3D Physics Engine Reference

The physics engine simulates realistic object physics, with gravity, forces, joints, etc. It's perfect for games that need to have realistic behaving objects and a gameplay centered around it. Read more explanations about it.

Conditions

Collision
Check if two objects collide.

Collision started
Check if two objects just started colliding during this frame.

Collision stopped
Check if two objects just stopped colliding at this frame.

Character is on given platform
Check if a 3D physics character is on a given platform.

3D physics engine

Simulate realistic object physics with gravity, forces, etc.

Behavior actions

Apply angular impulse (rotational impulse)
Apply an angular impulse (also called a "rotational impulse") to the object. It instantly changes the rotation speed, to give an initial speed for instance.

Apply force (at a point)
Apply a force to the object over time. It "accelerates" an object and must be used every frame during a time period.

Apply force (at center)
Apply a force to the object over time. It "accelerates" an object and must be used every frame during a time period.

Apply force toward position
Apply a force to the object over time to move it toward a position. It "accelerates" an object and must be used every frame during a time period.

Apply impulse (at a point)
Apply an impulse to the object. It instantly changes the speed, to give an initial speed for instance.

Apply impulse (at center)
Apply an impulse to the object. It instantly changes the speed, to give an initial speed for instance.

Apply impulse toward position
Apply an impulse to the object to move it toward a position. It instantly changes the speed, to give an initial speed for instance.

Apply torque (rotational force)
Apply a torque (also called "rotational force") to the object. It "accelerates" an object rotation and must be used every frame during a time period.

Enable layer
Enable or disable a layer for an object. Two objects collide if any layer of the first object matches any mask of the second one and vice versa.

Enable mask
Enable or disable a mask for an object. Two objects collide if any layer of the first object matches any mask of the second one and vice versa.

Angular damping
Change the object angular damping. How much angular speed is lost across the time..

Angular velocity X
Change the object angular velocity on X..

Angular velocity Y
Change the object angular velocity on Y..

Angular velocity Z
Change the object angular velocity on Z..

Treat as bullet
Treat the object as a bullet. Better collision handling on high speeds at cost of some performance.

Density
Change the object density. The body's density and volume determine its mass..

Fixed rotation
Enable or disable an object fixed rotation. If enabled the object won't be able to rotate.

Friction
Change the object friction. How much energy is lost from the movement of one object over another. The combined friction from two bodies is calculated as 'sqrt(bodyA.friction * bodyB.friction)'..

Gravity scale
Change the object gravity scale. The gravity applied to an object is the world gravity multiplied by the object gravity scale..

World gravity on X axis
Change the world gravity on X axis While an object is needed, this will apply to all objects using the behavior..

World gravity on Y axis
Change the world gravity on Y axis While an object is needed, this will apply to all objects using the behavior..

World gravity on Z axis
Change the world gravity on Z axis While an object is needed, this will apply to all objects using the behavior..

Linear damping
Change the object linear damping. How much movement speed is lost across the time..

Linear velocity X
Change the object linear velocity on X..

Linear velocity Y
Change the object linear velocity on Y..

Linear velocity Z
Change the object linear velocity on Z..

Restitution
Change the object restitution. Energy conservation on collision. The combined restitution from two bodies is calculated as 'max(bodyA.restitution, bodyB.restitution)'..

Shape scale
Modify an object shape scale. It affects custom shape dimensions, if custom dimensions are not set the body will be scaled automatically to the object size.

Behavior conditions

Angular damping
Compare the object angular damping. How much angular speed is lost across the time..

Angular velocity X
Compare the object angular velocity on X..

Angular velocity Y
Compare the object angular velocity on Y..

Angular velocity Z
Compare the object angular velocity on Z..

Density
Compare the object density. The body's density and volume determine its mass..

Friction
Compare the object friction. How much energy is lost from the movement of one object over another. The combined friction from two bodies is calculated as 'sqrt(bodyA.friction * bodyB.friction)'..

Gravity scale
Compare the object gravity scale. The gravity applied to an object is the world gravity multiplied by the object gravity scale..

World gravity on X axis
Compare the world gravity on X axis While an object is needed, this will apply to all objects using the behavior..

World gravity on Y axis
Compare the world gravity on Y axis While an object is needed, this will apply to all objects using the behavior..

World gravity on Z axis
Compare the world gravity on Z axis While an object is needed, this will apply to all objects using the behavior..

Has fixed rotation
Check if an object has fixed rotation.

Is treated as a bullet
Check if the object is being treated as a bullet.

Is dynamic
Check if an object is dynamic.

Is kinematic
Check if an object is kinematic.

Is static
Check if an object is static.

Layer enabled
Check if an object has a specific layer enabled.

Linear damping
Compare the object linear damping. How much movement speed is lost across the time..

Linear velocity
Compare the object linear velocity length..

Linear velocity X
Compare the object linear velocity on X..

Linear velocity Y
Compare the object linear velocity on Y..

Linear velocity Z
Compare the object linear velocity on Z..

Mask enabled
Check if an object has a specific mask enabled.

Restitution
Compare the object restitution. Energy conservation on collision. The combined restitution from two bodies is calculated as 'max(bodyA.restitution, bodyB.restitution)'..

Behavior expressions

Expression	Description
`Object.Physics3D::AngularDamping()`	Return the object angular damping. How much angular speed is lost across the time..
`Object.Physics3D::AngularVelocityX()`	Return the object angular velocity on X..
`Object.Physics3D::AngularVelocityY()`	Return the object angular velocity on Y..
`Object.Physics3D::AngularVelocityZ()`	Return the object angular velocity on Z..
`Object.Physics3D::Density()`	Return the object density. The body's density and volume determine its mass..
`Object.Physics3D::Friction()`	Return the object friction. How much energy is lost from the movement of one object over another. The combined friction from two bodies is calculated as 'sqrt(bodyA.friction * bodyB.friction)'..
`Object.Physics3D::GravityScale()`	Return the object gravity scale. The gravity applied to an object is the world gravity multiplied by the object gravity scale..
`Object.Physics3D::GravityX()`	Return the world gravity on X axis While an object is needed, this will apply to all objects using the behavior..
`Object.Physics3D::GravityY()`	Return the world gravity on Y axis While an object is needed, this will apply to all objects using the behavior..
`Object.Physics3D::GravityZ()`	Return the world gravity on Z axis While an object is needed, this will apply to all objects using the behavior..
`Object.Physics3D::InertiaAroundX()`	Return the inertia around X axis of the object (in kilograms · meters²) when for its default rotation is (0°; 0°; 0°)
`Object.Physics3D::InertiaAroundY()`	Return the inertia around Y axis of the object (in kilograms · meters²) when for its default rotation is (0°; 0°; 0°)
`Object.Physics3D::InertiaAroundZ()`	Return the inertia around Z axis of the object (in kilograms · meters²) when for its default rotation is (0°; 0°; 0°)
`Object.Physics3D::LinearDamping()`	Return the object linear damping. How much movement speed is lost across the time..
`Object.Physics3D::LinearVelocityLength()`	Return the object linear velocity length..
`Object.Physics3D::LinearVelocityX()`	Return the object linear velocity on X..
`Object.Physics3D::LinearVelocityY()`	Return the object linear velocity on Y..
`Object.Physics3D::LinearVelocityZ()`	Return the object linear velocity on Z..
`Object.Physics3D::Mass()`	Return the mass of the object (in kilograms)
`Object.Physics3D::MassCenterX()`	Mass center X
`Object.Physics3D::MassCenterY()`	Mass center Y
`Object.Physics3D::Restitution()`	Return the object restitution. Energy conservation on collision. The combined restitution from two bodies is calculated as 'max(bodyA.restitution, bodyB.restitution)'..
`Object.Physics3D::WorldScale()`	Return the world scale.

3D physics character

Jump and run on platforms.

Behavior actions

Abort jump
Abort the current jump and stop the object vertically. This action doesn't have any effect when the character is not jumping.

Maximum falling speed
Change the maximum falling speed of an object.

Allow jumping again
When this action is executed, the object is able to jump again, even if it is in the air: this can be useful to allow a double jump for example. This is not a permanent effect: you must call again this action every time you want to allow the object to jump (apart if it's on the floor).

Forbid jumping again in the air
This revokes the effect of "Allow jumping again". The object is made unable to jump while in mid air. This has no effect if the object is not in the air.

Current falling speed
Change the current falling speed of the object. This action doesn't have any effect when the character is not falling or is in the first phase of a jump.

Current forward speed
Change the current forward speed of the object. The object moves backward with negative values and forward with positive ones.

Current sideways speed
Change the current sideways speed of the object. The object moves to the left with negative values and to the right with positive ones.

Forward acceleration
Change the forward acceleration of an object..

Forward angle
Change the angle used by the character to go forward.

Forward deceleration
Change the forward deceleration of an object..

Forward max speed
Change the forward max speed of the object..

Gravity
Change the gravity applied on an object..

Jump speed
Change the jump speed of an object. Its value is always positive..

Jump sustain time
Change the jump sustain time of an object. This is the time during which keeping the jump button held allow the initial jump speed to be maintained..

Should bind object and forward angle
Enable or disable keeping the object angle and forward angle the same.

Sideways acceleration
Change the sideways acceleration of an object..

Sideways deceleration
Change the sideways deceleration of an object..

Sideways max speed
Change the sideways max speed of the object..

Simulate move backward key press
Simulate a press of the move backward key.

Simulate move forward key press
Simulate a press of the move forward key.

Simulate jump key press
Simulate a press of the jump key.

Simulate move left key press
Simulate a press of the move left key.

Simulate move right key press
Simulate a press of the move right key.

Simulate stick control
Simulate a stick control.

Behavior conditions

Can jump
Check if the object can jump.

Current falling speed
Compare Compare the current falling speed of the object. Its value is always positive..

Current forward speed
Compare the current forward speed of the object. The object moves backward with negative values and forward with positive ones.

Current jump speed
Compare Compare the current jump speed of the object. Its value is always positive..

Current sideways speed
Compare the current sideways speed of the object. The object moves to the left with negative values and to the right with positive ones.

Maximum falling speed
Compare the maximum falling speed of an object..

Forward acceleration
Compare the forward acceleration of an object..

Forward deceleration
Compare the forward deceleration of an object..

Forward max speed
Compare the forward max speed of the object..

Gravity
Compare the gravity applied on an object..

Is falling
Check if the object is falling.
Note that the object can be flagged as jumping and falling at the same time: at the end of a jump, the fall speed becomes higher than the jump speed.

Forward angle
Compare the angle used by the character to go forward.

Is jumping
Check if the object is jumping.

Is moving
Check if the object is moving (whether it is on the floor or in the air).

Is on floor
Check if the object is on a platform.

Jump speed
Compare the jump speed of an object. Its value is always positive..

Jump sustain time
Compare the jump sustain time of an object. This is the time during which keeping the jump button held allow the initial jump speed to be maintained..

Should bind object and forward angle
Check if the object angle and forward angle should be kept the same.

Sideways acceleration
Compare the sideways acceleration of an object..

Sideways deceleration
Compare the sideways deceleration of an object..

Sideways max speed
Compare the sideways max speed of the object..

Behavior expressions

Expression	Description
`Object.PhysicsCharacter3D::CurrentFallSpeed()`	Return Compare the current falling speed of the object. Its value is always positive..
`Object.PhysicsCharacter3D::CurrentForwardSpeed()`	Return the current forward speed of the object. The object moves backward with negative values and forward with positive ones.
`Object.PhysicsCharacter3D::CurrentJumpSpeed()`	Return Compare the current jump speed of the object. Its value is always positive..
`Object.PhysicsCharacter3D::CurrentSidewaysSpeed()`	Return the current sideways speed of the object. The object moves to the left with negative values and to the right with positive ones.
`Object.PhysicsCharacter3D::FallingSpeedMax()`	Return the maximum falling speed of an object..
`Object.PhysicsCharacter3D::ForwardAcceleration()`	Return the forward acceleration of an object..
`Object.PhysicsCharacter3D::ForwardAngle()`	Return the angle used by the character to go forward.
`Object.PhysicsCharacter3D::ForwardDeceleration()`	Return the forward deceleration of an object..
`Object.PhysicsCharacter3D::ForwardSpeedMax()`	Return the forward max speed of the object..
`Object.PhysicsCharacter3D::Gravity()`	Return the gravity applied on an object..
`Object.PhysicsCharacter3D::JumpSpeed()`	Return the jump speed of an object. Its value is always positive..
`Object.PhysicsCharacter3D::JumpSustainTime()`	Return the jump sustain time of an object. This is the time during which keeping the jump button held allow the initial jump speed to be maintained..
`Object.PhysicsCharacter3D::SidewaysAcceleration()`	Return the sideways acceleration of an object..
`Object.PhysicsCharacter3D::SidewaysDeceleration()`	Return the sideways deceleration of an object..
`Object.PhysicsCharacter3D::SidewaysSpeedMax()`	Return the sideways max speed of the object..

This page is an auto-generated reference page about the 3D Physics Engine feature of GDevelop, the open-source, cross-platform game engine designed for everyone. Learn more about all GDevelop features here.