Regression: Surface Deform modifier bind to object with different viewport/render subdiv level will be buggy when rendering #108104

New Issue

himisa · 2023-05-20T15:04:16+02:00

himisa commented

2023-05-20 15:04:16 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 528.49

Blender Version
Broken: version: 3.3.0 Alpha, branch: master, commit date: 2022-06-22 08:45, hash: rBdf2ab4e758c7
Worked: version: 3.2.0, branch: master, commit date: 2022-06-08 10:22, hash: rBe05e1e369187

Short description of error
If object A has a subdiv modifier with different level for viewport/render, and object B has a SurfaceDeform modifier that bind to A.

When A is deforming in viewport, B will also deform normally in viewport. However in rendered result, B will become chaotic. Clearly the 'bind' option in B's SurfaceDeform modifier remembers A's vertices that subdived for levels of viewport setting, but when rendering, A will be subdived for levels of render setting, and have a different number of vertices, making B's bind invalid.

Any other modifiers with bind option, e.g. MeshDeform, may also suffer from this.

I wonder if this can be fixed. Two possible solutions:

for every subdiv step, add additional vertices at the end of original vertices. So the original vertices will remain index unchanged, and the bind may work as well.
When rendering, check if render subdiv level != viewport subdiv level, and always use viewport subdiv level for binding of any other modifiers. The render subdiv level should only affect render visual effect. Maybe an option for this can present in subdiv modifier, if this change may introduce incompatibility issues.

Exact steps for others to reproduce the error
Following above information, reproduce should be easy. However, an example .blend file is provided.

open example.blend. This file contains a surface with subdiv level 2/5 for viewport/render and a torus with SurfaceDeform bind to it.
F12/render and see the torus go bad.

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 528.49 **Blender Version** Broken: version: 3.3.0 Alpha, branch: master, commit date: 2022-06-22 08:45, hash: `rBdf2ab4e758c7` Worked: version: 3.2.0, branch: master, commit date: 2022-06-08 10:22, hash: `rBe05e1e369187` **Short description of error** If object A has a subdiv modifier with different level for viewport/render, and object B has a SurfaceDeform modifier that bind to A. When A is deforming in viewport, B will also deform normally in viewport. However in rendered result, B will become chaotic. Clearly the 'bind' option in B's SurfaceDeform modifier remembers A's vertices that subdived for levels of viewport setting, but when rendering, A will be subdived for levels of render setting, and have a different number of vertices, making B's bind invalid. Any other modifiers with bind option, e.g. MeshDeform, may also suffer from this. I wonder if this can be fixed. Two possible solutions: 1. for every subdiv step, add additional vertices at the end of original vertices. So the original vertices will remain index unchanged, and the bind may work as well. 2. When rendering, check if render subdiv level != viewport subdiv level, and always use viewport subdiv level for binding of any other modifiers. The render subdiv level should only affect render visual effect. Maybe an option for this can present in subdiv modifier, if this change may introduce incompatibility issues. **Exact steps for others to reproduce the error** Following above information, reproduce should be easy. However, an example .blend file is provided. 1. open example.blend. This file contains a surface with subdiv level 2/5 for viewport/render and a torus with SurfaceDeform bind to it. 2. F12/render and see the torus go bad.

example.blend

1.3 MiB

👍 1

himisa added the

labels 2023-05-20 15:04:16 +02:00

Iliya Katushenock added the