Small terrain with VR extremely slow

[Dutchottie]

I've got a micro sized (256x256) terrain of which I've blocked a large section to prevent trees/bushes/etc to spawn.
I only need 1 position (no movement) so I can block a lot. I used the Gaia Manager to set it to XR enabled and HDRP. All seems to work.
I've use the Coniferous biome as starter and changed trees and bushes for my own (jungle style).
I've used GeNa for one simple river (baked). Please see the attached screen shots
In the runtime I only need the Lighting, Wind Zone and left the command buffer, flora global and terrain loader enabled (the rest is disabled).
On my i9, GTX3080Ti, 64GB machine with a Vive Pro running Steam and Unity 2021.3.18 the performance (in the Editor) is extremely slow. Even with slow head movements the image reverts to the Steam default before rendering the Gaia landscape again, ad infinitum.
Anyone have an idea why it is so slow? Any suggestions how to best speed up things?
 

[Bryan]

If you are making a VR title you should not be using HDRP. 
URP could be fine to use. 
Also, you need to check the requirements depending on where you plan on releasing. 
For example, if you were to release on Oculus then the requirements are the same as an android phone. 
 

[Dutchottie]

Hi,

No there will be no release. It is a project meant for internal scientific research at our labs :-). And I need the HDRP from the research perspective (mainly because of high-quality avatars).
We are using the Vive Pro headsets exclusively.

[Bryan]

Your rendering everything twice, HDRP is not recommended. 
If you want good quality I would suggest using URP.

However, the only tips I would recommend trying are: 
 

Disable Vignette : Vignette is not compatible with multi-display. It is disabled by default. You can enable it if your VR system has only one display

Disable Chromatic : Aberration Chromatic Aberration is not compatible with multi-display. It is disabled by default. You can enable it if your VR system has only one display

Disable Bloom : Bloom is not compatible with multi-display. It is disabled by default. You can enable it if your VR system has only one display

Disable HDRI Sky : HDRI Sky is not yet compatible with stereoscopy It is disabled by default. You can enable it if your VR system is not using stereoscopy

Disable Contact Shadows : Contact Shadows is not compatible with multi-display. It is disabled by default. You can enable it if your VR system has only one display

Disable Ambient Occlusion : Ambient Occlusion is not compatible with multi-display. It is disabled by default. You can enable it if your VR system has only one display

Disable Motion Blur : Motion Blur is not compatible with multi-display. It is disabled by default. You can enable it if your VR system has only one display

Disable Lens Distortion : Lens Distortion is not compatible with stereoscopy or multi-display. It is disabled by default. You can enable it if your VR system has only one display and is not using stereoscopy

Disable Screen Space Reflection : Screen Space Reflection is not compatible with multi-display. It is disabled by default. You can enable it if your VR system has only one display

Disable Screen Space Refraction : Screen Space Refraction might not be compatible with multi-display depending on conditions. It is enabled by default. You should experiment with your application

Disable Screen Space Shadows : Screen Space Shadows is not compatible with multi-display. It is disabled by default. You can enable it if your VR system has only one display

Disable Exposure : Exposure is not yet compatible with multi-display. It could be made compatible by synchronizing the exposure value on all cluster nodes. It is disabled by default. You can enable it if your VR system has only one display

Disable White Balance : White Balance is not yet compatible with multi-display. It could be made compatible by synchronizing the white value on all cluster nodes. It is disabled by default. You can enable it if your VR system has only one display

Disable Depth of Field : Depth of Field is not compatible with multi-display. It is disabled by default. You can enable it if your VR system has only one display

Change Anti-aliasing to SMAA : FastApproximateAntialiasing and TemporalAntialiasing are not compatible with multi-display. By default anti-aliasing is set to Subpixel mophological AA

Hopefully, this helps you a bit. 
Again HDRP isn't really supported for VR as of yet. 
These should help though. 

[Dutchottie]

Thanks!
Although I really don't understand. Gaia comes with both HDRP support and XR support. No mention about Gaia in HDRP not being compatible with XR. I'm confused. Plus, it's weird that I should not use HDRP when I need it (always use it on desktop systems) for my projects. Anyway.
The environment works fine. Even with most of the stuff you mention enabled. I'm using a HTC Vive Pro and as goes for most "consumer" level HMDs it uses a single display partitioned in the images. These images do generate stereoscopic view, but at still 1 display. As most HMDs use this config, I'm confused by your explanation. Does the disabling of all these post processing stuff have a real effect on these HMDs?! Sure, any process you turn of saves cycles, but they are fine compatible with most HMDs.
I've done multiple tests with Gaia in HDRP with XR. No problems. My biggest issue often is that I need too much realism (for research) and cannot get away with gaming solution too much - like trees appearing when moving or clear LOD transitions.
For this tiny environment the solution was simply in removing (blocking) the bioms spawners for all the areas that are not visible from the players fixed position.
I also replaced the PW shader with one from Natural World as it did a much better job at rendering my palm tree faithfully. Especially the high-lights were really off making the trees look like plastic.

Thanks for your replies! I do appreciate it very much even though I do not really understand why I should not use HDRP when it still works fine 🙂

Cheers!

Marco

 

[Bryan]

Hello, 

Technically you can, we did add support and you can still use it. 
I would make a build and test. 
I am curious to see how it goes for you. 
Please keep me updated.