I followed Quanon's tutorials many moons ago and I can't remember how he does it, but I'm fairly sure Gmax has a boolean cut operation, although I use 3ds max so don't hold me to that.
Go to Create, in the drop down box that probably says 'Standard Primitives' select 'Compound Objects' and click on Boolean. For operand A select the model and for operand B select the door. Before doing this make sure the door is aligned where you want it to go in the model.
My WIP: The Liberation of Manaan
Originally Posted by Totalbiscuit
Can tell it's been a busy day, 121 Chrome tabs open
on the geek test
keep you healthy, bright-eyed and slim