Planar reflection probe not rendering HDRP image effects

[nasos_333]

Hi,

I try to put the volume with my custom image effects to the reflection probe (define the layer that my volume object has) and define the main camera that shows the effects as anchor, but not get them in the reflections.

Am i missing something ?

Thanks in advance

[Bordeaux_Fox]

Check custom frame settings for reflection probe features.

[nasos_333]

@Bordeaux_Fox

Check custom frame settings for reflection probe features.

Thanks, will check it out asap

[nasos_333]

@Bordeaux_Fox

Check custom frame settings for reflection probe features.

I checked and indeed there is custom options, but in all reflection probe options the post process seem to be disabled for selection, so cant be enabled for any of the reflection modes and probes.

Is there something i am missing ? Thanks again

[Remy_Unity]

Look at the Default Frame Settings for the reflection probes : Redirecting to latest version of com.unity.render-pipelines.high-definition

But are you REALLY sure that having the post processes applied to the reflections is what you want ?
For exemple, if you have a color grading, that means it will be applied twice when looking at the reflection : once to capture the reflection, and once again when it is rendered on screen through the main camera.

[nasos_333]

@Remy_Unity

Look at the Default Frame Settings for the reflection probes : https://docs.unity3d.com/Packages/com.unity.render-pipelines.high-definition@7.5/manual/Frame-Settings.html

But are you REALLY sure that having the post processes applied to the reflections is what you want ?
For exemple, if you have a color grading, that means it will be applied twice when looking at the reflection : once to capture the reflection, and once again when it is rendered on screen through the main camera.

Hi, thanks for the heads up.

I have looked in the frame settings in both default for both reflections (baked and real time) and in the planar reflecrion probe itself (enable with checkbox) and in all cases the post process and custom post process are not available to tick and enable. Is there some other settings i should enable first ?

Also tested in both unity 2019.4.5 and 2021.2 with HDRP 10.2 and is same result.

Thanks in advance for any insight on this.

I have a custom HDRP image effect (volume clouds, photos above) that i want to be reflected in water and ideally control it resolution independetly (so i dont mind actual objects on scene, just need the volume effect rendered with the probe camera), is there a way also to make my own refection camera like i did in URP by forcing a manual 2ond camera render ?

EDIT:

I just restarted Unity 2019.4.5f1 and now seems i can change the settings and add the Post effect pass, but still i cant see my clouds effect rendered in the probe. In my Unity 2021 test i still not see the options available, i think is some setting i changed though in the HDRP settings, but not sure which might be or if is just something else.

[nasos_333]

@Remy_Unity

Look at the Default Frame Settings for the reflection probes : https://docs.unity3d.com/Packages/com.unity.render-pipelines.high-definition@7.5/manual/Frame-Settings.html

But are you REALLY sure that having the post processes applied to the reflections is what you want ?
For exemple, if you have a color grading, that means it will be applied twice when looking at the reflection : once to capture the reflection, and once again when it is rendered on screen through the main camera.

EDIT 2:

I added Bloom also to the scene and I also cant see it in the reflections, so seem all effects are ignored and not only custom made ones.

I post images for my setup, i have put the camera in anchor, the same layer in the probe as the volume component and set the custom properties of the probe camera.

Also for sure some effects make sense to be reflected, e.g. this example of Bloom above is clearly wrong in the reflection, destroying any belief in the graphics, it cant glow in the object and not in the reflection, same goes with clouds etc

[SebLagarde]

Hi. Sorry haven’t read the whole thread, just a quick notice. Planar reflection and reflection probe don’t support postprocess. So nothing will be exectuded including custom postprocess.

What miss is that we should have greyed the settings for those case.

[nasos_333]

@SebLagarde

Hi. Sorry haven’t read the whole thread, just a quick notice. Planar reflection and reflection probe don’t support postprocess. So nothing will be exectuded including custom postprocess.

What miss is that we should have greyed the settings for those case.

Oh, i see, so is there any way to reflect a post effect in water in hdrp ? I need clouds reflected in water mostly, which need to be blended with the scene objects to look correct.

In urp i just use a planar reflection script, is this possible in hdrp or something similar ?

Note that in unity 2021 the option is greyed out, so you do have this correct way there.

Also is there in roadmap to add the option later ? In the documentation is implied that post effect can be used with the probe as well, so might want to edit this as well to clarify.

Thanks

[Stardog]

Three years later this is still busted? We obviously need a reflection of what the scene looks like, not what it looks like without post/fog.

And no reflection bounces… Built-in has about 6.

When will this be added? Or does literally nobody use HDRP?

[Remy_Unity]

@Stardog

Three years later this is still busted? We obviously need a reflection of what the scene looks like, not what it looks like without post/fog.

And no reflection bounces… Built-in has about 6.

When will this be added? Or does literally nobody use HDRP?

The reflections should already have fog, but they should not contain post processing, else you would end up stacking the post processing effect (in the reflection + in the final render) leading to inconsistent results.

Are you seeing anything that you think should not happen in your case ?

[mgeorgedeveloper1]

@Remy_Unity

The reflections should already have fog, but they should not contain post processing, else you would end up stacking the post processing effect (in the reflection + in the final render) leading to inconsistent results.

I think this depends on the post process effect - for example somewhere above in this thread you make the good point that you wouldn’t want to apply color grading twice. But people do other kinds of things with post process, for example, HBAO (asset store) is a screen space occlusion effect implemented as post process. In an ideal world, this effect will be rendered by a reflection probe or planar reflection, because it can’t really be correctly applied to the reflection in the final image. Or the custom clouds above being another example. Would be great if HDRP could selectively apply post processing if it is explicitly enabled for a particular effect when rendering reflection probe etc.

[Stardog]

@Remy_Unity

The reflections should already have fog, but they should not contain post processing, else you would end up stacking the post processing effect (in the reflection + in the final render) leading to inconsistent results.

Are you seeing anything that you think should not happen in your case ?

I don’t get what you mean by stacking. We just need a bake of what the scene looks like from the camera’s point-of-view. This is all I want:

Incorrect - Built-in Unity 2020:

Correct - ReflectorProbe:

Compared:

https://github.com/LightStriker/ReflectorProbe

This allows you to plug in a camera with post effect on it, to give your reflection special looks.

Another advantage of using a custom camera is the ability to hook custom sky that another camera is seeing.

https://discussions.unity.com/t/692010/5

Doing tests… And getting full post-process on a reflection probe is actually very cool. Example, you’re underwater and have a nice color correction to make everything bit blueish. But your probe doesn’t have that, so they aren’t tinted properly. Or you have some bright light sources that don’t “glow” properly in the reflection.

And also, do you know Metallica Indirect Fallback doesn’t really work, for the most part? Most things will still be black unless you adjust sky ambient. It doesn’t act like a diffuse color. I don’t even know how you’d make a metallic scene in HDRP. And it has been years without anyone noticing…

[Remy_Unity]

I’m having mitigated feelings about your screenshots.
Take this one for example :

@Stardog

According to you the right probe is the “correct” one. But for me, it is way to bright, just look at the grass on the bottom of the sphere, that is brighter in the reflection than the one on the ground. This is what I meant by “stacking”, the bloom/exposure/tonemap is applied once when the probe is rendered, and once again when the reflection if viewed by the camera, resulting a way to bright object.
In that sense, the left probe is more correct.
But the left probe is lacking the sky, maybe this is due to some incorrect environment setting in the lighting window?

@Stardog

You may also notice that here the spheres reflected on the left probe are black. This is because reflections probes don’t capture reflection probes when baking (interreflection). You can however enable this behaviour in the HDRP global settings :

You can then re-bake the reflection probes as many times as you need bounces.

@mgeorgedeveloper1

for example, HBAO (asset store) is a screen space occlusion effect implemented as post process

And this is an error, any form of AO should not be a post process, but integrated in the render loop. If you look at this graph you’ll see that AO is done very early in the rendering process, and is actually used to light the objects, not as a simple darkening post effect.

[Stardog]

@Remy_Unity

According to you the right probe is the “correct” one. But for me, it is way to bright, just look at the grass on the bottom of the sphere, that is brighter in the reflection than the one on the ground. This is what I meant by “stacking”, the bloom/exposure/tonemap is applied once when the probe is rendered, and once again when the reflection if viewed by the camera, resulting a way to bright object.
In that sense, the left probe is more correct.
But the left probe is lacking the sky, maybe this is due to some incorrect environment setting in the lighting window

This was an old 2020 built-in project. I don’t think there is a way to capture a custom sky. For the brightness I can put the Intensity down to 0.8.

@Remy_Unity

You may also notice that here the spheres reflected on the left probe are black. This is because reflections probes don’t capture reflection probes when baking (interreflection). You can however enable this behaviour in the HDRP global settings :

You can then re-bake the reflection probes as many times as you need bounces.

For HDRP 2022.3 I need a Realtime reflection probe, which just shows black metals without Metallic Indirect checked. I tested Baked just now but have this error.

It does capture fog, you are correct.

I don’t get why it can’t just do bounces. It’s a Realtime probe, but it’s not running every frame, so performance should not be a problem.

Also, while you are here ;), please make the volumetric light multiplier an unlimited number field, and change the algorithm to remove the dot/halo when putting it high with a 500 fog distance. We just want a light shaft, not a foggy scene…

[mgeorgedeveloper1]

@Remy_Unity

And this is an error, any form of AO should not be a post process, but integrated in the render loop. If you look at this graph you’ll see that AO is done very early in the rendering process, and is actually used to light the objects, not as a simple darkening post effect.

I agree on this - the AO cannot correctly occlude only ambient light when done at a late injection point. For example, it will even darken emissive surfaces in occluded areas, which is wrong. But I was just trying to give an example of a post effect that must be stacked (applied in the probe rendering + applied in the main buffer). I also agree that most post effects should not stack, and indeed in the example the grass on the right is way too bright probably due to this.

[Remy_Unity]

@Stardog

For HDRP 2022.3 I need a Realtime reflection probe, which just shows black metals without Metallic Indirect checked

Did you try to enable “Lighting/Reflection Probe” in the Realtime Reflection frame settings? Either by overriding the frame settings of the probe itself, or in the HDRP global settings.

@Stardog

Also, while you are here ;), please make the volumetric light multiplier an unlimited number field, and change the algorithm to remove the dot/halo when putting it high with a 500 fog distance. We just want a light shaft, not a foggy scene…

Light shafts and fog (or, any atmospheric particles) are tightly bound together. HDRP is build from the ground up for realism, so if you want light shafts without volumetric fog, you will need to come with a custom implementation.

[mgeorgedeveloper1]

@Remy_Unity

Light shafts and fog (or, any atmospheric particles) are tightly bound together. HDRP is build from the ground up for realism, so if you want light shafts without volumetric fog, you will need to come with a custom implementation.

Yes I agree for pure artistic light shafts (especially if you want many of them), you’re better off finding something on the asset store. Nevertheless, with the correct settings in HDRP, you can get some pretty serious light shafts like god rays from the sun/moon, without the scene looking foggy everywhere. Anisotropy and some other settings give good results.