Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
Re: survey: accelerated 3D volumetric rendering
Rick Towler (rtowler@u.washington.edu) writes: > What are peoples experiences with accelerated 3d volumetric rendering. I am > sure very high end unix viz workstations have the ability to accelerate > volumetric rendering but what about lower end hardware. Is this the domain > of high end video adapters only? > > In my case we have a Sun Ultra60 with the Creator3d framebuffer and PC's > running consumer versions of nvidia's Geforce line. The Creator3d is > painfully slow rendering anything. The Geforce cards are quite fast with > your standard polygon rendering but volumetric rendering isn't supported in > hardware. > > Does anyone have any experience with this using nvidia's Quadro line or with > 3dLabs cards? What about other platforms? > > fwiw, Sun just released the Expert3d lite which does support accelerated > volumetric rendering and when bundled runs for $2000. I guess that is low > end.... My experience with volume rendering with several different "inexpensive" graphics cards for PCs is that software rending is *always* faster than hardware rendering. (Not to mention prone to far fewer rendering errors.) I pretty much always have software rendering on as the default, and I make *sure* I have it on for any object graphics programs I distribute that have anything unusual going on in them. Cheers, David -- David Fanning, Ph.D. Fanning Software Consulting Phone: 970-221-0438 E-Mail: davidf@dfanning.com Coyote's Guide to IDL Programming: http://www.dfanning.com/ Toll-Free IDL Book Orders: 1-888-461-0155
David, you are always pushing that software rendering..... :) I can't wait for the day the software renderer is retired. Software rendering is useless for real time rendering of 3d object graphics scenes (at least the scenes I work with). It is true that hardware rendering comes with quirks but at least on the PC the latest generation of nvidia products are quite good. It all comes down to the drivers and in the consumer market nvidia is the only company that I know of shipping decent OpenGL drivers. The professional market is another question. Most people probably shy away from volumes but I thought at least a few med imaging people would pipe up. -Rick Towler "David Fanning" <davidf@dfanning.com> wrote in message news:MPG.1505e00a9af63e39989d6e@news.frii.com... > Rick Towler (rtowler@u.washington.edu) writes: > >> What are peoples experiences with accelerated 3d volumetric rendering. I am >> sure very high end unix viz workstations have the ability to accelerate >> volumetric rendering but what about lower end hardware. Is this the domain >> of high end video adapters only? >> >> In my case we have a Sun Ultra60 with the Creator3d framebuffer and PC's >> running consumer versions of nvidia's Geforce line. The Creator3d is >> painfully slow rendering anything. The Geforce cards are quite fast with >> your standard polygon rendering but volumetric rendering isn't supported in >> hardware. >> >> Does anyone have any experience with this using nvidia's Quadro line or with >> 3dLabs cards? What about other platforms? >> >> fwiw, Sun just released the Expert3d lite which does support accelerated >> volumetric rendering and when bundled runs for $2000. I guess that is low >> end.... > > My experience with volume rendering with several different > "inexpensive" graphics cards for PCs is that software > rending is *always* faster than hardware rendering. (Not > to mention prone to far fewer rendering errors.) > > I pretty much always have software rendering on as the > default, and I make *sure* I have it on for any object > graphics programs I distribute that have anything unusual > going on in them. > > Cheers, > > David > -- > David Fanning, Ph.D. > Fanning Software Consulting > Phone: 970-221-0438 E-Mail: davidf@dfanning.com > Coyote's Guide to IDL Programming: http://www.dfanning.com/ > Toll-Free IDL Book Orders: 1-888-461-0155
Rick Towler (rtowler@u.washington.edu) writes: > David, you are always pushing that software rendering..... :) I can't wait > for the day the software renderer is retired. Well, if nothing else, it's useful for comparing with hardware rendering. As you well know, if you have done any object graphics programming at all, you don't get much feedback sometimes. I've spent hours and hours trying to figure out what I was doing wrong programmatically, only to discover there is a bug in my hardware OpenGL implementation. (Number 9 VooDoo 3D, a hot card in its day. But of course the company is now in Chapter 11). I'd buy an NVidia card if I thought I could get it installed without causing my computer to go bonkers for two weeks. :-( > Software rendering is useless for real time rendering of 3d object graphics > scenes (at least the scenes I work with). You and I are obviously rendering different 3D scenes. :-) I don't find it useless at all. But I can imagine scenarios where that could be the case. > Most people probably shy away from volumes but I thought at least a few med > imaging people would pipe up. I think those guys have real jobs. Probably don't have much time to debate on the newsgroups. :-) Cheers, David -- David Fanning, Ph.D. Fanning Software Consulting Phone: 970-221-0438 E-Mail: davidf@dfanning.com Coyote's Guide to IDL Programming: http://www.dfanning.com/ Toll-Free IDL Book Orders: 1-888-461-0155
Rick, Ok, I'll bite. I don't want to get into the latter part of this thread, but I see major speed increases in 3D performance with GeForce and Quadro cards in HW over SW with a couple of notable exceptions. So, you want to volume render in HW well, you can do 3D texturing or 2D texturing. With 2D texturing, you can use axis aligned slices or shear-warp. Actually, many of the 2D texturing methods can be done in IDL right now (a long time ago, I wrote a HW volume rendering object in .pro for a demo). Volume rendering is really a matter of fill rates, so standard PC gaming HW does a very nice job. See any of the work by Ertl from IEEE vis (code is available for download). The combination of 2D texturing and multi-texturing works very well. Rick Towler wrote: > > What are peoples experiences with accelerated 3d volumetric rendering. I am > sure very high end unix viz workstations have the ability to accelerate > volumetric rendering but what about lower end hardware. Is this the domain > of high end video adapters only? > > In my case we have a Sun Ultra60 with the Creator3d framebuffer and PC's > running consumer versions of nvidia's Geforce line. The Creator3d is > painfully slow rendering anything. The Geforce cards are quite fast with > your standard polygon rendering but volumetric rendering isn't supported in > hardware. The (early) Creator3D was a rasterization only engine. All triangle transforms and lighting are actually in SW. Thus, the card can be poor with high polygon counts, but actually works pretty well for volume rendering applications. The GeForce 3 (announced this week) does have 3D textures if that is what you mean by "volumetric rendering". Up to 512^3 in size. However, the effective framebuffer fill rate of that card has not increased over the GeForce 2. Thus, it will not really be much faster for volume rendering until someone writes a renderer using the pixel pipeline to move "chunks" of the blends into the pixel combiner paths (which could be done). In the current class of cards, the HP, 3D labs and ATI cards all have 3D texturing (actually, the nVidia drivers support it, but it is in SW until the GF3) and there are demos on their sites. If you are looking at the low end, the ATI card is less than $300. You can also use the multi-texturing stuff on the GeForce to get a good approximation of 3D textures (again, see the Ertl papers and web site) for around $400. Or, wait for the GF3 for around $600. For many applications, axis aligned planes with 2D texturing will work. The key to volume performance is fill rate, so it is hard to beat a VooDoo 5500 or GeForce 2 Ultra today (if used correctly). Several people around here use the HP fx10 for volume rendering and like it as well. Finally, the 3D Labs GVX420 and Wildcat cards work pretty well for volumes. Bottom line, I would suggest you not get too caught up in equivocating 3D texturing with volume rendering. This will get very murky soon with DX8 and cards like the GeForce 3. You can definitely get good volume rendering in low end PC cards today. 3D textures are available for several PC cards today as well. Now, how this relates to IDL, short of my initial comments, I am not sure... and this is all IHMO. Ref: http://wwwvis.informatik.uni-stuttgart.de/eng/research/pub/p ub2000/wgh00-rezk.pdf Hope it helps. > > Does anyone have any experience with this using nvidia's Quadro line or with > 3dLabs cards? What about other platforms? > > fwiw, Sun just released the Expert3d lite which does support accelerated > volumetric rendering and when bundled runs for $2000. I guess that is low > end.... > > -Rick Towler -- rjf. Randy Frank | ASCI Visualization Lawrence Livermore National Laboratory | rjfrank@llnl.gov B451 Room 2039 L-561 | Voice: (925) 423-9399 Livermore, CA 94550 | Fax: (925) 423-8704
David Fanning <davidf@dfanning.com> wrote in message news:MPG.1505e00a9af63e39989d6e@news.frii.com... > Rick Towler (rtowler@u.washington.edu) writes: > >> What are peoples experiences with accelerated 3d volumetric rendering. I am >> sure very high end unix viz workstations have the ability to accelerate >> volumetric rendering but what about lower end hardware. Is this the domain >> of high end video adapters only? >> >> In my case we have a Sun Ultra60 with the Creator3d framebuffer and PC's >> running consumer versions of nvidia's Geforce line. The Creator3d is >> painfully slow rendering anything. The Geforce cards are quite fast with >> your standard polygon rendering but volumetric rendering isn't supported in >> hardware. >> >> Does anyone have any experience with this using nvidia's Quadro line or with >> 3dLabs cards? What about other platforms? >> >> fwiw, Sun just released the Expert3d lite which does support accelerated >> volumetric rendering and when bundled runs for $2000. I guess that is low >> end.... > > My experience with volume rendering with several different > "inexpensive" graphics cards for PCs is that software > rending is *always* faster than hardware rendering. (Not > to mention prone to far fewer rendering errors.) > It is my understanding that for volume rendering (using IDLgrVolume) you have no choice but software rendering ( its a software based ray tracing scheme) regardless of the hardware/software rendering switch. IDL does not yet include OpenGL support for volume rendering so advanced graphics cards would not help anyway. Multiple CPU's will help since you can set the HINTS property to use multiple CPU's. Until a standard OpenGL volume rendering scheme becomes available on all platforms IDL supports, they may not jump into it. I hope they do. I got into this a while back when I was looking at a new PC workstation for our lab. I was considering buying the high end Wildcat 4110 card which is blistering fast, especially on our CAD/CAM machines. I opted for a dual Pentium Dell workstation with a G400 dual head card to speed up real time viewing/rendering of our volume objects. One interesting thing to note: on our dual Pentium III 733Mhz Dell, the real time rendering of volume objects is not that much faster than my single CPU office PC (only a Pentium II 350). I would have thought it was at least 2x faster running the same app, but not so with my simple subjective test. My crude measurement is based on spinning a 3D object in our medical app (using Trackball) and visually observing how fast the image is rendered. The worst thing is , my Dell has 512Mb RAM (Win NT4), office PC has 64Mb RAM (Win 98) !! Rich
In article <97j5ma$d01$1@canopus.cc.umanitoba.ca>, "Richard Tyc" <richt@sbrc.umanitoba.ca> wrote: > One interesting thing to note: on our dual Pentium III 733Mhz Dell, the real > time rendering of volume objects is not that much faster than my single CPU > office PC (only a Pentium II 350). I would have thought it was at least 2x > faster running the same app, but not so with my simple subjective test. I once did a IDLgrVolume rendering speed test with a dual-processor Windows NT PC, and found almost a 2x speedup when I set the hints property to use multiple processors. I think the volume was something like 128 x 128 x 32. -- Paul Woodford, Ph.D. Essex Corporation For faster email response, replace us dot net with essexcorp dot com