Angry Birds Vs. Racing Games: Contrasting Approaches To Motion Physics In Unity Game Dev
Implementing Projectile Motion for Angry Birds Style Games
Implementing physics for angry birds style trajectory projectiles requires configuring rigidbody velocity and drag properties for arcing paths. The rigidbody velocity variable enables setting an initial velocity vector on launch to propel the projectile forwards. Fine-tuning the rigidbody drag then helps decelerate the object over time for a smooth ballistic arc peaking at the vertex. Further unpredictability can be added through torque forces inducing spin and angular trajectories. Custom physics materials play a key role in tuning impact properties like bounciness for optimized structural destruction upon final collision.
Using Rigidbody Velocity and Drag for Arcing Projectile Paths
The core of angry birds ballistic motion relies on correctly configuring the rigidbody component’s velocity and drag attributes. Rigidbody velocity can be set via script at launch time to an initial vector like (10, 15, 0) m/s to give both horizontal and vertical launch speed. Air drag is then increased incrementally on the rigidbody to add deceleration causing the gradual arc peak and descent. Values between 1 and 10 typically work well depending on the desired hang time. The combination gives the iconic floppy projectile motion angry birds is known for.
Adding Torque and Spin for Unpredictable Trajectories
Additional torque forces can be applied on launch to induce angular spin velocities on the rigidbody for more chaotic projectile motions. The Rigidbody.AddTorque method applies a torque rotation impulse causing left/right and forward/backward spins during flight. This can create more uncertainty in the final destination of angry birds before impact. Careful tuning is neeeded on the torque values to prevent excessive mid-air spinning. Randomized values between 10-100 torque are reasonable for subtle spin effects.
Tuning Physics Materials for Optimized Bounce and Destruction
Custom physics materials are essential for configuring how projectiles bounce and react during final impact. Attributes like bounciness, friction, and destructibility can all be authored on physics materials for angry birds elements. For example, increasing bounciness to 0.8 produces vigorous rebounds upon enviornmental collisions. Raising destructibility also allows the projectiles to demolish certain structures realistically. Advanced material combinations establish key gameplay during final impact.
Simulating Realistic Vehicle Dynamics in Racing Games
Realistic racing game physics requires carefully configured wheel colliders for traction, customizable steering slip angles, and scripted transmission gears for acceleration. Unity’s built-in wheel collider component establishes the ground interaction including friction curves for traction. The wheel colliders should be paired with model suspension elements allowing compression and dampening effects over uneven terrain. Custom steering scripts then help modify slip angles per wheel for simulating loss of grip around corners. Finally, gearbox scripts help mimic engine powerbands and torque for realistic acceleration.
Configuring Wheel Colliders for Traction and Friction
The foundation of racing physics starts with properly authored wheel collider configurations. The wheel collider friction curve establishes how traction force responds to surface materials and vertical loading force. Tuning the extremum slip paramaters affects how easily slippage occurs under acceleration. Softer slip angles can mimic low traction dirt or grass, while higher angles represent grippy asphalt. Tire friction also updates based on simulated vertical weight distribution of the chassis. This creates subtle losses of grip when temporarily airborne over large bumps or jumps.
Implementing Custom Steering Behaviors and Slip Angles
While wheel colliders provide basal traction physics, custom steering scripts help simulate more nuanced grip loss and drift behaviors. Per-wheel slip angle calculations can represent oversteer or understeer effects going into and out of turns. Randomizing slip angle values provides the chaotic sliding expected in real high performance drifting. Calculation of the slip then adjusts wheel alignments dynamically via script to update drift direction realistically.
Scripting Engine and Transmission Simulation for Acceleration
Mapping transmission gears and engine powerbands to acceleration gives a heightened sensation of speed in racing games. As gears shift up, simulated torque curves can be referenced to modify mph appropriately higher. Quick drops in torque and speed occur then when rapidly downshifting gear ratios.vehcileControl scripts then help approximate spinning out when accelerating too hard through a specific gear’s power range. This paired gearbox and engine simulation intensifies the arcade experience.
Integrating Advanced Physics Engines like Bullet or Havok
For developers requiring enhanced physics beyond Unity’s built-in capabilities, 3rd party plugin engines like Bullet Physics or Havok Physics can provide more performant, robust and optimized simulation. The core considerations when evaluating a physics engine plugin include performance cost, simulation stability, and accuracy. For the best results when integrating an external physics system, reducing unnecessary collisions, keeping rigidbody counts optimal, and simplifying large stacked structures improves chances for a smooth experience.
Comparing Built-in vs Plugin Physics Performance
Unity’s native physics and Nvidia PhysX systems provide reasonable real-time approximation at a low performance cost. However for worlds with 100+ dynamic or articulated objects, some limitations around handling compound colliders, fast moving stacks, or complex particle effects become apparent in the form of instability and tunneling issues. This is where dedicated engines like Bullet and Havok can help resolve with higher fidelity calculation and multi-threaded jobs, though this comes at an extra 3-10ms cost per-frame.
Reducing Physics Engine Collisions Overhead
A common pitfall when integrating Bullet or Havok is allowing excess collisions detections to overwhelm the simulation and cause performance dips. Optimizing layers, disabling collision pairs when possible, and using simpler mesh colliders all help reduce the per-frame narrowphase cost. Bullet’s world configuration also exposes collision filtering parameters to explicitly ignore types expected to tunnel without interaction, averting heavy resolution attempt overhead.
Optimizing Large Stacked Rigidbody Structures
Intricately stacked structures like dominos or block towers also stress test real-time physics engines. The multitude of collisions, constraints, andfalls quickly exposes weakness in iteration stability algorithms. Both Bullet and Havok provide settings to increase position correction counts, as well as special compund colliders and constraints to reinforce stability among dense intricate rigidbody structures. Mixing kinematic bodies can also assist in reducing solver load.
Example Code Snippets for Key Physics Components
Underlying the different flavors of motion within Unity games is shared code for applying physics forces, detecting collisions, and connecting objects. While angry birds focuses more on windup impulse forces, and vehicles handle persistent acceleration, snippets below highlight building blocks for authoring scripts across various motion scenarios:
Applying Forces and Impulses for Push/Pull Effects
// Sample impulse thrust on Space Ship rigidbody.AddForce(transform.forward * 5000); // Continuous pull towards planet core rigidbody.AddForce(transform.position - planet.position);
Authoring Custom Gravity and Collision Responses
// Override global gravity locally
Physics.gravity = new Vector3(0, -1.5f, 0);
// Detect collision enter triggers
void OnCollisionEnter(Collision col)
{
if (col.gameObject.tag =="PowerUp")
Destroy(col.gameObject);
}
Scripting Custom Joints and Controller Behaviors
// Configurable spring joint between player and wall SpringJoint joint = gameObject.AddComponent(); joint.spring = 50; joint.damper = 5; // Jetpack controller forces if (Input.GetKey(KeyCode.Space)) { rigidbody.AddForce(Vector3.up * jetpackThrust); }
Conclusion and Next Steps
Summary of Contrasting Physics Approaches
In summary, light-hearted arcade games like Angry Birds leverage impulse and torque forces for unpredictable, whimsical object trajectories. The primary focus lies more in theatrics and physical comedy. By contrast, grounded racing simulations depend highly on nuanced traction behaviors and acceleration mapping for accurately representing speed sensation and grip loss around corners. Both benefit greatly from optimizations like custom physics materials and layers.
Recommendations for Implementing Performant Motion
Careful planning when integrating motion physics ensures smoother runtime experiences. Keeping total rigidbody counts reasonable, reserving collisions only for essential interactions, and eliminating visible object tunneling via filters allows both Unity’s native engine and plugins like Bullet to shine. Matching update rates between fixed timestep logic and the rendering framerate also avoids instability from frame mismatch.
Additional Resources for Advancing Physics Skills
Many online courses and documentation resources exist for bolstering physics capabilities in Unity. Unity’s ECS and DOTS packages also continue advancing native performance for intensive simulations via multi-threading. Finally, assets like Oculus Integration introduce state of the art VR controllers, allowing groundbreaking new motion input paradigms.
