If you want real caustics
when using max lights, you
need to enable caustics in
the caustics rollout (photon
mapped caustics). Don’t do
this right now, these caus-
tics controls need a tutorial
of their own... Just remem-
ber that you can get nice
caustics effects by using GI
and V-Ray lights much easier.
That is why I prefer using
the light box or V-Ray light
over the max lights. You
simply check the GI caustics
option and you don’t have
to care about other caustic