New Build (291)

[Roy Hirshkowitz]

This one introduces two new engines.  Both of these are very experimental at the moment. I may not retain either of them if they don't prove useful.  Although they appear very stable, there may be some hidden bugs.  Be careful using these for production until we have some confidence in their stability and characteristics.  The engines are only accessible via the nXtEngine AutoLisp command use (nXtEngine 2) -OR- (nXtEngine 3).

Both engines include more light pathways than the current product does and can therefore potentially provide more accurate solutions.  Two "tricks" which are used in the first two engines, transparent shadow rays and daylight portals, are not used in these new engines.  This gets rid of two big sources of inaccuracy.  Caustics pathways are automatically included.

Engine 2 can be much less noisy than the Path Tracer for most interiors.  It's convergence, on the other hand,  is not as graceful and will include some discrete artifacts.  It's usually a lot faster than the Path Tracer for interiors.

Engine 3 is a little more accurate than Engine 2, particularly when window coverings are involved.  It converges more gracefully, but slower for some interiors.  It is considerably faster on some exteriors.

Some things to keep in mind with these engines:

• Light leaks in the corners are possible when doing interiors.  Make sure walls, floors and ceilings are modeled as slabs with thickness.
• Both engines start slowly and accelerate.  Pixels/sec should increase as they proceed.
• Using accurate IORs is very important.  IORs of 1.00 should not be used for glass.
• Designating glass as Thick/Thin is more important with these engines.
• Translucency is not implemented.  Allow Surface Roughness is.
• These engines use more memory than the previous two.  64 bit is recommended.  Start your testing and low resolutions.

Let me know what you think-- I'm looking for feedback here.

[chen ray]

hi roy i understand now there are a few engines u have developed for nxt. can advise which of the engine is more stable and have faster rendering time ?

[Roy Hirshkowitz]

Engine 2 and 3 have basically been abandoned.  I'm going to remove them soon as an option-- don't use them.  Engine 4 is most likely to be retained for the future.  It should be stable.  Whether it's faster depends a lot on your scene.  The original engine is usually the fastest.