CompuServe Thread

// Radiosity is here, its available in the software package Lightscape. This is a // realtime animation and rendering package. Animation is just a series of still // images as you know. Hi Robert, What I meant with stills was that Radiosity rendering is so time consuming that you don't have time and money to use it in an animation for a projekt. // The only version I have seen of this package was on an SGI, however, I've // heard that an NT version is in the works. I'm doing what I can to confirm this. // Radiosity based renderings may be within our reach quite soon. Sounds wonderful, P90 is not far behind SGI Indy so its about time we can do it to. Daniel

>> not commonly found in raytracers I stand corrected. Thanks John. BTW, how's it going? Over two months have passed since Siggraph, and we haven't chatted much. Last time we talked, you were looking into trying some additional software and hardware. How did all that work out? I'd love to hear your impressions of the "other" stuff. Also, tell your dad that Karen and I said "Hello". – Dave

>>Actually, radiosity rendering is not commonly found in raytracers<< Excellent point, John, and the primary reason why many of the RT scenes I have seen lately look hopelessly flat. I was recently visiting a large game company in LA, whose Mac-based 3D group were "busily" waiting around for a bunch of PowerMacs to RT 3D scenes for their games. After looking at some of the finished examples in which the foreground and backround lacked any sort of depth, I asked how many light sources were used in the scene. "Oh, we only use one light for raytracing", the art director said. "The renderer does all the work in this program, not like those nasty scanline-based renderers where you've gotta simulate ambient light all the time. And besides, the more lights you add, the longer it takes to render, you know." I just said "Uh, yeah, um, looks real nice…"<g> Poor guy had no clue. The bottom line is that, until Radiosity is a viable function for desktop systems (Next year? Tomorrow? I really don't know), part of the Art of 3D scene creation (for many of us) is gonna be creative lighting techniques that give the illusion of light and the way it disperses itself in any given situation. I'm sure you know this well from your lighting backround; how you can create depth in any scene with a nice lighting set-up. 3DS gives us many ways to simulate ambient and direct light, and therefore makes it possible to get great depth in 3D scenes with very short rendering times. And this is one of the definitions of a production-oriented system, IMHO. -Alan

>> Radiosity Thanks for the clarification. – Dave

Hello ! For what I know those fast Radiosity renderers are no more than gouraud rendering with a precalculated Radiosity applied to the Database that has been tesselated in very small poligons for that purpose. That means that the big off-line calculation is done once and after that almost every render could acomplish the task. Only a small detail… Neither lights nor objects can move. That is well suited for arquitectural render but not for common animation. if you move lights and-or objects time …. goes really high. That Gouraud rendering is done in near-real-time with SGI hardware but could be pretty fast with 3D Studio.

You can get RayMan from Schreiber Instruments or Digimation. I don`t know the price in the states but they can tell you the price and availability. Michael

Your admiration for radiosity effects is understandable, but it needs to be understood that while the radiosity renderings can be drop dead beautiful they do take an apreciable amount of time. In addition to what everyone has said about radiosity, you should also realize that it is usually expressed in terms of a "solution" – because energy continues to bounce throughout the scene it is never really "done" <g>. Lightscape refers to its renderings as "10 minute soultion", "2 hour solution" and even "3-day solution". Getting something on the screen IS quick, but the refinement of the image towards photorealism takes time. Now Lightwave can calculate specular reflections (somwhat unique for a radiosity renderer, & stills only I beleive) but doing so causes another radiosity pass – the reflections are bouncing their own energy, which in turn reflect in the image differently, which in turn bounces more energy….. The real knock out images take TIME, and that's on SGIs. The comment made about tesselation was also a bit understated. Ask Lightwave to toggle to "wireframe" mode, examine where the long face splinters are, toggle back to rendered mode, and examine the shading at those locations. These are areas that take time to get looking right, and you may not notice the shading differences until you shift your viewing position. But don't get me wrong <g>. Lightscape is a wonderful lighting simulator, and as I mentioned to you before, it's a bonified architectural lighting tool and any lighting designer that can get a system is indeed lucky. A 100w PAR and a 500w halogen produce the correct illumination, and you have the ability to custom make any type of real or imaginary light source. The ability to walk around the solved image is stunning. When hardware and software come together in a timely and affordable manner this rendering technique will be truely exciting and extremmely useful. – Phil