Physic

IGE built-in 3D physics engine is an integration of the Bullet Physic, which is a 3D physic engine.

Rigidbody

In physics simulation, rigid bodies enable physics-based behaviour such as movement, gravity, and collision. A Rigidbody is the main component that enables physical behaviour for a game object. With a Rigidbody attached, the object will immediately respond to gravity. If one or more Collider components are also added, the game object is moved by incoming collisions.

Property	Function
CCD	Enable/disable Continous Collision Detection mode
Kinematic	Set Rigidbody to Kinematic or Dynamic mode
Trigger	Enable trigger collision events
ActiveState	Set activation state
CollisionGroup	Collision group value
CollisionMask	Collision mask value
Mass	The mass of the object (in kilograms by default).
Friction	Friction value
Restitution	Restitution value (aka bounciness value)
LinearVelocity	Linear velocity
LinearFactor	Linear factor
LinearSleepThreshold	Linear sleeping threshold
AngularVelocity	Angular velocity
AngularFactor	Angular factor
AngularSleepThreshold	Angular sleeping threshold
PositionOffset	Position offset (adjust the center of the physic object)
Constraints	List of constraints applied in Rigidbody

Note

If the game object contains Rigidbody component, it’s Transform will be controlled by the Rigidbody. Thus, to change the transform just apply force or torque to the Rigidbody by using Python Script.

Note

When Trigger is enabled, use Python Script to receive triggered events. Refer to Rigidbody API for more details.

Collision

To configure collision between game objects, you need to use Colliders. Colliders define the shape of the game object for the purposes of physical collisions.

BoxCollider

The BoxCollider is a basic cuboid-shaped collision primitive, which are useful for items such as crates, chests, or floors using thin boxes. It can also be used to create complex collision shape using CompoundCollider component.

Property	Function
Size	Size of the collider in X, Y, Z direction
Margin	Collision margin

Note

Collision margin is used to optimize physic calculation, should keep it larger than 0.

SphereCollider

The SphereCollider is a basic sphere-shaped collision primitive.

Property	Function
Radius	The radius of the sphere shape
Margin	Collision margin

CapsuleColider

The CapsuleCollider is made of two half-spheres joined together by a cylinder, to create a capsule primitive shape.

Property	Function
Height	The total height of the collider
Radius	The radius of the collider width
Margin	Collision margin

CompoundCollider

Compound colliders approximate the shape of an object while keeping a low processor overhead, by combining primitive colliders of the child objects. When you create a compound collider like this, you should only use one Rigidbody component, placed on the owner object in the hierarchy.

Note

CompoundCollider do not work with child objects which contains other CompoundCollider or MeshCollider.

Note

Should have only one Rigidbody attached to the whole hierarchy which the root object contains both CompoundCollider and Rigidbody. Otherwise, the simulation may not work as designed.

MeshCollider

The MeshCollider create Collider from meshes in FigureComponent. It is more accurate for collision detection than using primitives colliders.

Property	Function
ConvexHull	Create and convex hull from mesh
TriangleMesh	Use the triangle mesh
Margin	Collision margin

Note

Using MeshCollider results in higher processing overhead than primitive colliders, so it is best to use MeshColliders sparingly.

Note

Using TriangleMesh is only allowed if the Rigidbody is Kinematic.

Constraints

A constraint is used to connect a Rigidbody to another Rigidbody or a fixed point in space. Constraints apply forces that move rigid bodies, and limits restrict that movement.

FixedConstraint

FixedConstraint restricts an object’s movement to be dependent upon another object. The best scenarios for using them are when you have objects that you want to easily break apart from each other, or connect two object’s movement without parenting.

Property	Function
Bodies Collision	Enable/disable collision between linked bodies
Other body	Other Rigidbody or Softbody component
Break Impulse	The force that needs to be applied for this constraint to break.

HingeConstraint

The HingeConstraint groups together two Rigidbodies, constraining them to move like they are connected by a hinge. It is perfect for doors, but can also be used to model chains, pendulums, etc…

Property	Function
Bodies Collision	Enable/disable collision between linked bodies
Other body	Other Rigidbody or Softbody component
Break Impulse	The force that needs to be applied for this constraint to break
Anchor	The position of the axis around which the body swings, in local space
Axis1	Rotation around Z
Axis2	Rotation around X
Lower Limit	The lowest angle the rotation can go
Upper Limit	The highest angle the rotation can go

SliderConstraint

A SliderConstraint allows a object controlled by Rigidbody to slide along a line in space, like sliding doors, for example.

Property

Function

Bodies Collision

Enable/disable collision between linked bodies

Other body

Other Rigidbody or Softbody component

Lower Limit

Lower limit of the slider

Upper Limit

Upper limit of the slider

SpringConstraint

The SpringConstraint joins two Rigidbodies together but allows the distance between them to change as though they were connected by a spring.

Property	Function
Bodies Collision	Enable/disable collision between linked bodies
Other body	Other Rigidbody or Softbody component
Enable	Enable/disable spring on X, Y, Z axis
Stiffness	Spring stiffness in X, Y, Z axis
Damping	Amount that the spring is reduced when active
Lower Limit	Lower limit of the distance range over which the spring will not apply any force
Upper Limit	Upper limit of the distance range over which the spring will not apply any force

Dof6SpringConstraint

Dof6SpringConstraint incorporate all the functionality of the other constraint types and provide greater customization.

Property	Function
Bodies Collision	Enable/disable collision between linked bodies
Other body	Other Rigidbody or Softbody component
Lower Limit	Lower limit of the axis
Upper Limit	Upper limit of the axis
Target velocity	Target velocity
Bounce	Bounciness
Enable Spring	Enable/disable spring
Stiffness	Spring stiffness value
Damping	Spring damping value
Enable Motor	Enable/disable motor
Max Motor Force	Max motor force
Enable Servo	Enable/disable Servo
Servo Target	Servo target

The first 3 dof axis are linear axis, which represent translation of rigidbodies, and the latter 3 dof axis represent the angular motion. Each axis can be either locked, free or limited.

For each axis:

Lowerlimit == Upperlimit -> axis is locked.

Lowerlimit > Upperlimit -> axis is free.

Lowerlimit < Upperlimit -> axis is limted in this range.

Check Bullet Physic manual document for more information.

Softbody

The soft body dynamics provides rope, cloth simulation and volumetric soft bodies, on top of the existing rigid body dynamics. The Softbody component works with FigureComponent, it manipulates Figure meshes to simulate deformable objects like cloth, fluid, jelly,…

Property	Function
CCD	Enable/disable Continous Collision Detection mode
Kinematic	[Ignored] Softbody is Dynamic object as alway.
Trigger	Enable trigger collision events
ActiveState	Set activation state
CollisionGroup	Collision group value
CollisionMask	Collision mask value
Mass	The mass of the object (in kilograms by default).
Friction	Friction value
Restitution	Restitution value (aka bounciness value)
LinearVelocity	Linear velocity
LinearFactor	Linear factor
LinearSleepThreshold	Linear sleeping threshold
AngularVelocity	Angular velocity
AngularFactor	Angular factor
AngularSleepThreshold	Angular sleeping threshold
PositionOffset	[Ignored] Use mesh data without offset
SelfCollision	Enable/disable collision between parts of the shape
SoftCollision	Enable/disable soft collision
SpringStiffness	Spring stiffness value
RestLengthScale	Scale resting length of all springs
NumIterations	Positions solver iterations (pIterations)
SleepThreshold	Sleeping threshold
GravityFactor	Gravity factor
VelocityFactor	Velocities correction factor (kVCF)
DampingCoeff	Damping coefficient value (kDP)
PressureCoeff	Pressure coefficient value (kPR)
VolumeConvCoeff	Volume conversation coefficient [kVC]
FrictionCoeff	Dynamic friction coefficient (kDF)
PoseMatchCoeff	Pose matching coefficient (kMT)
RigidHardness	Rigid contacts hardness (kCHR)
KineticHardness	Kinetic contacts hardness (kKHR)
SoftHardness	Soft contacts hardness (kSHR)
AnchorHardness	Anchors hardness (kAHR)
AeroModel	Aerodynamic model (default: V_Point) V_Point: Vertex normals are oriented toward velocity V_TwoSided: Vertex normals are flipped to match velocity V_TwoSidedLiftDrag: Vertex normals are flipped to match velocity and lift and drag forces are applied. V_OneSided: Vertex normals are taken as it is F_TwoSided: Face normals are flipped to match velocity F_TwoSidedLiftDrag: Face normals are flipped to match velocity and lift and drag forces are applied F_OneSided: Face normals are taken as it is
WindVelocity	Wind velocity for interaction with the air
Constraints	List of constraints applied

Softbody also works with all type of Constraints, together with Rigidbodies or other Softbodies.

Check Bullet Physic manual document for more information.

PhysicManager

The PhysicManager is automatically created and attached to the root object, to have the global setting of the Physic system.

Property	Function
Deformable	Enable/disable physic with Softbody simulation
Debug	Show Physic debug
NumIterations	Number of iterations per frame
NumSubsteps	Number of substeps. If NumSubSteps > 0, interpolate motion between fixedTimeStep
TimeStep	Fixed time step value (default: 1/60)
UpdateRatio	Update ratio, useful to do slow motion effect
Gravity	Global gravity value

Please refer to Bullet Physic Manual and Python API Document document for more details of Physic usage using IGE.