How do you make friction?

[Freddy]

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

[d-soldier]

Friction? Do you mean inertia ?

[Fuzzy]

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

[Freddy]

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 .

[Fuzzy]

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.

[Freddy]

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

[pixelpoop]

this would take 60% off of directional velocity.

directionalvelocity*=.4;

[d-soldier]

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...

[pixelpoop]

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.

[Freddy]

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?

[DocRabbit]

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
}