Android (Oculus Quest) Virtual Reality and OBI Fluid

[MonologicGames]

Hello,

Demo scene work fine but after I connect VR headset the fluid is not visible anymore.

Any help?

Best Regards,
Damian

[josemendez]

Hello,

Demo scene work fine but after I connect VR headset the fluid is not visible anymore.

Any help?

Best Regards,
Damian

Hi Damian,

How's your VR cam set up? Obi Fluid does not support single-pass stereo rendering as described in the FAQ:
http://obi.virtualmethodstudio.com/faq.html

Does it support VR (Virtual Reality)?

Cloth, Rope and Softbodies support VR. For Obi Fluid, you will have to use separate cameras for each eye since the renderer does not support single-pass stereo rendering.

[MonologicGames]

Thats it! Thank you. But as is in desctription - [b]Please note that fluid simulation is a very demanding task. Be aware of its performance implications before using it.[/b]

We got 30fps on Oculus Quest on demo scene  Thank you for your time

[josemendez]

Thats it! Thank you. But as is in desctription - [b]Please note that fluid simulation is a very demanding task. Be aware of its performance implications before using it.[/b]

We got 30fps on Oculus Quest on demo scene  Thank you for your time

Proper fluid simulation is *really expensive*, this is something I can't stress enough and that I preach anytime I can. Should be used with care, and you should have at least some basic intuition of what's doing under the hood to be able to use it effectively.  This being said, there's lots of parameters that affect performance:

- Timestep settings.
- Fluid resolution.
- Amount of density constraint iterations.
- Amount of substeps.
- Fluid smoothing radius.
- Rendering downsampling.

Tweaking these can make a world of difference. Most of the sample scenes are meant to be run in a desktop computer. Quest is considerably less powerful hardware, comparatively closer to a mobile device. Depending on what your needs are and what you're doing in your scene, there might be a lot of room for improvement. If you give me more information about your goals, I believe I can help .

let me know how it goes! cheers,

[Odito]

Hi!

 I just bought OBI fluid this week-end and i can't figure out how to render the whisky into "whisky bottle scene" .

Through few forums and documentation, i saw that multipass should be enabled which was already the case.

I'm using Oculus Quest 2 in a URP project in Unity.

In the console, i got an error:

''The referenced script (Obi.BurstColliderWorld) on this Behaviour is missing!
The referenced script on this Behaviour (Game Object 'BurstCollisionWorld') is missing!''

This script is there but not ''accessible''.

When i open it in visual studio, it asks me to normalize the end of the code for windows (CR LF), Mac or Unix and when i chose windows it doesn't change anything..

Some idea to help me on that?

Sorry for my english and i must say i 'm new in developement  .. perhaps i missed something obvious ..

[josemendez]

Hi!

 I just bought OBI fluid this week-end and i can't figure out how to render the whisky into "whisky bottle scene" .

Through few forums and documentation, i saw that multipass should be enabled which was already the case.

Hi there!

Not just multipass, but separate cameras for each eye with a fluid renderer in each. See:
http://obi.virtualmethodstudio.com/faq.html

Does it support VR (Virtual Reality)?

Cloth, Rope and Softbodies support VR. For Obi Fluid, you will have to use separate cameras for each eye since the renderer does not support single-pass stereo rendering.

In the console, i got an error:

''The referenced script (Obi.BurstColliderWorld) on this Behaviour is missing!
The referenced script on this Behaviour (Game Object 'BurstCollisionWorld') is missing!''
This script is there but not ''accessible''.

This just means the Burst backend is not properly installed / not installed at all. Follow the setup instructions in the manual:
http://obi.virtualmethodstudio.com/manua...setup.html
http://obi.virtualmethodstudio.com/manua...kends.html

Before you go any further, you should install the package dependencies for the Burst backend (see the backends page for details), which is is the core physics engine used by Obi.

Sorry for my english and i must say i 'm new in developement.

Your english is fine, don't worry! english isn't my native language either. If you're new in development, maybe fluid simulation in VR is not the way to get started... Fluid simulation is an *extremely* advanced topic, and coupled with VR rendering it gets even harder. Chances are you'll get frustrated quickly, my advice would be to start with something simpler 

[EvanGrahamn]

Hey Damian! Sorry to hear that you're having trouble with your demo scene in VR. There might be an issue with the headset connection. Have you tried disconnecting and reconnecting the headset to see if that resolves the issue?

If you're interested in AR/VR/ML software development and want to learn more about it, check out exposit.com. They have some great resources and solutions for ar vr ml software development that could help you troubleshoot the issue you're experiencing. Good luck, and I hope you can get your demo scene up and running in VR again soon!

[ImpossibleRob]

Is this something on the roadmap to support single-pass rendering? This would potentially alleviate some of the performance problems on Quest which is also my target device. Single-pass is IMO mandatory for Quest VR since all other means are performance-prohibitive.

[josemendez]

Is this something on the roadmap to support single-pass rendering? This would potentially alleviate some of the performance problems on Quest which is also my target device. Single-pass is IMO mandatory for Quest VR since all other means are performance-prohibitive.

Unfortunately screen-space ellipsoid splatting (the rendering method used by Obi) and single-pass stereo rendering just don't mix, so this isn't something that will eventually get done.

There's a good chance we will add compute-based marching cubes or surface nets as an alternative rendering method in the future, which will allow for single-pass stereo at some extra GPU cost. I don't have an ETA for this, though.

kind regards,

[PixaPatrick]

Hi, I just purchased Obi Fluid and didn't realize there were issues with VR as I've used Obi Ropes before in VR. 

I have rendering set to multipass, I'm using the OVRCameraRig from Oculus, and I have it set to use a camera for each eye. I have an Obi Fluid Renderer on each eye, but I still can not see the fluid in the sample scenes. I'm using the Faucet scene and I can only see the shadow of he water. I can not see the water itself. 

Is there anything that I am missing?

Best,
Patrick