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How do you make something slow down when it is traveling?

Friction? Do you mean inertia ?

I'll give you a hint. Jumping/Gravity in GE is a friction.

Friction, as in the resistance of a surface to motion, as of an object sliding or rolling over it. For example, sandpaper on sandpaper creates much resistance; friction . Fuzzy, I see what you mean about jumping, but Im making a soccer type game, so I need the ball to slow down after the physical response. But thanks anyway .

have a friction variable for the actor. normally its set small, as the grass causes some friction. upon collision, take a portion of the velocity off the ball and assign it to whatever it hit.

If the ball crosses over(collides) with a non grass area, perhaps cement, or if its currently in the air, then change the value in the actors friction variable.

Ok , and how would I take a portion of the velocity of the ball?

this would take 60% off of directional velocity.

directionalvelocity*=.4;

in·er·tia /ɪnˈɜrʃə, ɪˈnɜr-/ Pronunciation Key - Show Spelled Pronunciation[in-ur-shuh, i-nur-]
–noun
2. Physics.
a. the property of matter by which it retains its state of rest or its velocity along a straight line so long as it is not acted upon by an external force.

sounds like inertia to me...

did you look up friction as well? they are different, although when one body acts upon another you always have to take both into account to have precise predictions.

It does sound like enertia, but I dont want to create the property of matter that keeps it going or keeps it stopped, I want the resistance that slows it down to a stop. Then thats when I need enertia. Get it?

See if this helps.

SuperGlue=directionalvelocity
VirtualPerpetualMachine=0

Your are looking for something in between these two to bleed off the directionalvelocity of the ball until reaching a zero velocity at which the ball comes to rest.

COF of ball on Grass=.05
COF of ball on Concrete=.01 'Ball would roll much easier on concrete and for a further distance.

Code: Select all

'Check velocity of ball so you don't evaluate it if it is at rest.
'Use this in ball collision with grass area.
if(directionalvelocity!=0)
{
directionalvelocity-=.05;
}


'Use this in ball collision with concrete area.
if(directionalvelocity!=0)
{
directionalvelocity-=.01
}


This hasn't been tested, and would probably work better if you set a variable to a value when ball was colliding with different surfaces, and use the above code to evaluate it along with check for 0 velocity. Then you could place the code in the draw actor event where it needs to be actually.

Define a variable ballinfriction
Set value of ballinfriction to 1 for grass, 2 for concrete in the collisionevent of grass and concrete.

DRAWACTOR event of ball:

Code: Select all

if(ballinfriction==1 && directionalvelocity!=0)
{
directionalvelocity-=.05;
}


'Use this in ball collision with concrete area.
else if(ballinfriction==2 && directionalvelocity!=0)
{
directionalvelocity-=.01
}