I see that I'm not the only one with large scene rendering problems
Rendering was done on 4 computers ( 6core, 3.2 Ghz, 8 Gb of RAM ) As I sad it rendered frame for 10-15 mins.
This is just exterior. If you are more interested, can see complete animation (10min) on my site. Put it full screen and pump up the volume
About optimization.
As I was working on model I was reading a lot of tutorials and make my own conclusion which may help a little bit so here they are:
-64 bit system is first "must have"
-biggest problem obviously is ram memory. If you see in rendering status message "unloading geometry" than you know that you have the problem. Rendering time in that case can be 3-4 times higher then usual and rendering process become much more unstable. Solution - buy more memory or try to optimize scene.
-put windows virtual memory up to initial 15 Gb. From my experience vray will crash when reach current maximum (even windows will expand it) It is automated process but in that moment it looks like sometimes vray can't wait more virtual memory to became available
-no matter what convert geometry to vray proxy objects. Max have instancing geometry option but it is not close to vray proxys efficiency. It will consume much less memory. For example everything you see in this animation is converted (trees, grass, buildings, cas, almost everything) Make a test scene and save it. Then convert it to proxy and you will see that all of the geometry is there, but file (including proxys) wil be smaller up to 5-10 times.
-users usually don't look deep enough and default vray settings are not setup to handle this type of scene. Most important setup is in "vray system" settings: dynamic memory limit and default geometry. Dynamic memory is by default set to 400Mb and that is not enough. You should calculate amount of all space that vray proxys take on your hard drive and input that size. If you have a lot of memory 8-16 Gb you can try with for example 2000 Mb or so. Important is to leave (balance) some amount of memory for rendering proces. I found some free tutorial (webinar) from this site ... talking only about this settings for 1.5 hours (i have lost link but you can google it)
-get rid of all raytrace materials. They are not compatible with vray and can make artefacts and boost memory usage. Be careful to check materials of imported models.
-don't use vray frame buffer. Using Max's will also save some memory. If you can best way is to turn it off completely.It will save you some memory and can feel speed up for few %
-limit number of reflection/refraction bounces/levels to 3-4. Usually you will not see difference between 4 and 50 bounces of reflections , but it will also speed up rendeing process
-Global illumination. I always bake gi passes Here is the well known tutorial.
-And few unusual memory saving tips If you reach memory limit you can free some memory by restarting Max and sometimes Windows. Set up all scene so when is loaded you only have to press render. Believe me it helps sometimes and can free few hundred Mb of memory. Don't use viewport shading - go wireframe before saving file, especially when you have big textures. They also consume ram.
Talking about speed.
Most important settings that affect rendering time is vray image sampler. Start with something low like 2/4 and do few tests to see what are minimal max/min values for DMC sampler that will satisfy your quality standards.
This are only some ideas about you should think about and there is much more to talk about but my job is calling me.. Good luck with renderings.
