Physics based vehicles made from rigidbodies

Questions & Answers
1

I have an empty game object that I consider the root object for a bunch of prefab cubes of type, Regular, Weapon, and Movement.

Block Types:
Regular: provides structure and a place for other nodes to attach.
Weapon: attaches to Regular nodes and can shoot.
Movement: provides thrust in a desired direction.

Block Prefab Contents:
Blocks consist of: Script for controlling that type of block, a 1x1x1 cube primitive, rigid body with gravity enabled and a mass of 1, cube collider.

So with these block types you create a vehicle. Adding them all to ‘root’ empty game object node.

On your movement function you apply force to your engines and that is when it all breaks down.

I want to move all the cubes as one unit. I figured one way is to add fixed joints to each of the nodes and add it’s adjacent node. This worked alright except there was some noticeable jiggle if I messed up thrust and the ship toppled over. It didn’t look ‘glued’ together. How do I make these blocks stick to each other while manipulating the ‘thrust’ from my engines and make the entire ship behave as a single unit.

Edit:
So one possible solution is to remove the rigid bodies from all the individual blocks, add one to the root gameobject that everything is a child of and add force to that. It will work well enough but what are the options for an entire physics based vehicle that is created from modular parts?

2

Why are you using multiple rigidbodies? If you want them to all appear “glued together” then the root object is all that needs a rigidbody. Just make the Empty Gameobject that is the root be the only object with a rigidbody and everything that is a child of it will move with it. It will take into account all of the children collision meshes.

As for having multiple thrust locations, just use rigidbody.AddForceAtPosition and use the different locations you were trying to set as separate “thrust” rigidbodies.

Rigidbody.AddForceAtPosition Script Reference