We will start this tutorial with creating a trigger_multiple, placing a target_removeweapons entity in front of it and connect them with each other (select the trigger first, then the target and press ctrl+k):
As the title says, this small entity removes weapons when the player walks through the trigger. But before the entity effects something you have to type in several things into the entity window ("n"):
You always have to create another key for each weapon (weapon0, weapon1, weapon2...) and then define its value with def_weaponx ("x" stands for 0-10). In the example above the player would lose a grenade launcher and the nailgun. The row of the weapons doesn't matter (it can also be def_weapon5 and then def_weapon3). Only be sure that you type in weapon0, weapon1, weapon2! For the weapon categories open the pak001.pk4, then go to the "def" directory and search for the player.def. Scroll down until you see "Player Entity Definition". Some lines downwards you'll find the weapon slots.