# Collision question =)

Hello guys, im trying to make a pinball but sometimes the ball goes into the wall and pieces of the pinball. i have configured the ball as rigid body, and he runs on a static plane and hit on other pieces (walls, points, etc) i tryed changing radius of the ball, and collisions types but sometimes the ball goes into the walls :S plz help me thx ^^

Hello
the Bullet engine have some difficulties with fast objects, I guess…
Try to subdivide a bit the “walls”?!
Bye

how do you move the ball?

if you use the loc value of the actuator it cant work, since it teleports the object from position to position.

you have to use linV, it should work well then.

greetings
manarius

The ball moves with force and “natural” collisions. The initial launch of the ball is a force motion(Y), and a constant force(-Y) to simulate the gravity (pinball table inclined). The flipper makes a “natural” collision, it acts with a rotation ipo. The biggest problem is sometimes when the ball collides with the walls and pieces of the table it goes into :S sry for my english XDD

I´ve tried making the wall and the ground a single and uniform object, but the ball goes into the wall O.o how can a rigid body go into a static and solid object? xD

I don’t think this will solve your problem.

The thing is, that you have a certain “logic tic rate” of normally 60Hz. Collisions are beeing checked in this pacing.

If your ball is too fast, this is what happens: in tic 1 no collision of ball and wall is detected because the ball is too far away from the wall. From tic 1 to tic 2 the ball may travel so fast and therefor far, that it reaches a location behind the wall. In this case, there won’t be a collision detected either, the ball just runs through the wall.

To solve this problem you have 2 possibilities: a) increase the game engines logic tic rate (see http://www.tutorialsforblender3d.com/GameModule/GameLogicModule_15.html
b) limit the speed of your ball. This can be done in the game logic tab --> advanced --> clamp velocity. You will have to find a velocity max where collisions still work fine but isn’t too slow to make your game lame

Good luck

PS: I had the same problem with my game “Graviballs” (sig): I chose solution b) because increasing the logic tic rate also increases the games CPU load.

sweet tyvm for answering this post :)) exactly what i was looking for