bobing punch clown

Unity Engine
1

I am trying to make one of those bobing clown punching things and would like to avoid using physics for it. but i am having trouble taking a object hitting it and creating a rotation from that hit to make it look like it is moving correctly.

is anyone better at vector math that could throw out a suggestion or does anyone know if a command in unity to convert a vector impact to a rotation direction?

thanks

2

It sounds like what you are trying to do, is simulate physics, but you don’t want to use physics to do it. :stuck_out_tongue:

3

I know you do not wish to use physics but it would be simpler if you did. Create an empty game object to represent the “base” of the clown. Then I would add a hinge joint connected to the rigid body of the clown. That way he always spins on the bottom point of the hinge joint, but doesn’t move. Use AddForce at Position

4

Using physics carrys to much extra with it. gravity, friction, torque etc. by using just a rotation from a collision vector it reduces the cost (if the script is build cheap) and is 100% controlable. the other issue is that i have some parent objects that have collision on them and i am starting to have to many collisions to account for.

for example the parent and child shouldnt collide… easy to fix. but now i want the parent to collide with the environment but not the child… a little harder. now i want projectiles to collide with the child but not the parent… and the list goes on.

In other engines this can be done with physics channels in PhysX but i cant find a way to do that in Unity so instead i can fix all of the issues by not using physics and by doing based on specific impacts and rotating the object.

I have part of the equation… i am using a Quaternion.AngleAxis for it but now need to convert it to world and find a way to make it an offset to my objects rotation and to not replace my objects current orientation.

does anyone have a good method for taking a Quaternion and just “adding” it to my current orientation?

thanks

5

If your current rotation is recorded as a Quat then you can add them together as you would two ints or what have you. Q1 + Q2.

6

everytime i try to add two quaternions it always says that i cant use a “+” with a left side Quaternion and a right side quaternion. The only way i have found to combine two quaternions in any way is with *… which doesnt combine them but it is a math operator.

if (collision.relativeVelocity.magnitude > 2)
{
var contact = collision.contacts[0];

transform.rotation *= (Quaternion.AngleAxis(30, transform.TransformDirection(contact.normal.right)));
}

This is where i am at so far… closer but still not there.
I would rather do it as an offset because a multiply is wrong. I cant find a solution to add etc. though.
I also need to understand why its not always rotating the same way. i think its because when i change where the object gets hit from i recieve either pos or neg numbers and need to make sure its consistent. hence one of the issues with *.