Using hinge joint for catapult movement

Questions & Answers
1

Hi, I have a catapult in my project that needs to be used to fire cubes. At first I tried using an animation sequence to raise the catapult arm from its horizontal position to its vertical, rotating it 90 degrees in the X axis. This worked fine until I placed a projectile into the holder and what I found when testing the animation after this is that the projectile cube would clip through the catapult arm, even at slow animation speed. The catapult arm has a mesh collider and a rigid body and the cube has a box collider and rigid body.

Next I tried setting up a hinge point to get the catapult to fire with an invisible counterweight collision (no mesh renderer but still has mesh collider).
This has not worked as expected and when the cube is loaded onto the catapult arm, the arm starts to spin all over the place.

Any suggestions? Or any good tutorials on setting up a catapult?

I can include images if needed

2

My idea is kind of a hack (not 100% reliable solution, probably not the best).

You could apply a force to the projectile for a short amount of time (and turn off collisions between the projectile and the catapult). Maybe change the force over time so the projectile follows a circular path.

Your other option is to set the projectile’s transform’s position while it is being “thrown” by the catapult, and set a velocity when the projectile leaves the catapult, letting the physics engine take care of the rest.