Practical use of Render Elements

[ArsDeco]

Hello everyone,

while i have a basic grasp of Render Elements, I am still confused how some of them can be used most efficiently. It would be great if you could share some insight into this issue.

The passes I have issues with are:

VrayRawReflection & VRayReflection filter
I though multipling these two would yield a result equivalent to VRayReflection - This is not the case if using 16bit tif/tga files and Photoshop. Am I doing something wrong or should these passes be used differently?

VrayRawRefraction & VRayRefraction filter
same as above.

VRayUnclamped colour
is this the unclamped version of the VRayDiffuseFilter pass? To my mind I either work with 16bit+ (then the image will contain unclamped values) or i render everything as 8bit, then the colours in this pas will be clamped as well.

VRaySampleRate
how is this pass usually utilized?

VRayRawTotalLighting
the manual states that TotalLighting is obtained by adding the Lighting, GI and Caustics passes. is this the Raw counterpart of this?

VRayIlluminance
again how is this pass used most efficiently?

Regards.

[rivoli]

VrayRawReflection & VRayReflection filter
I though multipling these two would yield a result equivalent to VRayReflection - This is not the case if using 16bit tif/tga files and Photoshop. Am I doing something wrong or should these passes be used differently?

when working with elements, if you want correct and consistent results, you have to work linearly from the beginning to the end. that means rendering in linear space with no colour mapping, save outputs in hdr and comp in 32bit. it's likely the inconsistencies you're having are coming from comping 16bit files.

VRayUnclamped colour
is this the unclamped version of the VRayDiffuseFilter pass? To my mind I either work with 16bit+ (then the image will contain unclamped values) or i render everything as 8bit, then the colours in this pas will be clamped as well.

actually the files will be clamped in 16bit colour depth too.

VRaySampleRate
how is this pass usually utilized?

I use it as a kind of diagnostic tool. it's quite handy to check if the sampling is performed efficiently, you can find out if you're oversampling or downsampling renders.

VRayRawTotalLighting
the manual states that TotalLighting is obtained by adding the Lighting, GI and Caustics passes. is this the Raw counterpart of this?

I guess it is, yes. even though I usually don't use raw elements, I have enough control in post even with the already filtered ones. but I guess if you really need yo break a render to pieces and sort of rebuild it from scratch than raw elements are what you need.

[Dave_Wortley]

VRayRawTotalLighting
the manual states that TotalLighting is obtained by adding the Lighting, GI and Caustics passes. is this the Raw counterpart of this?

The VRayRawTotalLighting is the RawLighting + RawGI + Caustics
The VrayTotalLighting is the the (RawLighting + Raw GI + Caustics)*Diffusefilter

It's important to understand why you have to use 16bit files for lighting passes even if you're working in 8bit workflow. To be able to blow out the lighting, the multiplication function needs values higher than 1 which you will only get with a 16bit file.

[Dave_Wortley]

The better way to work tho is to do
((RawLighting*Diffusefilter) + (RawGI*Diffusefilter))

Does anyone know how you're supposed to use the shadow render element pass in comp, we've got a subtle difference that i'm having a look at seeing if we can match...

[gagui]

Does anyone know how you're supposed to use the shadow render element pass in comp, we've got a subtle difference that i'm having a look at seeing if we can match...

Good question, anyone?

[Dave_Wortley]

Apparently the raw files aren't totally accurate... according to the vray guys who were here yesterday.