Hi, for the past couple days I have been getting strange problems in my 3D viewport and I can't figure out how to fix it. There are lots of jagged lines and it generally looks rough. This has only been the case for a few days, and I haven't made any changes to my OS or drivers. I'm running Houdini 10.0.554 on 64 bit Ubuntu 9.04, if that helps. This is what my viewport looks like:

This is usually a case of your near/far clip planes set too far apart, resulting in poor depth buffer aliasing on the GPU. Check to see if they've been manually set in the display options. Also, Camera objects may set near/far to a large range - try increasing near from 0.001 to 0.1 (the range is far/near, not far-near, so this produces a 100x improvement in depth buffer resolution).

Awesome, thanks! The near/far clipping planes in the display options were the problem.