New Build (304)

[Roy Hirshkowitz]

Path Tracer Problem

Fixed a problem in which a complex object (one which generates a lot of faces at render time) tagged as a light source can slow the path tracer down substantially.  This slowdown is also observed in the new engines, although not to the same degree. 

AutoCAD ACA 2013 - Known limitation

The standard ACA mechanism for assigning materials to sub-components is not working properly in 2013.  I am actively pursuing a solution to this, including attempting to communicate with Autodesk.  Until this is fixed, avoid using ACA 2013 with nXt if you use ACA objects (walls, windows, etc.).  Other AutoCAD objects, including native AutoCAD objects and custom objects appear to function fine in 2013.

Work continues on engine 4.  This build includes fixing a few crash bugs and resource leaks.  Color backgrounds are now supported.  Alpha objects are supported, although shadows will not be retained in this engine.

[Marc Chaumier]

I'm colour-blind, so I call sometimes my wife for colors advices. And my comment was about to say that one looks more natural than the other... The judge, in last is the eye, I believe... And I was talking about the 303.

You're right, my job is to give better pictures... Natural, accurate... Sometimes, a lie says more truth than an accuracy ;D

Roy Hirshkowitz said:

I can appreciate that you (and your wife) might prefer e1-- but my job is to make the simulation more accurate-- not to make the picture better (that's your job.) 

[Marc Chaumier]

George, yes, I prefer the E4, but if I have not enough time, the result is better with E1. When you can let it cook long time, so the picture with the E4 is much better.

Roy, I let a little space between the paving stone of the balcony and the frosted glass, so I believed that it was an problem with the curve. Keep on this way, Roy, the 304 was a good improvement of the E4, which is really attractive. I send you the dwg.

[Roy Hirshkowitz]

It's not a mirror, BTW.  It's a picture with a plate of glass over it.  A true mirror would be easy to resolve.  The glass probably isn't reflecting more than 10% of the light it receives, and any light that makes it all the way to the surface of the picture is, in effect, a double caustic (it must pass first through the window of the room, then through the glass of the picture.)  

Similar, perhaps more troubling things, are happening in the plates and mugs.  These materials are only partially reflective.  They are having trouble completely resolving.  These types of materials are scheduled for another look.

This is a more difficult scene, BTW, than George's window and tea party, and not just because of the materials.  Zooming in on a corner of a larger space with many openings makes things take longer if the scene contains objects which reflect the entire space.

This one looked pretty good at about 45 minutes on my machine (I wouldn't hesitate to show it to clients despite the remaining noise.)  Getting rid of the last of the noise with e4 is a colossal pain in the butt-- and something I'm working on (but not sure yet if there's anything I can do.)

Garret Diduck said:

That is looking much better with more passes. Besides the mirror not resolving, there are still fireflies on the mug as well. My concern is that, while the overall image is quite good, the render will need to cook a lot longer (than the PT) to get the fireflies to resolve enough to make the image acceptable to a client. To get, say, 15000 passes would take quite awhile to resolve and even then, the image may still have fireflies. 

[Roy Hirshkowitz]

Made a few changes to try to reduce the fireflies-- 1/2 hr. 300k pixels, original file.  Second image has daylighting channel turned off.

[Roy Hirshkowitz]

This is one of Peter's office drawings-- so he's got nine large diffusers on the ceiling which might represent flush mounted fluorescent luminaires.  Pretty boring, flat light, for a home (but typical for an office.)  You can see the reflection of the diffusers in the glass vase.   I think the simulation is good.  I'm not really trying to get great images here-- mostly just looking at the convergence characteristics of the engine.