Windshield Raytrace How?

[gaggle]

A jeep, eh.. is it's windshield flat by any chance? If there's no curvature in it, and it's a thin sheet of glass anyway, you don't have to use raytracing at all. You should be able to pull it off using a flat mirror. That is, for reflection. You don't have to refract at all if it's flat.

If raytracing it (reflection and/or refraction) really makes a difference, then try lowering the maximum bounces the rays can do. Default for MAXs built-in raytracing are 9 bounces, you can in some cases lower that to as much as 1 or 2, without much loss. Goes plenty faster then. I'm not sure how Brazil handles that, but I'm sure there's a setting somewhere in there as well.

You can go ask on their forum if you need specific Brazil help as well.

Other than that, if the windows really need the raytracing.. well, then that's just how it is. Raytracing takes time. Turn it off until the animation is completly done, and then throw plenty of processingpower at it for final rendering.

[rquinn]

thanks gaggle ill try lowering the bounces does that work for non transparent objects?

[gaggle]

Yep it works nicely. Though it's not guaranteed to increase the performance. It only helps if there are rays that are bounced around a lot in the first place, if you have a flat reflective surface, then those rays may not bounce more than once anyway, and thus lowering the maxmimum bounces won't help any. It's only when dealing with reflective surfaces that can see eachother for example (in which case the rays would be bouncing back and forth), or if rays have to pass through multiple refractive surfaces, or those kinds of situations, that you see a speedimprovement in reducing the maximum number of bounces.

Raytracing is generally considered an expensive feature to utilize. And there are many many ways to cheat. If the reflected environment doesn't change you can use a reflection map, possibly a cube map generated every 10th or 50th frame or whatnot. Or you can raytrace a simple sphere that moves where the jeep is supposed to be, then capture its surface as an animated reflectionmap, and that map on the jeep. It can work out nicely, as the time spent on raytracing only goes towards the simpler spherical shape, not the whole jeep.

Anyway, the point is there are ways to not having to use hardcore bruteforce raytracing at all. Hell, the Renderman people have lived without any sort of raytracing at all up until just recently.

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