# How to make a ball fall faster on a ramp?

So, I'm making a ball game. Where you pick up the ball, drop it on a ramp, and it flies off in to blocks. The only problem right now is it falls at a normal speed, then lightly falls off, not nearly fast enough to get over the wall and hit the blocks.

Is there any way to make the ball go faster down the ramp? Maybe even make it go faster depending on what height you dropped it from (e.g. if you hold it way above the ramp, and drop it, it will drop faster than if you dropped it right above the ramp.)

• Do you need strict control over the ball's path? If not, I'd suggest slapping on a rigidbody and letting PhysX do the work. – kevintodisco Apr 2 '12 at 16:22
• this can be done with base line physics integration V_f=V_i + a*t considering a is gravity in this scenario, so you can either write up your own physics, or see if Unity has its own physics framework for you to use. – gardian06 Apr 2 '12 at 16:43
• Remember that physics engines expect you to run your simulations at scale so since Unity works in Meters. 1. What size is your ball? If it's really big, the ball will roll like a bolder and not like a pebble. 2. What is the mass on the ball? 3. Is it running with default gravity? 4. What type of PhysicsMaterial are you using? Provide these answers and I can give you some better ideas. – Chuck D Apr 2 '12 at 16:48
• @gardian06 Unity does have it's own physics framework... it integrates PhysX, as I had already mentioned... Also, explicit euler is not the ideal form of integration to use for a physics simulation. – kevintodisco Apr 2 '12 at 16:54
• ktodisco I already have a rigidbody on it, the physics of that aren't strong enough. Guardian I'm already using Unity's engine – Timothy Williams Apr 2 '12 at 18:17

One possibilty would be to use AddForce in the direction of the current velocity of the rigidbody. You could measure the height of the dropping point and use this number to calculate the added force.
Pseudocode:

var r:Rigidbody = ball.rigidbody;
var power:float = 3.0;


• @TimothyWilliams did you try increasing the gravity as well? It's in Edit > Project Settings > Physics. Depending on the scale of your world, you might have to increase gravity to make it look more realistic. – bummzack Apr 3 '12 at 6:05