Help How to render transparent and opaque fluid particles with URP

[Mich279]

The last project that I used obi fluid for was a couple of years ago and I was just using the built in renderer. It was easy to separate the different renderer components on the main camera and have different renderer setting for different emitters. I had some emitters simulating water with transparent particles and other emitters simulating a foam like liquid with opaque particles.

I am now working on a new project with some friends of mine and we are using the URP. Iv got the renderer stuff set up in the URP settings but cant seem to figure out how to render some emitters with transparent water like particles and other emitters with opaque coloured particles.

I read another forum post in which in the response it was confirmed that "It’s not possible in URP to have different emitters using different fluid rendering properties, since the URP pipeline is an asset, and assets in Unity cannot have references to objects in the scene." (http://obi.virtualmethodstudio.com/forum...hlight=URP)

I can't seem to figure out how to use the URP and render both transparent and opaque coloured particles from different emitters in the same scene. I would very much appreciate any help from the community and the developers on this matter. 

Thank you in advance.

[josemendez]

The last project that I used obi fluid for was a couple of years ago and I was just using the built in renderer. It was easy to separate the different renderer components on the main camera and have different renderer setting for different emitters. I had some emitters simulating water with transparent particles and other emitters simulating a foam like liquid with opaque particles.

I am now working on a new project with some friends of mine and we are using the URP. Iv got the renderer stuff set up in the URP settings but cant seem to figure out how to render some emitters with transparent water like particles and other emitters with opaque coloured particles.

I read another forum post in which in the response it was confirmed that "It’s not possible in URP to have different emitters using different fluid rendering properties, since the URP pipeline is an asset, and assets in Unity cannot have references to objects in the scene." (http://obi.virtualmethodstudio.com/forum...hlight=URP)

I can't seem to figure out how to use the URP and render both transparent and opaque coloured particles from different emitters in the same scene. I would very much appreciate any help from the community and the developers on this matter. 

Thank you in advance.

Hi,

This is not possible, and an inherent limitation of how renderer features work in URP.
In the future, we want to work around this by ceasing to use renderer features and instead write a custom renderer for URP.

Kind regards,

[Mich279]

Hello, 

Thank you for the quick response. I was worried that would be the answer.

I was wondering whether there is a work around with the shader that the Obi Particle Renderer component uses. I played about with switching between shaders that came with Obi and the ParticleShaderURP has a different result compared to the normal ParticleShader. Attached in an image of what I mean.  (left is default ParticleShader, right is ParticleShaderURP)
   

Is it possible to copy the shader and manipulate it to render a specific emitter particles to be opaque?

Or is the current answer simply just to use the built in render?

Thanks again in advance.

[PureSpark]

Hi,

This is not possible, and an inherent limitation of how renderer features work in URP.
In the future, we want to work around this by ceasing to use renderer features and instead write a custom renderer for URP.

Kind regards,

Hi. 

Has this issue for URP been resolved yet? In my project the settings of the Fluid Renderer component on the camera have no effect. Can even remove if off the camera because in URP it seems to provide no purpose.

[PureSpark]

Hi. 

Has this issue for URP been resolved yet? In my project the settings of the Fluid Renderer component on the camera have no effect. Can even remove if off the camera because in URP it seems to provide no purpose.

Bump

[josemendez]

Bump

Hi there,

The ObiFluidRenderer component in the camera is intended for the built-in pipeline only. In URP, rendering is performed by the FluidRenderer feature in your URP renderer. See:

http://obi.virtualmethodstudio.com/manua...ering.html

Setting up fluid rendering is done in a slightly different way depending on which scriptable render pipeline you're using. Note the HDRP rendering pipeline is not currently supported:

Built-in:Add a ObiFluidRenderer component to each camera you need to be able to render fluid.
Universal (URP):Add a ObiFluidRendererFeature to the feature list of your pipeline's Renderer asset, see the following picture.

Because of limitations in URP's renderer feature system, it is currently not possible to have multiple fluid renderers rendering specific emitters in the same scene.

kind regards,

[PureSpark]

Hi there,

The ObiFluidRenderer component in the camera is intended for the built-in pipeline only. In URP, rendering is performed by the FluidRenderer feature in your URP renderer. See:

http://obi.virtualmethodstudio.com/manua...ering.html


Because of limitations in URP's renderer feature system, it is currently not possible to have multiple fluid renderers rendering specific emitters in the same scene.

kind regards,

Thanks, but you mentioned this in your response 6 months ago.

"In the future, we want to work around this by ceasing to use renderer features and instead write a custom renderer for URP."

So it is possible? Is there an ETA?

[josemendez]

Thanks, but you mentioned this in your response 6 months ago.

"In the future, we want to work around this by ceasing to use renderer features and instead write a custom renderer for URP."

So it is possible? Is there an ETA?

Hi,

Obi 7 (which is currently undergoing beta) allows for this, by using rendering passes. These are scriptable objects that relate specific fluid emitters to specific fluid renderer features. This allows you to have multiple renderer features in URP, each one rendering a specific subset of emitters in the scene. See:
http://obi.virtualmethodstudio.com/forum...-3849.html

http://obi.virtualmethodstudio.com/manua...ering.html