Collisions

Question 1

What is collision response

Answer 1

Dealing with the model which decides how objects react after a collision
Usually we detect collisions after it is too late - object is inside a surface

Question 2

What is backtracking

Answer 2

A type of collision response
We use backtracking which allows us to calculate the collision point by going back, very useful for ray tracking intersecting with an object

Question 3

What is “fixing”

Answer 3

a type of collision response
actually a hack, projects back to the closest point of the surface
quite inaccurate but much simpler to compute

Question 4

Complexity of collision detection

Answer 4

The complexity for n dynamics is O(n^2)
(n dynamic objects - not static)
n^2 because we have to do collision checking for every object with each other
- a good method is only checking for collision between close particles

Question 5

Collision detection: Bounding volumes

Answer 5

Finding intersection between bounding boxes
Generally this is accurate and reduces complexity by replacing all objects with surrounding cube
There are different bounding volumes that can be used for more accuracy
AABB, Sphere, OBB, K-DOP

Question 6

What is the sphere bounding volume

Answer 6

Placing a sphere around an object
If the spheres do not intersect, then nor do the objects within
Spheres allow faster algorithm for checking intersection
Hierarchical modeling for collisions:
After we have a collision
We can recursively add smaller spheres within the bounding sphere in a particular place - becomes more and more accurate
So we can limit the search area and detail to just where the collision is occurring