Here is a selection of nodes that doesn't work the same as in EEVEE and CYCLES:
TextureCoordinate Node, "object"
- seems to be world coordinates and don't use object transforms
Vector Transform Node is missing
- Would be good for converting object to world and world to object
- scaling seems to be reverese in regards to what EEVEE uses (i.e 0.5 -> 2.0)
Image Texture node
- BOX mapping reverts back to FLAT (and seems like that for other projections as well)
The Principled BSDF Shader has an option to enable Subsurface however these options now produce a totally black preview render and no final render at all. Please see my separate bug report linked below.
The [Clamp] checkbox produces a black preview render and no final render.
The [Overlay] mode appears to do nothing.
The [Soft Light] mode appears to do nothing.
The [Linear Light] mode appears to do nothing.
The [Hue] mode appears to do nothing.
The [Saturation] mode appears to do nothing.
The [Lighten] mode appears to do nothing.
The [Screen] mode appears to do nothing.
The [Dodge] mode appears to do nothing.
The [Burn] mode appears to do nothing.
All of the above modes produce a white output / nothing at all when two simple colours are applied.
At least my testing skills match the code
The other modes do appear to do something. Further testing required.
It is also to be noted that the [Mix and Multiply] options will render correctly in the interactive preview (dark but correct) but they do not render the same result in Final Render. Only one of the MixRGV inputs is taken - Color1. Even with a 0.5 factor.
I tried to use a setup where I project an enviroment texture from a reference point onto geometry. It works fine in EEVEE and CYCLES but fails in RPR
1 Geometry Node is completely missing
2 Unclear if Math nodes work (Have not tested separately at this time)
3 Enviroment Texture node is completely missing so no way to sample panoramas or env. captures
4 Unclear if values in Value node is used (Have not tested separately at this time)
What OS are you guys in? I can't even get ProRender to install for 2.8. It says it installs, but it shows up nowhere and I can't find the addon anywhere in my directory structure.
I'm in Win 7 Pro 64-bit.
Most of us are either MacOS or Windows 10 but you shouldn't have a problem in Windows 7 (I have this right now, at the office, and it works).
Once you've installed the plugin if it doesn't show up in the Add-ons panel either, what you can try is go to C:\Program Files\AMD\RadeonProRenderPlugins\Blender and manually add the plugin to Blender. Although I've installed multiple times and it works just fine. If it does appear in the Addons panel, you might have a conflicting install with 2.79b, it does happen sometimes.
AHA!!! That did it.
Why it doesn't simply install it in the correct spot in the first place is .... silly.
Thank you for your help. NOW I can finally mess around with this. I can't get it to work in 2.79 either, I get some errors when trying to enable it. But at least it installs in the correct location LOL. I'm assuming that's because I'm using the most recent build of 2.79 (and 2.8 for that matter)
Anyhow .... Now to go learn 2.8 so I can learn and use ProRender.
Adding a Bright / Contrast node causes the RPR preview render to go black and the final render to not begin. Nothing happens. Removing the B/C node allows the render to continue working again.