# SC Joints

Detailed Joint Info

Joint's “Rotation Threshold” refers to the difference in rotation between two particles, and “Velocity Threshold” is the velocity difference (includes direction and speed, of course).

The Rotation Threshold is measured in Radians Per Second, and Velocity Threshold is velocity in max units per second. So if a joint has a rotation threshold of 1.0 and it spins more than 57.2958 degrees per second (one radian), then the joint will break.

Also keep in mind that the particle groups' Elasticity setting plays a large role in determining energy preservation during collisions which will affect both velocity and rotation thresholds.

Joint Type Specific Info

Ball joints do NOT attempt to correct back to their initial alignment.

BASICS

SC Joints can be created in two ways:

1) with the SC Joint Helper (found under Create\Helpers\TP Joints)

2) with the TP “SC Joint” operator (found under the SC category)

For better stability and accuracy use 4+ samples per frame when using lots of joints.

Four samples per frame increases stability because joints are impulse-based and TP has to try iterate and keep all the joints fitted together nicely.

If all your joints are breakable then you can often use Per Frame sampling. Breakable joints allow TP a way to relieve stress and not having to force particles together to maintain the joint relationship.

JOINT TYPES

SC Joint operator and helpers use the SAME NUMBERS!

1 spherical – (friction)

2 fixed

3 spring – (friction, damping, spring, spring initial)

4 cylindrical – (friction)

5 hinge – (friction, angle, angle initial)

6 ball – (friction, angle, angle initial)

7 wobble – (damping, wobble)

8 slider – (damping, length, length initial)

MAX SCRIPT uses DIFFERENT numbers!

0 - Fixed

1 - spherical

2 - cylindrical

3 - ball

4 - hinge

5 - spring

6 - wobble

7 - slider