So, say I have a halberd with the brilliant energy special ability. Could I use that halberd to strike a creature I can somehow see in the otherside of a sturdy though transparent object? (Think plexiglass)
Could an amulet of mighty fists with brilliant energy prevent me from grappling an undead creature? Actually, does it cause me to partially clip into nonliving surfaces as well?
So, say I have a halberd with the brilliant energy special ability. Could I use that halberd to strike a creature I can somehow see in the otherside of a sturdy though transparent object? (Think plexiglass)
Yes, but only if they're right up on the wall. Remember that only the blade itself is made of brilliant energy (what most people interpret to mean the "significant portion"), so the haft of the halberd would be stopped by the wall. You would have more luck with some sort of long bladed weapon, like a longsword or greatsword.
Could an amulet of mighty fists with brilliant energy prevent me from grappling an undead creature? Actually, does it cause me to partially clip into nonliving surfaces as well?
It depends on how your GM interprets brilliant energy to work on an amulet of mighty fists. Technically speaking, it could make 100% of a monk's body into brilliant energy, therefore dropping them to the center of the earth and causing certain death. Or you could rule that it only works briefly right when you're about to strike somebody.
Personally I would rule that it does prevent you from grappling undead, and that it does allow you to partially clip into nonliving surfaces.