At the same time I started modeling this car I was lucky enough to get on the beta testing team on finalRender (fR), so when I had it all modeled it was obvious to render it with fR. fR is a full-blown raytracing system for 3dsmax 4.2 with features like GI and HDRi that I used heavily in this project

If you want to know more about fR you can take a look at www.finalrender.com the maker of fR or www.trinity3d.com the distributor of fR.

This is going to be fR specific, so if you don't have fR skip this part.

The scene is one big sphere, with a plane in the bottom where the car stands. You can see this on Fig 29. I did this in order to exclude the sphere from the MSP so it didn't show up in the reflections (instead the HDR shows up). And most important to render the car from all possible angle, and still have a single colored shaded backgournd, instead of seeing the HDRi map.

Settings	Global	Local Tire	Local Ground	Local Env.
Reflection Depth	3
Refraction Depth	2
Diffuse depth	2
Prepass size	1/1
RH Rays	512		1024	1200
Balance	90
Curve balance	75
Min. Density	8	100	10
Max. Density	16	200	100
Ambient Multipliere	1
Adaptive Quality	0
Ambient rougness	15
HDRI cover angle	300
AA, Min. Samples	5
AA, Max. Samples	10

As you can see I used local density settings for the tire and ground. This mean I get more details exactly where I want it. The tires needed more dense samples because the tire is made up of small canyons, and if you have read the manual this can be a bit of a problem, but with local settings this was easily fixed. Also the ground plane got higher density and more rays, more density to catch the details between the tire and ground, and more rays to smooth out the large ground area. The big env. sphere had a higher amount of rays too, to make it smooth.

But remember density setting is scene depended so you can't transfer my settings directly to your own scene.

On Fig 30. You can see a rendering where show samples is turned on. The body of the car got some huge samples, but more details isn't needed since the car is so reflective, so even with low distribution of samples, you can't see any artifacts on the final image. The ground, env and tire got a lot more density to catch the details and smooth it out nicely.