I was trying to recreate a model that was on my old computer, so I opened XSI, and made a cylinder. I went to Raycast and when I selected my polygons, this happened:

(I know, that's a cube, not a cylinder but I had already closed the one with the cylinder, and FragMe! asked for a pic)
It really hurts my eyes and makes it really hard to makes sure I have every polygon I wanted to select selected. Does anyone know what the problem is?

I can't tell you that I know what the problem is, but I have had the same thing happen before. When I run XSI on my laptop with 3DAnalyze, I have the same problem. This would indicate that though the TnL is rendered through the emulator, there is still a graphics problem. I'd say your graphics card has TnL support, but still isn't powerful enough to render objects correctly in XSI.

And how would I check that?

I gave a possible cause for the problem; I really don't know the solution. If one's found it would help me, too.

Try switching your Anti Aliasing settings for your graphics card to Application Controlled if they aren't already and see if it helps, if not then I have no idea and you should post a topic on the Softimage forums so the people who designed the software can figure it out.

I check my graphics card settings, and it didn't have an anti-aliasing setting, though it did have a anisotropic filtering that I made sure was set to application controlled. The problem isn't that big of an issue for me, though, as I have another computer that handles XSI fine.

Well, I tried again and it's back to normal, so I think it's just one of those things that happens occasionally, and can only be fixed by restarting the computer. Or, in my case, it was.