I have this exterior scene that, with added landscaping, is taking ages to generate the light cache. I’ve tried the foliage as both normal and as vray proxies and it’s the same deal. RAM usage shoots up, and it sits on Building Light Cache. Should I be using brute force as secondary in this case?
If you are using the light cache only for secondary bounces, you could try brute force as well and see how it compares. Other than that, you could try to increase the dynamic memory limit option in the system rollout and see if it helps.
Best regards,
Vlado
Dynamic memory is already at 7000mb (max2009, 64bit) 
I turned off the foliage layers and it was fast as hell, i’ll try to narrow it down.
Wow, it’s not the foliage at all - it’s some other object somewhere. I seperated the general landscaping layer up into foliage and “stuff”. With just foliage it’s fine, but with stuff on, the light cache stalls. In fact it’s going very fast considering all the foliage. I shall continue the investigation!
I isolated it to a single object. That object was using an architectural material. Unfortunately I couldn’t replicate the stall in a fresh scene by merging/xref’ing in that object alone. As soon as I changed that material assignment everything was good!
Makes me think it would be good if vray flagged up a warning if certain “incompatible” materials are found in the scene.
materials
I think if you read your vray box it does tell you when you have an incapables material. If you convert your scene to a v-ray materials scene would that satisfy all the material issues?
V-Ray does print out warnings of you use Raytrace or Architectural materials, so you can take a look at the V-Ray messages window to see if there is anything there.
Best regards,
Vlado