Subdivision Modifier unusal RAM usage #72884

New Issue

Jonathan · 2020-01-03T18:13:08+01:00

Jonathan commented

2020-01-03 18:13:08 +01:00

System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.28

Blender Version
Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-12-04 11:32, hash: f1aa4d18d4
Worked: (optional)

Short description of error
Opening the attached examplefile (~60MB) with visible subdivision modifiers the used system RAM is very high (~33GB).
After rendering the used system RAM is "cleared" and the example file only uses about 800MB.

~31GB unnecessarily used RAM before hitting render.

Exact steps for others to reproduce the error

Cookies Subd visible.blend
Cookies Subd hidden.blend

Opening the attached examplefile "Cookies Subd visible.blend" (~60MB) with visible subdivision modifiers the used system RAM is very high (~33GB).
After rendering the used system RAM is "cleared" and the example file only uses about 800MB.

~31GB unnecessarily used RAM before hitting render.

File size: 61.804KB
RAM Usage after opening: ~33GB
RAM Usage initializing Render GPU(1x2080ti): ~60GB
RAM Usage while rendering: ~5GB
RAM Usage after render: ~800MB

With hidden subdivion modifier there is a expectable RAM usage (File: "Cookies Subd hidden.blend"):

File size: 61.804KB
RAM Usage after opening: ~360MB
RAM Usage initializing Render GPU(1x2080ti): ~35GB
RAM Usage while rendering: ~5GB
RAM Usage after render: ~400MB

**System Information** Operating system: Windows-10-10.0.18362 64 Bits Graphics card: GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.28 **Blender Version** Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-12-04 11:32, hash: `f1aa4d18d4` Worked: (optional) **Short description of error** Opening the attached examplefile (~60MB) with visible subdivision modifiers the used system RAM is very high (~33GB). After rendering the used system RAM is "cleared" and the example file only uses about 800MB. - >~31GB unnecessarily used RAM before hitting render. **Exact steps for others to reproduce the error** [Cookies Subd visible.blend](https://archive.blender.org/developer/F8258421/Cookies_Subd_visible.blend) [Cookies Subd hidden.blend](https://archive.blender.org/developer/F8258449/Cookies_Subd_hidden.blend) Opening the attached examplefile "Cookies Subd visible.blend" (~60MB) with visible subdivision modifiers the used system RAM is very high (~33GB). After rendering the used system RAM is "cleared" and the example file only uses about 800MB. - >~31GB unnecessarily used RAM before hitting render. File size: 61.804KB RAM Usage after opening: ~33GB RAM Usage initializing Render GPU(1x2080ti): ~60GB RAM Usage while rendering: ~5GB RAM Usage after render: ~800MB With hidden subdivion modifier there is a expectable RAM usage (File: "Cookies Subd hidden.blend"): File size: 61.804KB RAM Usage after opening: ~360MB RAM Usage initializing Render GPU(1x2080ti): ~35GB RAM Usage while rendering: ~5GB RAM Usage after render: ~400MB

Jonathan commented

2020-01-03 18:13:08 +01:00

Added subscriber: @Tschonatschan

Germano Cavalcante commented

2020-01-06 20:36:12 +01:00

Added subscribers: @Sergey, @mano-wii

Germano Cavalcante commented

2020-01-06 20:36:12 +01:00

I can't open the file on my system with 16GB of RAM.

I believe the file has very heavy settings to handle the Subdivision modifier.
If so, this is not considered a bug. The user has to be aware of the limitations when setting up a modifier.

@Sergey, if I'm not mistaken, you've worked with this modifier a few times, any idea why the memory decreases after rendering?

I can't open the file on my system with 16GB of RAM. I believe the file has very heavy settings to handle the Subdivision modifier. If so, this is not considered a bug. The user has to be aware of the limitations when setting up a modifier. @Sergey, if I'm not mistaken, you've worked with this modifier a few times, any idea why the memory decreases after rendering?

Jacques Lucke commented

2020-01-22 12:42:45 +01:00

Added subscriber: @JacquesLucke

Jacques Lucke commented

2020-01-22 12:42:45 +01:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Jacques Lucke commented

2020-01-22 12:42:45 +01:00

I can confirm that the memory usage by that file is high.
However, the file itself is unsuitable for any debugging in my system with 32 GB RAM.

@Tschonatschan, please try to simplify the file so much that the peak RAM usage is below, let's say 10gb.

I can confirm that the memory usage by that file is high. However, the file itself is unsuitable for any debugging in my system with 32 GB RAM. @Tschonatschan, please try to simplify the file so much that the peak RAM usage is below, let's say 10gb.

Jonathan commented

2020-02-03 15:48:00 +01:00

Sorry for the late response. After testing a bit I got some weird results.

The original scene consisted of 5 similar objects. To decrease peak RAM usage i deleted one after another, saved in a separate file, closed and opened fresh before hitting render. Here are the results:

5 Objects
File size 62MB

RAM usage:
open 33GB
init 61GB
render 5GB<-------- This is the really weird stat
after 800MB <-------- This is the really weird stat

4 Objects
File size 50MB

RAM usage:
open 26GB
init 56GB
render 30GB
after 26GB

3 Objects
File size 37MB

RAM usage:
open 20GB
init 41GB
render 20GB
after 20GB

2 Objects
File size 25MB

RAM usage:
open 13GB
init 29GB
render 15GB
after 13GB

1 Object
File size 13MB

RAM usage:
open 6,8GB
init 15GB
render 8GB
after 6,8GB

I tried to delete the objects in a different order, but got the same results.
The mesh is heavily subdivided, In case of the original file with 5 objects blender is fully operable with 33GB or 175MB of RAM usage, without any performance differences.
First i thought it was because I got 64GB RAM installed and it uses ssd for memory. But similar results on a 96GB RAM PC.
Any hints on how i can investigate furthermore?

Sorry for the late response. After testing a bit I got some weird results. The original scene consisted of 5 similar objects. To decrease peak RAM usage i deleted one after another, saved in a separate file, closed and opened fresh before hitting render. Here are the results: 5 Objects File size 62MB RAM usage: open 33GB init 61GB render 5GB<-------- This is the really weird stat after 800MB <-------- This is the really weird stat 4 Objects File size 50MB RAM usage: open 26GB init 56GB render 30GB after 26GB 3 Objects File size 37MB RAM usage: open 20GB init 41GB render 20GB after 20GB 2 Objects File size 25MB RAM usage: open 13GB init 29GB render 15GB after 13GB 1 Object File size 13MB RAM usage: open 6,8GB init 15GB render 8GB after 6,8GB I tried to delete the objects in a different order, but got the same results. The mesh is heavily subdivided, In case of the original file with 5 objects blender is fully operable with 33GB or 175MB of RAM usage, without any performance differences. First i thought it was because I got 64GB RAM installed and it uses ssd for memory. But similar results on a 96GB RAM PC. Any hints on how i can investigate furthermore?

Campbell Barton commented

2020-02-12 04:43:03 +01:00

Added subscriber: @ideasman42

Campbell Barton commented

2020-02-12 04:43:03 +01:00

Please provide a simplified blend file which doesn't use too much memory (10gig peak), then give exact steps to redo the problem, what happens, what you expect.

Aaron Carlisle commented

2020-02-20 05:23:36 +01:00

Added subscriber: @Blendify

Aaron Carlisle commented

2020-02-20 05:23:36 +01:00

Changed status from 'Needs User Info' to: 'Resolved'

Aaron Carlisle closed this issue

2020-02-20 05:23:36 +01:00

Aaron Carlisle self-assigned this 2020-02-20 05:23:36 +01:00

Aaron Carlisle commented

2020-02-20 05:23:36 +01:00

No activity for more than a week. As per the tracker policy we assume the issue is gone and can be closed.

Thanks again for the report. If the problem persists please open a new report with the required information.

No activity for more than a week. As per the tracker policy we assume the issue is gone and can be closed. Thanks again for the report. If the problem persists please open a new report with the required information.

Goury commented

2021-11-10 02:32:07 +01:00

Added subscriber: @Goury

Goury commented

2021-11-10 02:32:07 +01:00

Please reopen.
Blender still uses ridiculous amounts of ram for multires subdivisions for no good reason.
Bug or not, this have to be optimised.
Using a couple of terabytes(!) of ram to achieve good smooth detail is pure madness.
Yet it is how it is when it comes to a reasonably large and detailed object.

It's especially maddening when the ram required to do everything else after initial loading is around just 5-7 GB.

Please reopen. Blender still uses ridiculous amounts of ram for multires subdivisions for no good reason. Bug or not, this have to be optimised. Using a couple of terabytes(!) of ram to achieve good smooth detail is pure madness. Yet it is how it is when it comes to a reasonably large and detailed object. It's especially maddening when the ram required to do everything else after initial loading is around just 5-7 GB.

Campbell Barton commented

2021-11-10 05:03:16 +01:00

D12406 will improve memory use for the common case, I don't think it helps to keep this open unless there is a spesific case that can be identified.
Showing a complex file with high memory use isn't something we typically handle in bug reports.

[D12406](https://archive.blender.org/developer/D12406) will improve memory use for the common case, I don't think it helps to keep this open unless there is a spesific case that can be identified. Showing a complex file with high memory use isn't something we typically handle in bug reports.

Goury commented

2021-11-10 06:08:10 +01:00

okay

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Subdivision Modifier unusal RAM usage #72884