[Physics] 1. Rigidbody rigid body

Click to visit the official website Physics System , Rigidbody Overview , Rigidbody (Rigidbody)

1. Rigid body components

Rigidbodies make the behavior of game objects controlled by physics. Rigidbodies can accept forces and torques, allowing objects to move in a realistic manner. Any game object must contain a rigid body that is affected by gravity, behaves based on applied forces (via scripting), or interacts with other objects via the NVIDIA PhysX physics engine.

Attributes	Function
Mass	The mass of the object (kg by default).
Drag	Affects the amount of air resistance the object has when moving it according to the force. 0 means no air resistance, and infinity makes the object stop moving immediately.
Angular Drag	Affects the amount of air resistance the object has when rotating it according to the torque. 0 means no air resistance. Note that directly setting the object's Angular Drag property to infinity will not stop the object from spinning.
Use Gravity	If this property is enabled, the object will be affected by gravity.
Is Kinematic	If this option is enabled, the object will not be driven by the physics engine, it can only be manipulated by __Transform__. This property is useful for mobile platforms, or if you want to animate a Rigidbody with a HingeJoint attached to it.
Interpolate	Only try one of the provided options if you see jerks in rigid body motion.
● None	No interpolation is applied.
● Interpolate	Smoothes the transition based on the previous frame's transition.
● Extrapolate	Smooth the transform based on the estimated transform for the next frame.
Collision Detection	Useful to prevent fast-moving objects from passing through other objects without detecting collisions.
● Discrete	Use discrete collision detection for all other colliders in the scene. Other colliders use discrete collision detection when testing for collisions. For normal collisions (this is the default).
● Continuous	Use discrete collision detection for dynamic colliders (with rigid bodies) and sweep-based continuous collision detection for static colliders (without rigid bodies). Rigidbodies set to __Continuous Dynamic__ will use continuous collision detection when testing for collisions with the rigidbody. Other rigidbodies will use discrete collision detection. Used for __Continuous Dynamic__ to detect objects that need to collide. (This property has a big impact on physics performance, if you don't have collision issues with fast objects, leave it set to Discrete )
● Continuous Dynamic	Use continuous sweep-based collision detection for GameObjects with __Continuous__ and __Continuous Dynamic__ collisions set. Continuous collision detection will also be used for static colliders (without rigidbodies). For all other colliders, discrete collision detection is used. For fast moving objects.
● Continuous Speculative	Use speculative continuous collision detection for rigidbodies and colliders. This is also the only CCD mode where moving objects can be set. This method is generally less expensive than sweep-based continuous collision detection.
Constraints	Restrictions on rigid body motion:
● Freeze Position	Optionally stops movement of the rigidbody along the world X, Y, and Z axes.
● Freeze Rotation	Optionally stops the rigidbody from rotating around the local X, Y, and Z axes.
Info	Display rigid body information.

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2. Rigid body script

Click to visit the official website Rigidbody Class

2.1. Obtain rigid body

Rigidbody rb;

void Start()
{
    
    
    rb = transform.GetComponent<Rigidbody>();
}

2.2. Adding force

• Add force to rigidbody (at center):AddForce(方向大小，力类型)

/**
 * enum ForceMode
 *  Force：使用刚体的质量向刚体添加连续力   F = m · a  
 *  Acceleration：将连续加速度添加到刚体，忽略其质量  v = a · t
 *  Impulse：使用刚体的质量向刚体添加即时力脉冲   I = F · t = m · a · t = m · v
 *  VelocityChange：将即时速度变化添加到刚体，忽略其质量 
 */
rb.AddForce(new Vector3(0, 0, 1), ForceMode.VelocityChange); // 共 4 个重载

// 上面那句力模型为 VelocityChange 时与下面这句对速度直接赋值效果完全一毛一样
rb.velocity = new Vector3(0, 0, 1);

• Apply force at position. This will apply torque and force to the object:AddForceAtPosition(方向大小，施加力的位置，力类型)

// 共 2 个重载
rb.AddForceAtPosition(new Vector3(0, 1, 0), forcePosition.position, ForceMode.Impulse);

• Apply a force to a rigidbody that simulates an explosion:AddExplosionForce(爆炸力，爆炸中心，爆炸半径，...)

// 共3个重载
rb.AddExplosionForce(100, forcePosition.position, 3);

2.3、Move

• Move the rigid body to position:MovePosition(position)

rb.MovePosition(target.position);

• Rotate the rigidbody to rotation:MoveRotation(rotation)

rb.MoveRotation(target.rotation);