Making RT ignore updates to a certain object

[Art48]

I got a pretty heavy (already optimized) scene with 2 objects which have 400k faces combined.
I don't have the option of further reducing polycount in this case. I want to develop a lava-like shader on another object (simple plane) but I need the surroundings to judge scale and integration.
Is it possible to tell VRayRT to ignore updates to those 2 heavy objects (they wouldn't be touched by me anyways) and basically not recompile them everytime I change some other geometry or stuff in the scene, making it more fluid to work with?

[matanov]

RT CPU - render your image and load it for a VFB background image, then exclude the high poly objects with Render Mask.

RT GPU - you can try making the high polys dynamic geometry (VRay object properties) and everything else static geometry, in theory (if I'm not very wrong) if you make changes only to the static geometry, the dynamic shouldn't be exported every time.

[Art48]

Thanks for your reply, the workaround with the background image is okay for now I think, but not optimal.

Not optimal because the shader on the lowpoly plane will affect reflections in the highpoly object and these reflections contribute much to the feeling of the final image and I would love to be able to see them.

A "cache" checkbox would be really cool I think per object which is turned off by default.
I would then check it and RT will only update this geometry once I stop RT and start it again (not pause, really close VFB and reopening).
If you think about implementing this, a message in the log indicating cached objects would be good since you could forget that you turned it on and wonder about the behaviour then ^^