obi fluid + hdrp

[locque]

This would be amazing, the fluid shader looks so good that it really deserves to be viewed in an HDRP environment.

I would be happy to provide testing and feedback for an experimental build as as soon as possible.

[fluidman84]

This would be amazing, the fluid shader looks so good that it really deserves to be viewed in an HDRP environment.

I would be happy to provide testing and feedback for an experimental build as as soon as possible.

At this point even some simple HDRP shader that is visible would be better than nothing. Obi particle behavior is better than all other fluid systems currently available. It doesn't need to be perfect, but at it's current state nothing can be seen in HDRP which doesn't even allow a use case.

[josemendez]

At this point even some simple HDRP shader that is visible would be better than nothing. Obi particle behavior is better than all other fluid systems currently available. It doesn't need to be perfect, but at it's current state nothing can be seen in HDRP which doesn't even allow a use case.

It's being worked on. The reason it hasn't been released yet is that the entire render workflow of all Obi assets is being rewritten for Obi 7. Instead of doubling the amount of work (make a HDRP renderer for the current framework, then immediately throw it in the bin and start re-doing it from scratch), we're writing it directly for the new one.

Some background info on why things are being re-done: Obi 7 includes a compute-shader based physics backend (which for Obi fluid, allows to simulate +60000 particles in under 4 ms/frame on a modern GPU). The thing about GPU physics is that passing any data back to the CPU stalls it, this has such a negative impact on performance that it often negates any benefits of using the GPU at all.

To render stuff using the current framework, we need to have the particle data on the CPU. The only way to do this when using the GPU to simulate physics is to bring back data asynchronously, but this means you trade speed for latency: the data you get is several frames old, which is not acceptable (don't want to render what happened 5 frames ago, but what happened in the current frame!).

So all data must remain on the GPU. This means meshes must be built directly on the GPU without particle data ever setting foot on the CPU. And this of course means we have to ditch the current rendering framework and rewrite all rendering components in Obi.

Good news:
- this benefits all assets and all backends, both from a workflow and a performance standpoint.
- I've been at it for several months now, so it's in a very advanced state. Videos soon.

[locque]

Wow that sounds amazing, can't wait to try out Obi 7! Thanks for all your hard work and great support, you're a very inspiring developer



One more thing I wanted to add to the HDRP discussion is that its not just about getting nicer materials and lighting. For me it's all about getting access to TAA which is absolutely crucial for visual quality in VR. The HDRP TAA is so good that it's actually comparable to 150-200% supersampling at close to no performance impact. There is some ghosting of course, but it is very tolerable compared to either a massive performance cost with supersampling or really nasty specular aliasing with mulitsampling and FXAA/SMAA.

Without HDRP support, to my knowledge there is simply no way to get TAA with Obi in VR.

The postprocessing package for the builtin RP does have stereoscopic TAA in theory, but it is completely broken in multi pass mode which is needed for Obi. It gives a taste of how great it could look on left eye, but the right eye is full of horrible artifacts and afterimages. This was reported almost a year ago and still hasn't been fixed, if it ever gets a fix it's probably not anytime soon.

The URP doesn't have any official TAA, there is only a paid third party TAA asset. It actually looks pretty good and is more customizable than the builtin RP or HDRP TAA, but unfortunately has no stereoscopic support at all.

[LiquidOwl]

Hi,
Thank you for this great plugins, firstly!
Any news about hdrp?
Thanks in advance!