From: Christoph Weber (weber_at_scripps.edu)
Date: Wed Oct 03 2007 - 19:05:21 CDT

I'm wondering if anyone else has seen this, and what to do about it?
On our brandnew iMacs VMD seems to be incapable to display transparent
materials. Everything is displayed solid until the transparency slider
is down to 0.07, at which point the object disappears altogether.
At first I thought it might be a bug in the ATI drivers, but PMV
(Python Molecular Viewer) can smoothly and effortlessly display
transparent objects from solid down to nothing.

Ours are the new aluminum clad iMacs with ATI Radeon HD 2400 XT
graphics cards, running OSX 10.4.10 with all the latest software updates.
training201:~ rcadmin$ /Applications/VMD\
1.8.6.app/Contents/MacOS/startup.command; exit
Info) VMD for MACOSXX86, version 1.8.6 (April 6, 2007)
Info) http://www.ks.uiuc.edu/Research/vmd/
Info) Email questions and bug reports to vmd_at_ks.uiuc.edu
Info) Please include this reference in published work using VMD:
Info) Humphrey, W., Dalke, A. and Schulten, K., `VMD - Visual
Info) Molecular Dynamics', J. Molec. Graphics 1996, 14.1, 33-38.
Info) -------------------------------------------------------------
Info) Multithreading available, 2 CPUs detected.
Info) OpenGL renderer: ATI Radeon HD 2400 XT OpenGL Engine
Info) Features: STENCIL MDE CVA MTX NPOT PP PS GLSL(OVF)
Info) Full GLSL rendering mode is available.
Info) Textures: 2-D (4096x4096), 3-D (256x256x256), Multitexture (8)

Oh, and while we're at it, GLSL rendering does not work under MacOSX
either. It just yields a blank OpenGL display and a spinning
beachball. The same iMac booted into WindowsXP works really well with
VMD, with transparency, GLSL and excellent frame rates (30% higher
than under MacOSX). Hmm...

Thanks for any insight,
Christoph

-- 
|  Dr. Christoph Weber              Sen. Applications Specialist
|  Research Computing, TPC21        858-784-9869 (phone)
|  The Scripps Research Institute   858-784-9301 (FAX)
|  La Jolla  CA  92037-1027         weber_at_scripps.edu
|  http://www.scripps.edu/~weber/
Children are likely to live up to what you believe of them.
  -- Lady Bird Johnson