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.

[Alejandro Testa]

Roy, one question,  is better to draw slabs with thickness instead of extruded solids to avoid  light leaks with this version?

Regards,

Alejandro

[Roy Hirshkowitz]

It doesn't matter.  You need to avoid 3dface type objects-- thin objects -- particularly when these occur at a boundary between inside and outside.

[Marc Chaumier]

And to simulate the glass of windows, could we use 3DFaces? As the light have to pass through the material...

[Roy Hirshkowitz]

Yes-- just make sure it's tagged as Thin.

[qweqwi]

more quality ..but more slower...in the beginning...

[Alejandro Testa]

Roy, I am trying to load any of the new engines and I d´ont found any lsp command. Where is located? or I am doing something wrong?

[Roy Hirshkowitz]

(nxtengine 2)

At the command prompt.  nXt must be loaded first.

[Jan Verzelen]

should we turn the path tracer on or off or will that make no difference

[Roy Hirshkowitz]

It doesn't matter.  Checking or unchecking the box will set either engine 0 or engine 1-- leave it alone if you want to try the new stuff.  (nXtEngine) all by itself will tell you what the current engine is.

[Roy Hirshkowitz]

I just found a problem w/ Engine 2-- I'll upload the fix this evening.  It's working much better on exteriors now.

[Roy Hirshkowitz]

Okay-- it's fixed and uploaded.  If you've grabbed 291 go back to the well and get the current one (292.)

[Rey F. Rosario Berrios]

Do not found the 292