Cycles experimental mode causing extreme memory consumpstion and long render times with adaptive subdiv #63972

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Matthew Vanscoy · 2019-04-29T00:03:47+02:00

Matthew Vanscoy commented

2019-04-29 00:03:47 +02:00

System Information
Operating system: windows 10
Graphics card: vega 56

Version 2.80.59

Short description of error
in cycles experimental mode, using the adaptive subdiv modifier causes extreme memory consumption with unessisarry tessellation

all I did was enable experimental mode and enabled dyanimic sub div to most of the model. I reduced max sub div to 0 but its still extreme
Final model matthew .blend

**System Information** Operating system: windows 10 Graphics card: vega 56 Version 2.80.59 **Short description of error** in cycles experimental mode, using the adaptive subdiv modifier causes extreme memory consumption with unessisarry tessellation ![1.png](https://archive.blender.org/developer/F6989830/1.png) all I did was enable experimental mode and enabled dyanimic sub div to most of the model. I reduced max sub div to 0 but its still extreme ![2.PNG](https://archive.blender.org/developer/F6989851/2.PNG) [Final model matthew .blend](https://archive.blender.org/developer/F6989834/Final_model_matthew_.blend)

Matthew Vanscoy commented

2019-04-29 00:03:47 +02:00

Added subscriber: @Matthewv1998

Bent Hillerkus commented

2019-04-29 11:17:22 +02:00

Added subscriber: @bent

Bent Hillerkus commented

2019-04-29 11:17:22 +02:00

(I haven't opened & tried your file out)

That's the point of adaptive subdiv: subdivide the mesh adaptively so that there is (per default) roughly one vertex per pixel. This is useful for vertex displacements on for example terrain.
Usually setting a slider in Blender to 0 sets the behaviour to automatic or disables it. I'm not sure if this applies to this slider too, but for adaptive subsurface you wouldn't want to use that slider anyways to control the quality.

So - it's not a bug, you just assumed the feature does something different than what you've expected it to do (what did you expect?).

(I haven't opened & tried your file out) That's the point of adaptive subdiv: subdivide the mesh adaptively so that there is (per default) roughly one vertex per pixel. This is useful for vertex displacements on for example terrain. Usually setting a slider in Blender to 0 sets the behaviour to automatic or disables it. I'm not sure if this applies to this slider too, but for adaptive subsurface you wouldn't want to use that slider anyways to control the quality. So - it's not a bug, you just assumed the feature does something different than what you've expected it to do (what did you expect?).

Sebastian Parborg commented

2019-04-29 13:01:08 +02:00

Added subscriber: @ZedDB

Sebastian Parborg commented

2019-04-29 13:01:08 +02:00

Changed status from 'Open' to: 'Archived'

Sebastian Parborg closed this issue

2019-04-29 13:01:08 +02:00

Sebastian Parborg self-assigned this 2019-04-29 13:01:08 +02:00

Sebastian Parborg commented

2019-04-29 13:01:08 +02:00

As stated, not a bug.

Matthew Vanscoy commented

2019-04-29 22:20:55 +02:00

Well i set max sub divs to 0, the. I set the dicing scale to 8 (same as preview), and it still comsumed up to 16gb on avg, do i just need to reduce everything more or what?

Sebastian Parborg commented

2019-04-30 10:17:08 +02:00

If you are trying to use it on a somewhat high poly character model, you are going to have a bad time.

The ideal use case is for terrain where the base terrain mesh only consists of a very small amount of quads.
The more quads the base mesh is, the higher the memory consumption will be and it will also be slower.

If you are trying to use it on a somewhat high poly character model, you are going to have a bad time. The ideal use case is for terrain where the base terrain mesh only consists of a very small amount of quads. The more quads the base mesh is, the higher the memory consumption will be and it will also be slower.

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Cycles experimental mode causing extreme memory consumpstion and long render times with adaptive subdiv #63972