GPU renders have warmer colors than CPU renders. #47812

New Issue

Mike · 2016-03-16T01:41:35+01:00

Mike commented

2016-03-16 01:41:35 +01:00

System Information
2013 MacPro 8-core, 64GB RAM
Titan X

Blender Version
2.77 rc2

I also noticed that rendering this fire on the GPU in 2.77 has a different color tint than the CPU renders in 2.77 or other versions. The colors are slightly warmer/more yellow on the GPU renders in 2.77. Our renderfarm is a mix of CPUs and GPUs so this would be a problem for us, making a large portion of our renderfarm useless if we have to choose GPU rendering or CPU rendering to ensure the look is consistent. Ive attached 3 frames, with the middle frame (#623) being the one rendered by the GPU.

SANCT_XX - Flyover AoS_0622.png

SANCT_XX - Flyover AoS_0624.png

SANCT_XX - Flyover AoS_0623.png

**System Information** 2013 MacPro 8-core, 64GB RAM Titan X **Blender Version** 2.77 rc2 I also noticed that rendering this fire on the GPU in 2.77 has a different color tint than the CPU renders in 2.77 or other versions. The colors are slightly warmer/more yellow on the GPU renders in 2.77. Our renderfarm is a mix of CPUs and GPUs so this would be a problem for us, making a large portion of our renderfarm useless if we have to choose GPU rendering or CPU rendering to ensure the look is consistent. Ive attached 3 frames, with the middle frame (#623) being the one rendered by the GPU. [SANCT_XX - Flyover AoS_0622.png](https://archive.blender.org/developer/F293135/SANCT_XX_-_Flyover_AoS_0622.png) [SANCT_XX - Flyover AoS_0624.png](https://archive.blender.org/developer/F293137/SANCT_XX_-_Flyover_AoS_0624.png) [SANCT_XX - Flyover AoS_0623.png](https://archive.blender.org/developer/F293136/SANCT_XX_-_Flyover_AoS_0623.png)

Mike commented

2016-03-16 01:41:35 +01:00

Changed status to: 'Open'

Mike self-assigned this 2016-03-16 01:41:35 +01:00

Mike commented

2016-03-16 01:41:35 +01:00

Added subscriber: @LMProductions-1

Thomas Dinges commented

2016-03-16 16:29:53 +01:00

Added subscriber: @ThomasDinges

Thomas Dinges commented

2016-03-16 16:29:53 +01:00

Please attach a blend file demonstrating the issue, as clearly asked for in the bug report guidelines! Also it would be more helpful to have the same frame number from CPU and GPU, this way we can directly compare the image.

Mike commented

2016-03-16 17:02:21 +01:00

Sorry. I thought maybe you guys would've heard of this before and therefore might be able to explain it from just the images. Ive attached the .blend file.

I will also attach a .png of frame 623 rendered with the CPU when its done rendering.

Thanks for the help!

SANCT_XX - Flyover AoS.blend

Sorry. I thought maybe you guys would've heard of this before and therefore might be able to explain it from just the images. Ive attached the .blend file. I will also attach a .png of frame 623 rendered with the CPU when its done rendering. Thanks for the help! [SANCT_XX - Flyover AoS.blend](https://archive.blender.org/developer/F294238/SANCT_XX_-_Flyover_AoS.blend)

Mike commented

2016-03-17 16:58:12 +01:00

Here is the rendered CPU image of frame 623.623 (CPU render in 2.77).png

Here is the rendered CPU image of frame 623.[623 (CPU render in 2.77).png](https://archive.blender.org/developer/F294467/623__CPU_render_in_2.77_.png)

Mike commented

2016-03-18 01:31:51 +01:00

Any thoughts after seeing the .blend or the images Thomas?

Mike was unassigned by Aaron Carlisle

2016-03-20 19:24:43 +01:00

Mike commented

2016-03-21 17:33:54 +01:00

I see this case is assigned to "none" and priority is "incomplete." Is this bug submission a lost cause?

Wolfgang Faehnle commented

2016-03-21 20:09:19 +01:00

Added subscriber: @mib2berlin

Wolfgang Faehnle commented

2016-03-21 20:09:19 +01:00

Hi Mike, I take the freedom and edit your file to get it better handled on slow connections and so.
The color error ist still visible but render now much faster to check.
Can you please check on the file?
Btw., the image ashes.jpg is missing in your .blend but does not really matter.

SANCT_XX - Flyover AoS_edit.blend

The switch to "Incomplete" was before you add your file, an admin has to change back.

I can verify the color difference between GPU and CPU.

Blender 2.77
Opensuse Leap 42.1 x86_64
Intel i5 3570K
GTX 760 4 GB /Display card
GTX 670 2 GB
Driver 361.28

Mib

Hi Mike, I take the freedom and edit your file to get it better handled on slow connections and so. The color error ist still visible but render now much faster to check. Can you please check on the file? Btw., the image ashes.jpg is missing in your .blend but does not really matter. [SANCT_XX - Flyover AoS_edit.blend](https://archive.blender.org/developer/F297656/SANCT_XX_-_Flyover_AoS_edit.blend) The switch to "Incomplete" was before you add your file, an admin has to change back. I can verify the color difference between GPU and CPU. Blender 2.77 Opensuse Leap 42.1 x86_64 Intel i5 3570K GTX 760 4 GB /Display card GTX 670 2 GB Driver 361.28 Mib

Thomas Dinges commented

2016-03-21 20:14:34 +01:00

We get a lot of reports every day. We try to handle them quickly, but sometimes it just takes time. Please have some patience. ;)

Mike commented

2016-03-21 21:52:16 +01:00

In #47812#365240, @mib2berlin wrote:
Hi Mike, I take the freedom and edit your file to get it better handled on slow connections and so.
The color error ist still visible but render now much faster to check.
Can you please check on the file?
Btw., the image ashes.jpg is missing in your .blend but does not really matter.

SANCT_XX - Flyover AoS_edit.blend

The switch to "Incomplete" was before you add your file, an admin has to change back.

I can verify the color difference between GPU and CPU.

Blender 2.77
Opensuse Leap 42.1 x86_64
Intel i5 3570K
GTX 760 4 GB /Display card
GTX 670 2 GB
Driver 361.28

Mib

Thanks Wolfgang. I'm not sure what you did to try to make it faster aside from removing the grate on the model? I rendered your .blend on my CPU at 100 samples as you had it, and it took 1min and 12 seconds. On the GPU it took 7mins and 21 seconds. So 7x slower on the GPU still.

> In #47812#365240, @mib2berlin wrote: > Hi Mike, I take the freedom and edit your file to get it better handled on slow connections and so. > The color error ist still visible but render now much faster to check. > Can you please check on the file? > Btw., the image ashes.jpg is missing in your .blend but does not really matter. > > [SANCT_XX - Flyover AoS_edit.blend](https://archive.blender.org/developer/F297656/SANCT_XX_-_Flyover_AoS_edit.blend) > > The switch to "Incomplete" was before you add your file, an admin has to change back. > > I can verify the color difference between GPU and CPU. > > Blender 2.77 > Opensuse Leap 42.1 x86_64 > Intel i5 3570K > GTX 760 4 GB /Display card > GTX 670 2 GB > Driver 361.28 > > Mib Thanks Wolfgang. I'm not sure what you did to try to make it faster aside from removing the grate on the model? I rendered your .blend on my CPU at 100 samples as you had it, and it took 1min and 12 seconds. On the GPU it took 7mins and 21 seconds. So 7x slower on the GPU still.

Wolfgang Faehnle commented

2016-03-22 08:08:19 +01:00

Hi, just for info, alongside Samples and Dimension I change Step Size to 0.5 in Volume Sampling (Please check 0.5 - 2).
I remove objects/meshes not involved in render time/color error to shrink size of .blend to 1/3 of original file.

Mib

Hi, just for info, alongside Samples and Dimension I change Step Size to 0.5 in Volume Sampling (Please check 0.5 - 2). I remove objects/meshes not involved in render time/color error to shrink size of .blend to 1/3 of original file. Mib

Mike commented

2016-04-12 22:14:35 +02:00

I see there has been no activity here for awhile. Just dropping this post to keep the issue fresh. I know a lot of bugs get submitted every day. I did a render last night of a scene with a fire & smoke, and the smoke is a different color on each frame rendered with the GPUs than with the CPUs.

Im using 2.77a now. Issue persists.

I see there has been no activity here for awhile. Just dropping this post to keep the issue fresh. I know a lot of bugs get submitted every day. I did a render last night of a scene with a fire & smoke, and the smoke is a different color on each frame rendered with the GPUs than with the CPUs. Im using 2.77a now. Issue persists.

Sergey Sharybin commented

2016-04-19 17:21:39 +02:00

Added subscriber: @Sergey

Sergey Sharybin commented

2016-04-19 17:21:39 +02:00

Can see the issue with the new file now. Will investigate.

Sergey Sharybin self-assigned this 2016-04-19 17:21:46 +02:00

mathieu menuet commented

2016-04-19 18:53:55 +02:00

Added subscriber: @bliblubli

mathieu menuet commented

2016-04-19 18:53:55 +02:00

Not sure this is related, but in some of my test, NVidia and AMD gave different results regarding max bounces. It looked like NVidia did trigger the russian roulette much faster than AMD (AMD renders where exactly like the CPU ones). Nvidia did some driver side optimisation for Luxmark, so it may be the same for Cycles. So the bug may not be on Blender's side.

blender-admin commented

2016-04-20 12:29:08 +02:00

This issue was referenced by 4cdd6b9bdd

This issue was referenced by 4cdd6b9bddac37d8a482cbf44cf4c94fb4d10135

Sergey Sharybin commented

2016-04-20 12:49:31 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2016-04-20 12:49:31 +02:00

Mike commented

2016-04-21 01:38:37 +02:00

I see this issue is marked "resolved" "by committing 4cdd6b9bdd: Fix #47812: GPU renders have warmer colors than CPU renders"

Does that mean the issue is fixed? If so will it be in the next release?

Thanks! =)

I see this issue is marked "resolved" "by committing 4cdd6b9bdd: Fix #47812: GPU renders have warmer colors than CPU renders" Does that mean the issue is fixed? If so will it be in the next release? Thanks! =)

Thomas Dinges commented

2016-04-21 01:51:15 +02:00

The fix will be in tomorrows daily build (builder.blender.org) and in the next official release.

blender-admin commented

2016-05-08 14:54:11 +02:00

This issue was referenced by blender/cycles@7111ce6b61

This issue was referenced by blender/cycles@7111ce6b611e962f0c66655fdb13c58df496d70b

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GPU renders have warmer colors than CPU renders. #47812