Collision Avoidance

Question 1

Name some detecting and avoiding collision approaches

Answer 1

C. Cone in front of agent
C. Character Avoidance Algorithm
R. Rays

Question 2

When it is best to use the Cone?

Answer 2

When other agents or objects are not moving

Question 3

How to calculate time of Closest distance?

Answer 3

t_closest = - (delta_position * cos(teta)) / delta_velocity

Or

t_closest = - (delta_position * delta_velocity) / delta_velocity^2
(inner product)

Question 4

What can we calculate with the Closest distance time?

Answer 4

1- We can calculate the Future positions of the agents

2- Then we can calculate the velocity the agent should take to avoid the collision

Question 5

How do we calculate the new velocity of the character with the Closest distance approach?

Answer 5

V_avoid = P’_character - P’_target

Question 6

What approach should we use to avoid collision with walls and other obstacles?

Answer 6

Rays

Question 6

How does the Rays Approach work?

Answer 6

1- Detect point of collision
2- Calculate normal do the object
3- Make character travel parallel to the wall (use seek movement to that point)

Question 6

Is this affirmation correct?

“Best Ray configurstion varies from scene do scene?”

Answer 6

Yes

Question 7

How to Combine different dynamic movements?

Answer 7

Blending

Priority

Question 8

Problems of a Single Ray

Answer 8

The character has a certain length and can have a collision on its sides

Question 11

What is Blending?

Answer 11

1- Each movement returns its individual output as usual

2- Those outputs are combine using weights

Question 12

What is Priority Movement?

Answer 12

1- Movements are combined in groups of priority

2- Inside each group movements are combined with Blending

Question 13

The purpose of the cone approach is to:
1- ___ the presence of another ___ or ___
2- Use ___ or ___ movements when that happens

Answer 13

1- Detect / character / obstacle

2- evade / flee

Question 14

Some problems of the Cone Approach are:
1- If another agent is ___ the agent from ___ the cone, the agent ___ ___ ___
2- With a lot of agents it ___ work well
3- If two agents are moving ___ to each other but are both ___ of each others cone , they will start to make ___ movements while it would be better if they ___ ___ ___ ___
4- If two agents are in a trajectory ___ ___ while ___ ___ ___, they will not ___ each other in time to avoid it

Answer 14

1- approaching / outside / cannot detect it
2- doesn’t
3- parallel / inside / strange / continue to go forward
4- of collision / side to side / detect

Question 15

Boids is an example of application of ___ where ___ simples types of ___ movements are combined

___ -> move ___ from Boids that are ___
___/___ -> move in the same ___ and at the same ___ with the flock
___ -> move ___ the ___ of the flock

Answer 15

Blending / 3 / dynamic
Separation -> away / too close
Match Velocity/Align -> direction / velocity
Cohesion -> toward / center of mass

Question 16

The Problems of Blending are:
1- ___ movements can cause ___ equilibriums
2- Works badly on environments with ___ ___ ___

Answer 16

1- Opposing / undesired

2- lots of obstacles

Question 17

The problem of Priority movement is:

1- Solves problems with ___ ___ but still has problems with more ___ ___ ___ (like two enemies protecting a Target)

Answer 17

1- unstable equilibriums / complex stable equilibriums