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Subdivision Surface- Edge Crease - BUG
Closed, InvalidPublic

Description

System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: AMD Radeon HD 7600M Series ATI Technologies Inc. 4.5.13417 Core Profile Context 0

Blender Version
Broken: version: 2.81 (sub 3), branch: master, commit date: 2019-08-28 03:44, hash: rBf88022b96f3a
Worked: (optional)

Short description of error
in a primitive plane, not subdivided, the outer sides are not influenced by the "edge crease" operator.
this happens even in other conditions with various subdivisions ...
look at the picture.

Exact steps for others to reproduce the error

Details

Type
Bug

Event Timeline

This has always worked like that. 2.79:

already, maybe because of subsurf, but it's still a bug.
because if I want the maximum of the edge crease, it should behave as I say ... instead it ignores the maximum crease ... and some cases it works, in others it doesn't.

if they want to maintain compatibility with the old system, in importing old models, at least they would allow the maximum extension to be reached at "2,000" or "1,500"
the old models will have all parameters that will not go beyond "1,000" of crease

We do not handle user support on this tracker, only bug reports. User forums like blenderartists.org or blender.stackexchange.com and our devtalk should be used for that matter.

No bug here, that is how subsurf is supposed to work, if you want a vertex to be sharp, then all edges leading to that vertex must have maximum crease…

Bastien Montagne (mont29) claimed this task.

@Bastien Montagne (mont29) better to investigate, I believe there is a bug here, (maximum crease apart) from time to time the creased edge stops working totally.

This is going down to how subsurf calculates vertex crease: is based on the average crease of an adjacent edges, which is not enough to pull the corner and make it sharp in this case.

Possible workaround is to give a crease to the diagonal edge. That will make the outer corner sharp, but will also affect on the inner loop.

proper solution is to add support of vertex crease, which is now possible with OpenSubdiv. This is a planned work, but is happening as a regular development and not as a bug tracker work.

@Sergey Sharybin (sergey)
thank you very much for the explanation.

good to know that an upgrade is planned ..
because I tried to adopt the modeling similar to BREPs https://en.wikipedia.org/wiki/Boundary_representation , and currently it is not possible to do it as I would like.