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Bevel bug shading issues
Closed, InvalidPublic


System Information
Win8 64, 2x MSI Lightning

Blender Version
Broken: (example: 2.70 c08c931, see splash screen)
Worked: (optional)

Bevel modifier causes shading error

Exact steps for others to reproduce the error

See attached blend file.

Trying to bevel another horizontal edge loop manually with the bevel tool moves the shading issue to the new bevelled edge while old edge issue goes away.



Event Timeline

Vlad Mafteiu Scai (00Ghz) set Type to Bug.
Vlad Mafteiu Scai (00Ghz) created this task.
Vlad Mafteiu Scai (00Ghz) raised the priority of this task from to Needs Triage by Developer.
Bastien Montagne (mont29) triaged this task as Normal priority.

Some nasty geometry is generated here… :)

Sorry, I am just getting around to looking at this. I can't see the problem that I am supposed to see. What "shading issue"? Can you show me a screenshot and scribble on it to show what I should look at please?

Inspection of the mesh indicates that the bevel modifier is creating folded geometry at the corners and in the form of back-facing polygons all the way around (linked to the corner problem).

This behaviour is somehow linked to the BevelModifier.angle_limit function. In this case, the folded geometry occurs when that setting is at 30 degrees or less.

Julian Eisel (Severin) closed this task as Invalid.

Yep, as @Ignatz (ignatz) said, here we have overlapping geometry which causes the weird drawing. it can be corrected by either chaning the angle (also as @Ignatz (ignatz) said) or by moving one of the surrounding edge loops a tiny little bit.

Again, this is a case where we could make our algorithms a bit smarter, but that would be another todo (tm).
So thanks for the report but I can't see anything that we'd consider as a bug here.