The somatic component requires an empty hand. The material component requires a hand to handle the material or a focus (same hand can be perform somatic if spell needs both).
Spells without one of those 2 requirements don't care what your hands are doing.
Hollow unbreakable arrows are the most OP common magic item, and my current method of coming up with insane combat shenanigans.
if you make a steel pipe with one end closed and a nozzle on the other, you can enlarge it, fill with any liquid, and then drop concentration, creating a high pressure squirt gun. (or a pipe bomb, depending if it holds)
If their shield has an emblem holy symbol on it, then it can serve as the material component for their Cleric/Paladin spells.
It gets tricky when a spell has somatic component but not material component. Part 2 of the War Caster feat definitely allows such spells to be cast while both hands are occupied with weapons and/or a shield. If nothing else, they could temporarily stow a weapon to free that hand for casting. Up to the DM whether or not to allow them to draw their weapon again that turn.
DJC is correct. To break it down entirely, assuming no special abilities in play (such as War Caster) that modify things:
Components = None or V: You can wield a weapon and a shield while casting.
Components = M, SM, VM, or VSM: You can wield a weapon and a shield while casting if and only if the weapon or shield can be used as a Focus for the spell and said Focus completely replaces the M component(s).
Components = VS or S: You can't wield a weapon and a shield while casting.
I always thought you needed one free hand to cast a spell even without needing to hold honeycomb for example
You do, though features (for example the war caster feat) can modify this.
Spell has M component -> you need a free hand (it will hold the component). Spell has S component -> you need a free hand (it will make the magical gestures). Spell has both M and S component -> you need a free hand (only one free hand is needed, not two).
My players think they can cast spells with a shield in one hand and weapon in the other...
Command is one spell, components say voice...
I always thought you needed one free hand to cast a spell even without needing to hold honeycomb for example
If the only component for a spell is a vocal component, then you can cast it just by speaking the vocal component -- no hands are involved whatsoever.
The somatic component requires an empty hand. The material component requires a hand to handle the material or a focus (same hand can be perform somatic if spell needs both).
Spells without one of those 2 requirements don't care what your hands are doing.
The only way to cast a material component spell with a weapon and shield is with the ruby of the war mage from xgte
Hollow unbreakable arrows are the most OP common magic item, and my current method of coming up with insane combat shenanigans.
if you make a steel pipe with one end closed and a nozzle on the other, you can enlarge it, fill with any liquid, and then drop concentration, creating a high pressure squirt gun. (or a pipe bomb, depending if it holds)
If their shield has an emblem holy symbol on it, then it can serve as the material component for their Cleric/Paladin spells.
It gets tricky when a spell has somatic component but not material component. Part 2 of the War Caster feat definitely allows such spells to be cast while both hands are occupied with weapons and/or a shield. If nothing else, they could temporarily stow a weapon to free that hand for casting. Up to the DM whether or not to allow them to draw their weapon again that turn.
DJC is correct. To break it down entirely, assuming no special abilities in play (such as War Caster) that modify things:
You do, though features (for example the war caster feat) can modify this.
Spell has M component -> you need a free hand (it will hold the component).
Spell has S component -> you need a free hand (it will make the magical gestures).
Spell has both M and S component -> you need a free hand (only one free hand is needed, not two).