UNITY – 3D Physic – Joints

Using Joints

Fixed Joint – Spring Joints

1. MAIN TOP MENU> GameObject> Capsule1
– Capsule Collider (Inspector> ‘Add Component’> Physics> Capsule Collider)
– Rigid Body (Inspector> ‘Add Component’> Physics> Rigid Body)
– Fixed Joint (Inspector> ‘Add Component’> Physics> Fixed Joint)

Inspector ‘Add Component’>

2. In the viewport under Capsule 1 create
MAIN TOP MENU> GameObject> Capsule2
– Capsule Collider (Inspector> ‘Add Component’> Physics> Capsule Collider)
– Rigid Body (Inspector> ‘Add Component’> Physics> Rigid Body)
– Spring Joint> Connected Body> Capsule1 (Inspector> ‘Add Component’> Physics> Spring Joint)

3. In the viewport under Capsule 2 create
MAIN TOP MENU> GameObject> Capsule3
– Capsule Collider
– Rigid Body
– Spring Joint> Connected Body> Capsule2

The final structure is:

Capsule1 -> Collider + Rigid Body + Fixed Joint
|
Capsule2 -> Collider + Rigid Body + Spring Joint
|
Capsule3 -> Collider + Rigid Body + Spring Joint

Sping Joint Parameters

Anchor: setup the pivot point of the joint (the orange dot in the scene view)

Spring: (molla) 1= soft spring (molla debole), 10= tight spring (molla più rigida), infinity= no spring (molla infinitamente rigida)

Damper: (ammortizzatore)

Min Distance: minimum lenghth of the spring

Max Distance: maximun lenghth of the spring

Break Force: forza da applicare per rompere il vincolo

Break Torque: momento torcente da applicare per rompere il vincolo

Hinge Joints

Hinge Joints are useful to make doors, windows etc..

Create a Box -> apply: Collider + Rigid Body + Hinge Joint

Hinge Joint Parameters

Anchor: setup the pivot point of the joint (the orange dot in the scene view)

Axis: the joint axis, example: to open a door X=0 Y=1 Z=0

Motor: example-> move a automatic gate-> check ‘Use Motor’, Target Velocity:5 Force:4

Limits: example-> limit the door opening-> check ‘Use Limits’, Limits Min:0 Max:90

Break Force: forza da applicare per rompere il vincolo

Break Torque: momento torcente da applicare per rompere il vincolo