Maniphest T80211

Adding subdivision surface modifier freezes (or takes incredibly long) with a certain mesh
Closed, Duplicate
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Assigned To
None
Authored By
Jason Clarke (jtheninja)
Aug 29 2020, 2:53 AM
Tags
  • BF Blender
Subscribers
Jason Clarke (jtheninja)
Jesse Yurkovich (deadpin)

Description

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 452.06

Blender Version
Broken: version: 2.90.0 Beta, branch: master, commit date: 2020-08-25 16:00, hash: rB21cb6f09ffa8

Short description of error
When adding a subdivision surface modifier to the object in the attached .blend file, Blender will lock up for some time (I haven't seen it actually finish, it's possible it might at some point?)

Even when removing the modifier and merging vertices by distance to clean the mesh up a bit, the problem remains

I wish I could describe in the report what it is about this mesh specifically that led to this, but I'm out of ideas

Exact steps for others to reproduce the error
Open the attached .blend file, and attempt to add a subdivision surface modifier to the object inside.
Blender will freeze calculating, as though this mesh was many times higher poly than it actually is.

subdiv_freeze.blend175 KBDownload

Related Objects

Event Timeline

Jason Clarke (jtheninja) created this task.Aug 29 2020, 2:53 AM
Jesse Yurkovich (deadpin) added a subscriber: Jesse Yurkovich (deadpin).Aug 29 2020, 6:11 AM

The problem is due to the very large n-gon on the bottom of your model which OpenSubDiv does not handle well (it's 256 verts; very large, very bad). Removing that ngon entirely, or Triangulating it, or quad-capping the hole will all yield much better performance.

This is really a duplicate of T60733 where most of the other non-quad-mesh / large n-gon bugs ended up.

Evan Wilson (EAW) closed this task as a duplicate of T60733: Subdivision Surface Performance Degrades Markedly With Non-Quad Meshes.Aug 30 2020, 7:33 AM