Unity vs 3Ds Max - Render times and noise Tweet

[MikeGardiner]

Hi Otoy,

I'm trying to understand why I'm getting a difference in noise levels and render times between 3Ds Max and Unity.

I have a simple scene in Unity that I exported to 3Ds Max (using Unity's new FBX tools in 2017.2). In both programs I did the following:

1) Create a simple Glossy material using default settings and applied to all objects
2) Have a single light as daylight (in Unity this is a single direction light, in 3Ds Max it is an Octane Daylight)
3) Create 2 strip lights in the scene (in Unity this is 2 objects with a black body emitter material, in 3Ds Max it is 2 Octane lights)
4) Both are set up as Path Tracing, with identical settings on both the kernel and imager / camera

They both look very similar (a slight colour mismatch but this might be due to Unity using the lighting settings for sky light, and I can't find the corresponding setting in 3Ds Max).

However... there is a significant difference in render time and noise levels.

3Ds Max - 3:03
Unity - 6:12

And, the noise levels in Unity are significantly higher - so longer render times, and more noise.

Can you advise if there's anything I might have missed that could explain this? I'm hoping there is a setting somewhere I've missed, or if there's a Unity overhead that is a known problem? Maybe an emitting mesh in Unity renders slower than a native Octane light in 3Ds Max?

Thanks

[paride4331]

Hi MikeMikeGardiner,
could you share both scenes you did?
Regards
Paride

[Goldorak]

Hi Otoy,

I'm trying to understand why I'm getting a difference in noise levels and render times between 3Ds Max and Unity.

I have a simple scene in Unity that I exported to 3Ds Max (using Unity's new FBX tools in 2017.2). In both programs I did the following:

1) Create a simple Glossy material using default settings and applied to all objects
2) Have a single light as daylight (in Unity this is a single direction light, in 3Ds Max it is an Octane Daylight)
3) Create 2 strip lights in the scene (in Unity this is 2 objects with a black body emitter material, in 3Ds Max it is 2 Octane lights)
4) Both are set up as Path Tracing, with identical settings on both the kernel and imager / camera

They both look very similar (a slight colour mismatch but this might be due to Unity using the lighting settings for sky light, and I can't find the corresponding setting in 3Ds Max).

However... there is a significant difference in render time and noise levels.

3Ds Max - 3:03
Unity - 6:12

And, the noise levels in Unity are significantly higher - so longer render times, and more noise.

Can you advise if there's anything I might have missed that could explain this? I'm hoping there is a setting somewhere I've missed, or if there's a Unity overhead that is a known problem? Maybe an emitting mesh in Unity renders slower than a native Octane light in 3Ds Max?

Thanks

Export ORBX from Unity and try it standalone. I believe 3.07 max plugin supports importing ORBX proxy too.

[paride4331]

Hi MikeMikeGardiner,
I suppose, about this time difference, it could be you are using Unity Octane SDK TIR1 (1GPU limit).
About noise, the geometry you used with black body instead of 3dsMax Octane Lights could be the reason.
Regards
Paride

[MikeGardiner]

Hi Paride4331, I'll have to check and see if I can upload the files themselves - they are from a client project.

I switched off the emitting lights in both scenes and left only the daylight in, and the time and noise difference was still significant, so I don't believe the lights are the problem. I'm also performing the tests using a single GPU laptop so that's not the issue - I have a subscription to OctaneRender Studio anyway, so it would leverage 2 GPUs if I had them.

I'll try the ORBX test today and update with the results - thanks Goldorak.

[MikeGardiner]

Okay thanks everyone for the replies, I have conducted more tests and the error persists in Unity when using geometry. This is what I did:

Setup Scene

3Ds Max scene, with 1 Octane Daylight. Glossy material on everything. Rendered in 2:43. I exported both an ORBX and an FBX from 3Ds Max.

Unity Scene 1 - ORBX

New scene, import ORBX and place camera & light to match 3ds Max. Use EXACT Octane render settings from 3Ds Max. Rendered in 3:03.

Unity Scene 2 - Geometry

New scene, import FBX and place camera and light to match 3Ds Max. Apply a Glossy material to everything using PBR Override. Use EXACT Octane render settings from 3Ds Max. Rendered in 5:04.

In both instances, the image quality is the same, so it appears that the noise issue was eliminated. However, as you can see the render times are significantly higher when using geometry and not an ORBX. We are trying to avoid the need to go back into 3Ds Max for any reason, so this decrease in performance defeats the purpose of using Octane inside Unity at all.

I'd love for someone to help me figure out where the additional performance overhead is coming from when using geometry.

Thanks

[MikeGardiner]

Okay, another update...

I went back into the 3Ds Max file and combined all geometry into one object. I exported this as a new FBX file and imported into Unity.

It was beyond the 65k threshold so Unity split it into 2 objects, but even then Octane rendered it in 3:09.

This indicates the issue is with multiple objects in the scene - for reference, our scene only had 106 gameobjects so not a huge amount, and slightly worrying. Is there anything inside Octane that would be causing this?

[adamnerva]

The render times for the docking bay example scene seem way beyond what should be normal for that scene. Is there a way to export the docking bay scene from Unity and test it in standalone?

[Goldorak]

To confirm are you testing with more than 1 GPU in Unity? (which is the limit in the free version without having octane studio/creator license)

[adamnerva]

To confirm are you testing with more than 1 GPU in Unity? (which is the limit in the free version without having octane studio/creator license)

My hardware setup is an alienware laptop with an internal GTX 1080, and an external GTX 1080 Ti in a thunderbolt enclosure. The Octane plugin for Unity sees the external GPU as GPU 0 and so it is enabled by default when plugged in. I have tested the docking bay scene with both internal and external, and my reaction was "wow, um, 2 hours per frame? this is not the octane I remember." Also, I think showing off a scene like this to realtime guys that takes 2 hours to render, is going to turn people away. Real-time renderers excel at scenes like this one, and I'm pretty confident I could convert all the materials to realtime PBR and end up with a scene that renders with Unity's native engine and looks just as good. It's a cool scene, and I'm not trashing on it, but these kind of set pieces just look so amazing in realtime at 30fps instead of .5/hr. A couple things that might be effecting the render times with that docking bay scene are the emissive lights are all brighter than the sun, creating insane amounts of noise everywhere that takes hours to resolve, and the scale is kind of weird. The droids guarding the ship are like 10M tall. I have a feeling that cutting the emissive values all the way down 1 or below, and instead adjusting ISO/exposure would cut the render time in half. Maybe I will test that.