>MIME-Version: 1.0 >Content-Transfer-Encoding: 7bit >X-Priority: 3 >X-MSMail-Priority: Normal >X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 >Date: Fri, 27 Apr 2001 15:43:38 +0800 >From: Geoff Morris <[EMAIL PROTECTED]> >Subject: Re: [JAVA3D] Sun help! Joined Shapes With Lighting Problem >Comments: To: Kelvin Chung <[EMAIL PROTECTED]> >To: [EMAIL PROTECTED] > >Thanks Kelvin, for investigating this for us ... > >> I can see when the program startup, there is two small >> black line in the initial orientation. Moving the cylinder >> around will sometime see the artifact (under windows). >> > >It's much worse here, as there are perhaps 50 unwanted dots / dotted lines, >although some orientations are better (Windows 98; i810; OpenGL 1.1 or >DirectX 8, Java3D 1.2.1). > >> Under solaris, it works fine. Probably because >> a combination of numerical precision, opengl and >> graphics card give more precise location where >> the disc render. >> > >It's good news that it works somewhere, as it gives us something to work >with. I think that you're suggesting that it isn't Java3D's issue, in that >it's an OpenGL/DirectX/graphics card problem? I guess this means that the >lighting calculations occur outside of Java3D, and that Java3D just passes >the geometry coordinates and vertex normals on. I'm showing my lack of >understanding ... Java3D is my first contact with 3D graphics development, >and OpenGL and DirectX are currently 'black magic' to me. > Actually it also shown up upon more testing but less obvious. The problem is that the edges in the connection are overlapping using the same z depth value. >> To workaround this numerical problem, you >> can add an small offset to create a disc >> with longer length. Then add polygon offset between >> alternative disc to avoid z buffer fighting for >> the small overlap portion. >> > >I had tried this but it's no help. Actually, we've discovered that by >removing the ends of the joining shapes then that works (unattractive but >it's a possible option). > If you are using DirectX version, only negative z offset is support, positive z offset are ignored. - Kelvin ------------ Java 3D Team Sun Microsystems Inc. =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff JAVA3D-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
