On Fri, 13 Jan 2006, Charlie Moad wrote:
So in general I get really good performance with chimera, but for some reason I get really bad frame rates with more recent releases on windows with my laptop. It has a really nice card, GeForce 6200TC Go. It is even on a pcix16 bus. I am guessing that since it is a newer chipset, chimera is using shaders of some kind? The molecule looks visually smoother/better than when in linux. In any case, it seems something is getting enabled that really bogs it down, and I would like to be able to disable it.
Sony Vaio FS500 Chimera 1.2184
Sounds like, on Windows, chimera detects that your graphics card supports multisampling, ie., more than one sample per pixel, and is using it. Multisampling is used to reduce the staircase effect visible on polygon edges (ribbons, spheres, sticks, surfaces). You can turn it off by giving the --nomultisample option when you start chimera (edit the chimera shortcut's properties and add --nomultisample to the Target field). There are usually several levels of multisampling supported by the graphics card with tradeoffs between visual quality and performance. Chimera doesn't let you choose (yet), but the graphics driver lets you pick a particular one. Change the "Antialiasing settings" from Application-controlled to particular value (Off, 2x, 4x, 8xS, or 16x on my Quadro -- probably a subset on the GeForce). And the fact that you're not getting the same visual quality on Linux is a bug. Chimera is supposed to behave the same across all platforms. Greg Couch UCSF Computer Graphics Lab gregc@cgl.ucsf.edu