Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Hello Bill and Eric, Thank you both for your feedback. Given that I am commited to using Visad right now for our project -since it has nice looking contours and I don't want to have to reinvent it in Java3D I think I will abandon using transparency and go with contours. This in a way provides the transparency that I want without the complications. Thank you both again. Regards, Surekha --- Bill Hibbard <billh@xxxxxxxxxxxxx> wrote: > Hi Surekha, > > This is an old and well known problem with all > 3-D graphics libraires that are fast enough for > interaction. Efficient 3-D graphics libraries, > such as Java3D, use a Z-buffer algorithm for > depth precedence and for this to render correctly > with multiple transparent layers the layers must > be rendered in an ordered sorted from rear to > front. But the sort order changes as the user > rotates the surfaces in 3-D, and dynamically > re-sorting as the user rotates (and dynamically > changing the geometry used by the graphics > library) would be too slow for interaction. > > We have from time to time experimented with an > alternate implementation of transparency, known > as screen door transparency, available in Java3D. > But it seems not to work (it does work in OpenGL > and is used by Vis5D). But screen door images > look a bit weird viewed close up, even if it did > work in Java3D. > > Bill > > On Fri, 28 Oct 2005, Surekha Chandran wrote: > > > I have an irregular 3D surface - a head with some > EEG > > signal plotted on the top of the head. I use > > DelaunayCustom to set up the Irregular3DSet. Now > > instead of making it an RGB ScalarMap I am using > RGBA > > and I want to make the whole image partially > > transparent. There is a seconday contour plot but > that > > is RGB and is fine as you can see in the images > > attached. > > > > Look at the images included. It is funky. When I > > rotate the image in certain directions I find that > > there are some wierd artifacts. It is like the > colors > > are painted on the inside of the head rather than > on > > the outside. Then there are places where I can see > > clear triangles on the inside and holes. It does > not > > make any sense. Why are there holes in the colors? > Why > > are there light gray bands across the face when I > know > > I have set all the values in that area to be the > same > > exact gray color(the darker shade of gray). > > > > Please help. I looked at Test20 but it does not > seem > > to be describing this problem. I could not find > any > > similar problems in the archives. > > > > Thanks > > > > Regards, > > Surekha > > > > > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam > protection around > > http://mail.yahoo.com > > > > __________________________________ Yahoo! Mail - PC Magazine Editors' Choice 2005 http://mail.yahoo.com
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