vrayReflection Render Element problem

[OPEN_RANGE]

I am saving a .exr with 3 render elements included. Denoiser, vraySpecular and vrayReflection. I open th eextr in photoshop with exr-IO and the elements are there as layers. I change the specular and reflection layer blending modes to ADD and adjust opacity to suite.. I've done this on a number of other renderings with no trouble. For some reason on this rendering the reflection element seems almost inverted and it just doesn't work.

https://forums.chaosgroup.com/forum/...9958-120-n-fir

Not sure what I may have done to cause this. Has anyone experienced this? Any advice or help much apreciated.

[glorybound]

For the first time in a decade, I cut/paste my exterior glass reflections (fake it). Since NEXT my glass is just black and my reflection element pass is also black. I have been bringing this up for a year, however, I have never gotten an answer, except, V-Ray is doing things now as other render engines do it. Something about the reflection pass being included in the specular pass. Maybe you can get an answer.

[OPEN_RANGE]

Here are some screen grabs showing how the vrayReflection render element does not seem to be working properly. I'm sure I have used it in the same way, with my current setup and versions of software and not had this trouble. You can see in the photoshop layers palette what is on and the associate blending modes. specular render element works as expected. reflection render element..not.

[glorybound]

Yep, that's how mine is looking since V-Ray NEXT. VrayRawReflection sometimes helps.

[OPEN_RANGE]

thanks for confirming the problem is not just with me. that's helpful for sure.

[fixeighted]

If you render passes for: Bkg, Lighting, GI, Reflection, Refraction and specular you should have what you need. Layer them in that order from Bkg up to Specular and ADD all = win....

[OPEN_RANGE]

Thank you for your reply. I understand which elements, what order and the layer blending mode. The problem is that the vrayReflection render element does not seem to be getting generated correctly.

Bobby ( glorybound) confirms has the same experience/ problem in his reply above.

Is this a bug?

[fixeighted]

Hmm....I tested this this morning just to be sure. I output exactly those layers and achieved the exact same result as the beauty.
What precisely are you aiming to achieve, just so I completely get the issue?
Is it a literal separation of e.g. every part of the reflection in a window in order to control it's effect?
If so, then this definitely works but you need more layers than just the 3 you mentioned, as the reflection is split between the specular and the reflection pass. Also the refraction element will have its contribution.

[OPEN_RANGE]

Hi fixeighted and thanks for helping with this. What I'm trying to achieve is what I have beciome accustomed to acheiving in the past with the basic render element setup, same as you describe.

See the 4 images in my post above. Unfortunatley they are inserted in the ideal order and I can't change that. Goign form left to right consider them image1 thru image4. Take special note of the pshop layers palette on the left of each image. It shows which layers are visible in each image. It does not show it, my bad, but the blending mode for each render element layer is set to ADD.

Image1 - specular element only. notice how thumbnail in layers palette appears mosttly black

Image3 specular element over RGBeffects layer works as expected.

Image4 - reflection element only. notice how thumbnail appears mostly white

Image2 - reflection element over RGBeffects layer does not work as expected or as it has in my past experience.

So, not sure if I have something configured wrong of if this is a legitimate bug type of issue. Bobbby, above, has the same trouble.

I hope this makes things more clear, it is often difficult to describe and document this type of stuff via forum posts.

Thanks again for checking into this and for your input.

[fixeighted]

Possibly something is weird if you are using the denoised beauty pass and then comping stuff on top. The denoised 'effects result' pass has all the reflections in it, no?
The way I mentioned is a more suitable way of doing it and allows you the control you are looking for. Of course if you want to denoise the render then you can still use the denoise version, with just the windows masked with the corrections you choose.
Try the test with just the elemnts I noted and you should see an immediate result - no real reason why not, as we are presumably on the same versions of vray NEXT and Max isn't doing anything weird at your end.

I agree that your elements look a bit odd, as I would expect there to be lots more relective parts in your scene. But that may be down to materials' reflectivity of course.
You're welcome to pack up an extremely stripped scene with just the lighting, walls and windows and I'll have a look. It's another day off for me and I'm bored, so it's no trouble at all

[fixeighted]

Here is a vey quick test comp with the necessary bits to achieve this one thing, i.e. altering the reflection on just the windows. It has the layers suggested with all else that was in the exr deleted, apart from the cryptomatte for the windows only, so that can quickly isolate them.
I'm sure you already know all this but I needed to know that you're seeing the same sort of things on your side and this can relate appropriately. I hope it helps.
https://www.dropbox.com/s/3ex0w0eq9n...PTEST.psd?dl=0

[kosso_olli]

From the V-Ray Next Help docs, regarding the reflection elements behaviour. This has all been well documented before, I wonder why this still comes up.

"Since V-Ray Next Update 1, some of the render elements are rendered differently than before. The Lighting render element now contains all direct diffuse illumination and the GI element contains all indirect diffuse illumination. Similarly, all direct reflections of lights now go to the Specular element and all indirect reflections go to the Reflection element.

Previously this behavior depended on the sampling of the lights and not just on the type of the contribution. Some of the direct contributions that should be in the Lighting and Specular elements were written to the GI and Reflection elements instead. In both cases they compose back to Beauty correctly but the different types of contributions are now split between the elements more consistently. This change makes the elements more consistent but it's also needed for preventing artifacts in these elements with the adaptive dome light (and possibly in the future with other adaptive lights).
The raw elements are affected only when the corresponding normal and filter elements are available, otherwise they're rendered as before. This is because the raw elements have to be derived internally from the corresponding normal elements in order to work with the consistent elements (f.e. VRayRawGlobalIllumination = VRayGlobalIllumination / DiffuseFilter).
There's an option to enable or disable the new behavior in the Global Switches rollout under the V-Ray tab in the Render Setup window. The consistent elements are automatically enabled when the scene contains an adaptive dome light so they don't have artifacts. They are also enabled by default for new scenes. For V-Ray GPU they are always enabled without an option to disable them."

[OPEN_RANGE]

fixeighted - thanks for that. your .psd file has the reflection element I am used to getting generated. Now I get something much different. I was using the reflection and specular elements ABOVE the rgb effects layer. Decrease opacity of those reflect and specular elements to a small value and play with that to "boosts" the reflections and highlights if desired.

I think the difference is as stated by Oliver in his post above. Are you using vray Next update 1 or more recent? If not than yo are still getting the reflection element rendered the old way, which is what I was used to.

Oliver - Thanks you that's very helpful. The technical details are somewhat beyond my level of expertise and knowledge but I think I understand the gist of what you describe. I guess I will try using the vray RawReflection element and see if that works for me. Disabling the new/default behavior in the global switches seems less desirable. Plus, if I understand correctly, if I use an adaptive dome light with hdri, then the new behavior is implemented regardless/automatically.

Thanks again for your help. I did read the docs as a first step but d d not find that info you reference.

[fixeighted]

I am using version 2.1 (4.20.01.00001).

If you are doing something other than what I had set up then the result will be different but I can't assess what exactly, as I don't have your file/setup images. You would need to re-render the image with those specific elements in order to troubleshoot anything I'm afraid.
Please try that and report back
It really does work as expected, as you can see from the psd I linked, so I'm unsure why your example (or Glorybound's) is seemingly so different. If what you see in my reflection element is what you are used to seeing then you simply must have something set up a little wrongly.
Forgetting Photoshop, I'd suggest investigating the reflection passes in the Vray frame buffer to try to isolate the issue.
As Kosso said, the reflections are part of both the reflection element and that of the specular, so you really do need both outputs, plus the other comp layers in order to achieve what you want.
I hope all this helps

Also, of course, feel free to say that I am completely wrong

[glorybound]

The problem isn't reassembling elements to recreate the beauty pass. I don't have any doubt that works. The problem is that the reflection pass doesn't have any reflections. The RGB doesn't have glass reflections for my exteriors and to try to boost it with the reflection pass doesn't work because that too doesn't have reflections.