Caustics can be faked.
MV's Cinema 4D
XL7 has caustics, but in cases where the caustic pattern is known, such as this screwdriver, it may be easier and in some cases faster to get the desired result by using lights.
The screen-capture above is a rendering with refraction turned off. To accurately simulate glass or plastic, it is usually best, but much slower, to use refraction. I kind of like the way it looks both ways. The renderings below have refraction on with a refraction index of 1.59. Click here to view a quicktime movie 9.4MB.

Below is the design I made in After Effects to simulate the caustic rays focused by the screwdriver's lucite. Kind of neat by itself, isn't it?

More glass and a couple of animations of this.