>Hi there, > >I'm seeing some strange behavior when I switch from software >rendering to hardware rendering when looking at volume >rendered data. In particular, when I look at >VolumeRenderingSimple.net with software rendering I can >correctly see through the slab and make out the 3-dimensional >shape within. However, when I switch to hardware >rendering (in the Rendering Options panel) the interior >shape disappears (the volume becomes opaque) and I only >get a projection of the interior shape onto 2 of the 6 planes >bounding the volume. > >Am I doing something wrong here, or is my hardware >just not up to snuff? > >I'm using an SGI Octane with SI graphics (which I'm >told is the basic board) on IRIX 6.4, >and this is for openDX 4.0.5 from the binary archive. > > >Thanks! > >don. > >
Frankly, I've never had any luck with hardware trying to do multiple opacities. The same thing should happen if you line up several 2D layers, set a range of opacities on them and try to look through them (i.e, it's not volume rendering itself). I stick to software rendering for better pictures, albeit slower to update. My experience so far has been limited to SGI Indigo2 Extreme graphics, though we have Octanes being built next door: hope to get one soon! It's not clear to me if this is a limitation of the hardware or the implementation of GL calls made within DX. But it is a problem that's existed for a long time, commercial and open versions, many different platforms (I also used to have graphics cards in RS6Ks -- blech!). Chris Pelkie Vice President/Scientific Visualization Producer Conceptual Reality Presentations, Inc. 30 West Meadow Drive Ithaca, NY 14850 [EMAIL PROTECTED] (607) 257-8335 or (607) 254-8794
