is that a call to end this discussion, AgentSmith? i hope it's not too abnormal to have disagreements online here? PJF, I meant that REAL radiosity is indeed just like real light, because it actually is real light. i didn't mean that various 3D versions of radiosity solutions were perfectly accurate. it's good that you read up on radiosity and GI, but alas reading up on them doesn't equate to having used them for years my friend. i am ignorant of nothing, and have been studying photons and photon-mapping as it were for years. you seem to think that real light acts in some mystical and unforeseeable way, my friend. that it's not caculable by mathematics, and that photons don't follow physical rules which are in fact computable. this mystical world of light seems very poetic, but doesn't reflect the reality of things at all. photon-mapping in mental ray, for example, is as accurate as you like it to be. you merely turn down the settings for previewing your scene, then crank them way up when you approach final rendering. So, for a scene with only one light such as a lamp, that bulb actually DOES emit a certain range in quantity of photons. if we say a lamp emits 1,000,000 photons per second, for example, with a jitter of maybe +/- 100,000 to account for fluctuations in power consumption, then how is this not calculable in a scene? do you think a REAL lamp is unmeasurable in those aspects? this is exactly what photon-mapping is. also, you mention that the photon map has to be combined with ray-tracing for cross-referencing? poppycock. you can turn off ray-tracing but turn on "Direct illumination shadow effects" and use ONLY photons to light a scene. NOT like real light? how so? do you think that the millions of R&D that mental images spent perfecting their software was wasted on this mystical, incalculable thing called photon-mapping? do you think for one second that Maya, XSI, 3DS, and mental ray are unable to perform this higher-level of math with great ease? photons emit, decay, bounce, refract, reflect, and carry color with them all along the way, changing wavelengths as they go. anyone who's ever seen a prism knows this. and in all your readings did you miss the part where they stated, "photon mapping is exactly what is says it is : photon mapping"? Well, now you have "read" it, an so you will know it. radiosity simluations only work backwards in Bryce. i highly suggest reading up on mental ray, everything you stated in your last post has been completely contradicted in fact and in function by this program. using Final Gather produces emission of light from any surface, based on a huge quantity of possible attributes. Image-Based Lighting is achieved this way, where the light and dark values of an image are sampled to control the radiance. when used in conjunction with photon-mapping, how is this not accurate and "like real light"? you're saying there is no spoon, because you are only using your eyes, and not your finger to touch it! and lastly, "If the pictorial results from using Bryce True Ambience (and other "quicky" workarounds of Distributed Ray Tracing that might save from "having to program anything") can be as realistic as those produced by other rendering processes, then that's fine with me." Well, to sum it up : it can't. Bryce simply can't be as realistic as the others, and can never animate those "pro-renders". not to say it doesn't have value, but what you're all trying to say here is that your '78 Ford Pinto is going to keep up with a 2006 Skyline. MY point is that you can take the Pinto to the store, on a date (what?!?), or to the movies, but you certainly can't take it to the races no matter how many "Pro-Racer" decals you slap on it.