Finding the closest

ok I'm not completely sure how to explain tis buti'm gonna try...

I am making a 3D pong game.
I added powerups
One of the powerups creates a new ball
When there are to many balls the computer paddle can't figure out the right one to follow

I want it to follow the closest one to it.
How do i find the closest one of a bunch of types?(Or the biggest, fastest, slowest, farthest, etc....)

EntityDistance.

I wouldn't just base the AI on distance, though. You'll probably wan't to consider the direction the ball is travelling, and it's velocity.

what do you mean EntityDistance?

It's the blitz3D command to find the distance between 2 entities.

Or..

Function Distance2D(x1#,y1#,x2#,y2#)
Local dx#=x1-x2
Local dy#=y1-y2
Return Sqr(dx*dx + dy*dy)
End Function

I know what the command does, i just don't get how i can use it to accomplish what explained

Use it to find the distance between the bat entity and the ball entity/entities?

Can you post some code for how you would do it, because i seriously have no clue.

targetball = null
Distance = 100000
for ball = firstball to lastball
if entitydistance(ball,bat)<Distance
Distance = entitydistance(ball,bat)
TargetBall = ball
endif
next

You should have a record of all your bats, using a type will do:
(untested! :P)

Type tBall
 Field entity
End Type

Then you'd create your bat & balls:

bat = LoadMesh("myBat.x")
Local ball.tBall
For i = 1 to 3
 ball = New tBall
 ball\entity = CreateShpere()
Next

Now just call the function in your game, passing it the 'bat' entity

Function NearestBall(bat)

  Local ball.tBall
  Local nearestBall.tBall
  Local nearestDist#

  ;Assume first tBall instance is the nearest
  nearestBall = First tBall
  nearestDistance = EntityDistance(bat,nearestBall\entity)

  For ball = Each tBall
    If ball <> nearestBall
      dist = EntityDistance(bat,ball\entity)
      If dist < nearestDist
        nearestBall = ball
        nearestDist = dist
      End If
    End If
  Next

  Return nearestBall\entity
End Function