Accurate Raytracer
Full-scene raytracing means reflections and refractions are supported
Accurate raytracer is an alternative to fast raytracer which is geared towards a more general use. Unlike fast raytracer, accurate raytracer doesn't use any image-based optimizations and thus tends to be slower and less robust. However, it does allow full-scene raytracing meaning that reflections, refraction, and any other ray operations that interact with external objects are permitted. Like the fast raytracer it uses a BSP to divide the hair up into manageable pieces so many of the options are similar. However accurate ray tracer also provides some memory-management options, and it doesn't do internal self-shadowing. That means that you will need to use deep shadow maps or raytraced shadows to do light occlusion.
User has to resort to external shadows for self-occlusion
Unlike fast raytracer, accurate raytracer doesn't do any pre-computing before render begins. It divides its BSP tree dynamically, while rendering. Multi-processor optimizations allow multiple nodes to be divided at once for quick light tracing. Addition memory management options allow these nodes to be collapsed dynamically when they've been inactive for some period of time. This saves memory, but you would have to pay a time penalty for extra memory operations.
Parameters
Many of the parameters used by this component are same as fast raytracer parameters. You can use that help for reference.
- Auto-collapse nodes
If used nodes are collapsed dynamically if they're not used for a specified number of cycles. This can keep the memory usage constant in large scenes. With this option on accurate raytracer usually uses the least memory when compared to other Ox raytracers, as well as external (MR, Vray, geo) ways of rendering. - Collapse interval
Every N cycles all nodes will be checked for inactivity. This option specifies the N part. - Node timeout
If a certain node hasn't been raytraced for this period of cycles it (and all of its siblings) is collapsed.