Sorry to say, but Radeon ProRender Doesn't Really Support MantaFlow.... (Infact no Render Engine does except for Blender Cycles....)
Well, Things like Externel Addon-type Render Engine (eg:- Octane, V-ray, Luxrender) doesn't seem to Support Mantaflow.... So after searching around the internet for quite some while.... It looks like currently only cycles can do the job....
Thank you for your reply! I found this article (https://80.lv/articles/radeon-prorender-2-3-for-blender-released) saying that the biggest change was the added support for the new mantaflow fluid simulation system. But can't find the reference on amd's website anymore...
Hope AMD will provide support for mantaflow soon!
Well, I looked out and after Several Tests I got It worked... It isn't as cool as it looks On cycles but RPR Works quite a bit.... While in render mode and Radeon Pro Render Selected, Bake Data of the Domain.... This Works.... (Well, I couldn't get any resource on How to Get Fire+Smoke to Work.... +RPR doesn't Work with liQuid Simulations....)
This is Kind of What it Does... (Without "Noise" Baked..) + After Some Research I Found that I think Even Before MantaFlow RPR Didn't Support FIRE+Smoke but Only the Smoke.... Still the RPR Can't do it.... I think it's all you on your CPU NOW....
Just tried it and you're right, it works! Thanks! but you can't bake noise thought... Still a major improvement from what I had previously .
I was also able to render on my GPU. See attached
I mainly want to use the smoke sim to create clouds, so this should be more than perfect!
I followed this thread with quite some interest since I'm currently evaluating RPR against Cycles.
For me Cycles renders a smoke simulation just fine. But RPR takes approx 50 seconds for a single frame only in viewport render mode. Did you also have those issues?