Clarisse:
i am mind blowed how good this softwhere is.. The tank it self loaded to clarisse takes just 400mb. In Houdini 5gigs and in blender 9gigs. Not only that.. with all the grass and trees with no alpha where each leaf is 300 vert model (same with grass). i was blown away all displayed in viewport and smooth.. And ram usage was at 2GB at that moment including 500mb VDBs from houdini to make fog. So i was like, ok let's push this, instead of doing dirt texture on wheels i just scattered 4 milion spheres with displacment for each wheel. + grass. and it was like adding cube to the sceen. At that moment i knew it gona be fun. The rock was build by pushing displacement to 20M polygon. and scattering 35 milion of little strands of moss.
Houdini: was used for simulation of long grass on grill of tank and procedural, nature assets (moss,grass,leafs)
Assets from internet (wood).
System ram usage at peak rendering was 5GB.
Special thx to Dez, Captain LeBuck, Jerry.