Subsurf modifier and multirres modifier give different results when subdivide #75632

New Issue

Tonatiuh de San Julián · 2020-04-11T20:48:42+02:00

2020-04-11 20:48:42 +02:00

System Information
Operating system: Linux-5.3.0-46-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 435.21

Blender Version
Broken: version: 2.83 (sub 13), branch: master, commit date: 2020-04-10 21:07, hash: a8d139ca20; 2b95f2439e
Worked:

Short description of error
Subsurf modifier and multirres modifier give different results when subdivide

Exact steps for others to reproduce the error
Add Susan, make three copies
1 Use multirres in one of the copies with 2 subdiv
2 Use one subsurf modifier with 2 subdivisions
3 Use the last one with two modifiers, each with one subdivisions

The number 1 and 3 are a match, but the number 2 is different.

#75632.blend
Open file & turn on visibility of the three monkeys which have different colors.

**System Information** Operating system: Linux-5.3.0-46-generic-x86_64-with-debian-buster-sid 64 Bits Graphics card: GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 435.21 **Blender Version** Broken: version: 2.83 (sub 13), branch: master, commit date: 2020-04-10 21:07, hash: a8d139ca20; 2b95f2439e Worked: **Short description of error** Subsurf modifier and multirres modifier give different results when subdivide **Exact steps for others to reproduce the error** Add Susan, make three copies 1 Use multirres in one of the copies with 2 subdiv 2 Use one subsurf modifier with 2 subdivisions 3 Use the last one with two modifiers, each with one subdivisions The number 1 and 3 are a match, but the number 2 is different. ![Screenshot from 2020-04-11 20-46-35.png](https://archive.blender.org/developer/F8465269/Screenshot_from_2020-04-11_20-46-35.png) [#75632.blend](https://archive.blender.org/developer/F8494066/T75632.blend) Open file & turn on visibility of the three monkeys which have different colors.

Tonatiuh de San Julián commented

2020-04-11 20:48:42 +02:00

Added subscriber: @TonatiuhdeSanJulian

blender-admin commented

2020-04-11 20:48:42 +02:00

#74928 was marked as duplicate of this issue

Tonatiuh de San Julián commented

2020-04-11 20:57:30 +02:00

Also I think related to this the aplay base gives strange results:

steps to reproduce:

Add a Susan, give it a multirres modifier with two subdivisions. Apply to base. Then make a copy, in the copy remove the modifier, and give another multirres and subdivide two times, the results are different.

Also I think related to this the aplay base gives strange results: steps to reproduce: Add a Susan, give it a multirres modifier with two subdivisions. Apply to base. Then make a copy, in the copy remove the modifier, and give another multirres and subdivide two times, the results are different. ![Screenshot from 2020-04-11 20-54-07.png](https://archive.blender.org/developer/F8465300/Screenshot_from_2020-04-11_20-54-07.png)

Tonatiuh de San Julián commented

2020-04-11 20:58:38 +02:00

https://developer.blender.org/T75631 this one maybe related

Tonatiuh de San Julián commented

2020-04-11 21:03:02 +02:00

If you do the apply base thing again and again you get something like this:

If you do the apply base thing again and again you get something like this: ![Screenshot from 2020-04-11 21-02-45.png](https://archive.blender.org/developer/F8465313/Screenshot_from_2020-04-11_21-02-45.png)

Jesse Yurkovich commented

2020-04-11 21:13:41 +02:00

Added subscriber: @deadpin

Jesse Yurkovich commented

2020-04-11 21:13:41 +02:00

Most likely the same as #74928. Multires internally acts like more than one modifier in a stacked fashion (1 and 3 above). But having a single modifier (2) seems to match what the other bug is saying.