UCA Game Physics & Animation 2 — Questions and Answers
Question 1: Which Rigidbody interpolation mode smooths physics movement by using data from the previous fixed frame?
- Extrapolate
- Interpolate (Correct answer)
- None
- Discrete
Correct answer: Interpolate
Interpolate smooths Rigidbody movement by interpolating between the previous and current fixed-update positions.
Question 2: What does the 'Is Trigger' checkbox on a Collider do?
- Makes the collider visible in the Scene view
- Disables physics collision response but still detects overlaps (Correct answer)
- Adds mass to the Rigidbody
- Enables continuous collision detection
Correct answer: Disables physics collision response but still detects overlaps
A trigger collider generates OnTriggerEnter/Stay/Exit events but does not produce physical collision forces.
Question 3: In Unity's Animator, what is a 'Blend Tree' primarily used for?
- Combining multiple audio clips
- Blending between multiple animation clips based on one or more float parameters (Correct answer)
- Creating inverse kinematics rigs
- Baking NavMesh paths
Correct answer: Blending between multiple animation clips based on one or more float parameters
A Blend Tree smoothly transitions between animations by blending them according to parameter values such as speed or direction.
Question 4: Which Unity physics callback is called when two non-trigger colliders first make contact?
- OnCollisionStay
- OnTriggerEnter
- OnCollisionEnter (Correct answer)
- OnCollisionExit
Correct answer: OnCollisionEnter
OnCollisionEnter is invoked on the frame when two non-trigger colliders first begin overlapping.
Question 5: What is the purpose of Physics Layers and a Layer Collision Matrix in Unity?
- To assign visual rendering order
- To control which layers can collide with each other (Correct answer)
- To set Rigidbody mass per layer
- To define animation state priorities
Correct answer: To control which layers can collide with each other
The Layer Collision Matrix in Physics Settings lets you selectively enable or disable collision detection between pairs of layers.
Question 6: What does setting a Rigidbody's 'Collision Detection' to 'Continuous Dynamic' help prevent?
- Jitter in slow-moving objects
- Fast-moving objects tunneling through thin colliders (Correct answer)
- Overlapping static colliders
- Animation blending artifacts
Correct answer: Fast-moving objects tunneling through thin colliders
Continuous Dynamic detection performs sweep tests to catch collisions for fast-moving Rigidbodies that might otherwise pass through thin geometry.
Question 7: In an Animator Controller, what does the 'Exit Time' transition condition enforce?
- The animation loops forever
- The transition occurs after the current state has played for a specified normalized time (Correct answer)
- The Animator resets to the default state
- The transition fires on the first frame
Correct answer: The transition occurs after the current state has played for a specified normalized time
Exit Time is a normalized value (0–1) representing how far through the current clip the Animator must be before the transition is allowed to trigger.
UCA Game Physics & Animation 2
Which Rigidbody interpolation mode smooths physics movement by using data from the previous fixed frame?