Jeff01 opened this issue on Feb 01, 2005 ยท 10 posts
Jeff01 posted Tue, 01 February 2005 at 11:20 AM
In the reflection, Firefly appears to ignore smooth polygons. Firefly also appears to try to do something in the displaced region, but not the right thing. The speckling near where the ball meets the square goes away by scaling everything up, but not these other symptoms.
Ideas?
SamTherapy posted Tue, 01 February 2005 at 12:12 PM
It certainly doesn't reflect displacement. Never experienced a problem with smooth polys, though that may be more to do with the fact that the reflections I've had were of fairly high poly objects.
Coppula eam se non posit acceptera jocularum.
face_off posted Tue, 01 February 2005 at 3:33 PM
I've seen the "won't reflect displacement" error b4. Have you tried scaling the scene by 10 or 100? May help.
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SamTherapy posted Tue, 01 February 2005 at 3:35 PM
"Have you tried scaling the scene by 10 or 100? May help." "The speckling near where the ball meets the square goes away by scaling everything up, but not these other symptoms." I'll take a guess at yes, he has.
Coppula eam se non posit acceptera jocularum.
williamsheil posted Tue, 01 February 2005 at 3:37 PM
The answer on both counts is no. Firefly uses the Reyes renderer subpixel polygon subdivision method which has a lot of advantages over mesh subdivision techniques (such as detail) but doesn't (and isn't intended to) work in raytracing. There was a long investigation thread in the now defunct beta forum last year. Prior to SR3 Poser attempted to emulate displacement by moving mesh vertices, but often gave wildly unpredictable results and CL replaced it with bump mapped reflections in that SR. It would be possible to use volumentric calculations to give displacement in raytracing, but the raytracer would need to treat every polygon in the scene as a volume and that would have a major impact on the render times of Poser scenes. Bill
williamsheil posted Tue, 01 February 2005 at 3:40 PM
On second thoughts, and looking at the picture its possible that CL haven't replaced the vertex displacement scheme with bump mapping and what you are seeing is in fact the "wildly unpredictable results" that I mentioned. Which version of Poser are you using, BTW? Bill
Jeff01 posted Tue, 01 February 2005 at 4:17 PM
face_off, yes I tried scaling up. Bill, I'm using windows P5 SR 4.1 (5.0.4.325). Thanks for your explanation. This sounds, sadly, like a limitation. Jeff
williamsheil posted Tue, 01 February 2005 at 4:52 PM
My bad for assuming that they had actually changed the functionality.
The picture above (SR4.1 again) is a reproduction of some of the ones that I put in the beta forum thread.
The ball on the left is a standard Poser ball with a noise node attached to the displacement channel and Displaceemnt value 5. Rendered using the scanline Reyes algorithms.
On the left is that same prop reflected in a mirror using Firefly's raytracer. The effect is due to the fact the mesh vertices are being displaced in an attampt to emulate the scanline displacement.
Unfortunately as the mesh density is much lower than the detail in the noise pattern, the effect is the random clumpiness.
Bear in mind that the displacement algorithms were really developed by Pixar to enhance surface texturing, not to create modelling detail. It is a bonus that in scanline rendering displacement can be used to enhance geometry, but (not to look a gift horse in the mouth) this unexpected bonus only goes so far.
Bill
Message edited on: 02/01/2005 16:54
flyerx posted Tue, 01 February 2005 at 7:40 PM
Attached Link: http://user.txcyber.com/~sgalls/index.htm
You could use PoseRay to subdivide and displace the model there and reimport it into Poser. http://user.txcyber.com/~sgalls/index.htm check out PoseRay's manual for more info.Little_Dragon posted Tue, 01 February 2005 at 7:56 PM
More things to watch out for with raytraced reflections, I suppose.
For Poser 6, I do hope CL has fixed the reflection culling bug that occurs when shadow maps are enabled.