requirement from a customer's project dictated by the necessity of porting to a newer version of cadex libs.
2. We wanted to take advantage of some fixes in STEP reader (like STEP files saved from newer versions of SolidWorks won't open in older OpenCascade).
3. BREP compatibility issue is pretty annoying, and we wanted to finally get rid of it.