Just to clarify there is no 'cap' in-so-far as an expiration date on the number of polygons you are allowed: It's a "ran out of memory" issue, because renderer has to hold all of its polygons/surfaces/software/texture maps in memory to do a render, and if you have run out... you have run out. Using a bucket rendering system (like a lot of software does these days) can mitigate this issue, because it only loads in the polygons in a given 'bucket' (subdivided square of the rendering environment) this tactic can fail if you have all your detail contained within one single bucket though
LW does not have a bucket rendering solution built in. Yet...
There are a number of workarounds. Don't use Lightwave to render with. Render your object in layers (would be handy if LW had a simple layer rendering system wouldn't it!!!). Manually subdivide your screen into a number of region renders, or use
http://www.trueart.pl/?URIType=Direc.../VirtualRender which is quite cool, if a bit expensive!
Running a 64 bit system will help (assuming you are using 64 bit LW) But yes the whole point of having 64 bit LW is not because it's faster, but because it allows you to load ridiculously high poly scenes, so long as you have enough memory installed. By it's nature, LW is actually very efficient at rendering high poly scenes, and can handle a lot without resorting to bucket techniques, but you will hit a wall unless you throw ungodly amounts of ram into your system
LW can render ludicrous poly counts by using volumetric 'cheats' like HDinstance, and the new hair will probably be also able to render a ludicrous number of polygons using the same method, but there's a limit on what you can do with this method. Instancing of sections can help (as I mentioned in previous posts) as if it's re-using the same data from several angles, this is saving memory! But yes, I am not using hyperbole when i say I can't do a full station render, I physically can't!