Re: Re: Anomalous behaviour of Penrose Triangle Demonstration
- To: mathgroup at smc.vnet.net
- Subject: [mg81157] Re: [mg81135] Re: Anomalous behaviour of Penrose Triangle Demonstration
- From: Syd Geraghty <sydgeraghty at mac.com>
- Date: Fri, 14 Sep 2007 03:36:29 -0400 (EDT)
- References: <200709110923.FAA26497@smc.vnet.net> <fc8689$lqa$1@smc.vnet.net> <200709131032.GAA15935@smc.vnet.net>
Thanks to Curtis & Gary for their replies. I hope someone at WRI is following this thread because it certainly appears that we have a V6 graphics/driver bug identified here. I hope a few more of the mathgroup run the code to give more diagnostic input for different OSs & hardware combinations. My machine is a:- Model Name: MacBook Pro 17" Model Identifier: MacBookPro2,1 Processor Name: Intel Core 2 Duo Graphics & driver info: Chipset Model: ATY,RadeonX1600 Type: Display Bus: PCIe VRAM (Total): 256 MB Vendor: ATI (0x1002) Device ID: 0x71c5 Revision ID: 0x0000 ROM Revision: 113-xxxxxx-158 EFI Driver Version: 01.00.158 Syd Geraghty On Sep 13, 2007, at 3:32 AM, WetBlanket wrote: > On Sep 12, 2:59 am, Curtis Osterhoudt <c... at lanl.gov> wrote: >> Hi, Syd, >> >> I have no real insight. I confirm that changing the ViewPoint >> prefactor >> causes the same behavior on my machine. I did not try to evaluate >> the code >> which allows "vp" to be changed via a slider; just rotating the >> graphic >> produced by the first chunk of code causes part of it to disappear >> (somewhat >> randomly). >> Of course, I've been having lots of problems with my ATI >> drivers not being >> compatible with Mathematica 6.0's Graphics3D[] objects, so this >> may be a >> symptom of that. >> >> This is on "6.0 for Linux x86 (32-bit) (June 19, 2007)". >> >> On Tuesday 11 September 2007 03:23:52 you wrote: >> >> >> >>> I would appreciate some insight regarding the Penrose Triangle >>> Demonstration which can be found at:- >> >>> http://demonstrations.wolfram.com/PenroseTriangle/ >> >>> The original source I downloaded when run on my machine displayed a >>> blank panel! >>> (The demonstration ran fine on my machine in "watch web preview" >>> mode!) >> >>> $Version Out[1]= "6.0 for Mac OS X x86 (32-bit) (June 19, 2007)" >> >>> The demonstration source was;- >> >>> Manipulate[ >>> cu[x_, y_, z_, d_] := >>> Cuboid[ {x - d/2, y - d/2, z - d/2}, {x + d/2, y + d/2, z + d/ >>> 2} ]; >>> Graphics3D[ >>> {Opacity[o], >>> cu[0, 15, 30, 7.5], cu[15, 45, 0, 7.5], >>> Table[cu[0, 0, 15 n, 7.5], {n, 0, 3}], >>> Table[cu[0, 15 n, 0, 7.5], {n, 3}] >>> } , >>> ViewPoint -> 200 {-1, -1, 1}, >>> Boxed -> False, >>> PlotRange -> 50 {{-1, 0.8}, {-0.6, 1}, {-0.08, 1}}, >>> ImageSize -> {400, 400} >>> ], >>> {{o, 1, "opacity"}, 0, 1}, TrackedSymbols :> Manipulate] >> >>> I changed the "viewpoint factor" in ViewPoint -> 200 {-1, -1, 1} >>> above to 100{-1, -1, 1} on a hunch and the panel >>> displayed correctly. >> >>> After failing to find any documentation for the use of the >>> "viewpoint >>> factor" I tried setting a range for vp and generating a slider in >>> addition to opacity to see the effects. >> >>> Manipulate[ >>> cu[x_, y_, z_, d_] := >>> Cuboid[ {x - d/2, y - d/2, z - d/2}, {x + d/2, y + d/2, z + d/ >>> 2} ]; >>> Graphics3D[ >>> {Opacity[o], >>> cu[0, 15, 30, 7.5], cu[15, 45, 0, 7.5], >>> Table[cu[0, 0, 15 n, 7.5], {n, 0, 3}], >>> Table[cu[0, 15 n, 0, 7.5], {n, 3}] >>> } , >>> ViewPoint -> vp {-1, -1, 1}, >>> Boxed -> False, >>> PlotRange -> 50 {{-1, 0.8}, {-0.6, 1}, {-0.08, 1}}, >>> ImageSize -> {400, 400} >>> ], >>> {{o, 1, "opacity"}, 0, 1}, {{vp, 10, "ViewPoint Factor"}, >>> 10, >>> 200, 10}, >>> TrackedSymbols :> Manipulate] >> >>> The effects of using the vp slider are very odd. Bits of the graphic >>> start disappearing! >> >>> Any clues as to what is happening here would be appreciated. >> >>> Yet another strange "feature" showed up when I tried to "Save As" >>> the >>> modified demonstration code. >> >>> I cannot successfully save the modified demonstration. >> >>> I suspect that is a WRI safeguard for protecting the integrity of >>> the >>> Demonstrations Project (which is fine by me). >> >>> I can of course save the modified code in a new blank notebook. >> >>> Syd Geraghty >> >> -- >> ========================================================== >> Curtis Osterhoudt >> cfo at remove_this.lanl.and_this.gov >> PGP Key ID: 0x4DCA2A10 >> Please avoid sending me Word or PowerPoint attachments >> Seehttp://www.gnu.org/philosophy/no-word-attachments.html >> ========================================================== > > I am running on a Dell XPS Laptop using Windows XT and the code seems > to work -- nothing much happens when I move the viewpoint slider -- > the display moves slightly -- nothing more. > > Gary > >
- References:
- Anomolous behaviour of Penrose Triangle Demonstration
- From: Syd Geraghty <sydgeraghty@mac.com>
- Re: Anomolous behaviour of Penrose Triangle Demonstration
- From: WetBlanket <Wyvern864@gmail.com>
- Anomolous behaviour of Penrose Triangle Demonstration