Step 1: Spawn the axis holder.
first choose a suitable prop. im using a dryer but you could use a crate, dumpster or other prop. youll find this one in the "Useful construction props" section.
Next, easy weld your prop to the ground.
Step 2: Next spawn a beam
spawn a beam or other long rod. use the stacker stool to add another to the end. if you dont have the stacker, easy weld one beam to the other.
Step 3: Axis
now use the axis tool on the end of the beam and then click the middle of your prop. this will form the rotatable axis.
Step 4: The prop holder
now spawn a prop for your projectile to sit in. im using a laundry cart but you could use a bath or other prop. i smart welded it to the beam but you could use easy weld.
Step 5: Thrusters
add thrusters to the bottom of the prop holder. these will need to be quite powerrful.
Step 6: Rope
freeze your axis arm in the position you want to release the projectile. add a rope from here to the floor to stop the arm from going too far.
Step 7: Prop
select a prop to use for your projectile (im using a gas canister) freeze it in place above the cart. use the prop spawner tool and click on the canister. weld it to the ground and unfreeze. IMPORTANT: select the no collide tool and click on the spawner. if you dont do this it will muck up the whole catapult!
Step 8: Finished!
enjoy your basic catapult! any problems, drop me a pm and ill be happy to help.