Material Question

[Stucuk]

Is it possible to make it so when a sphere hits a static wall that the sphere will loose no speed from the collision using materials or will there always be some speed lost? Currently im being bad and forcing the velocity of the Sphere to always add upto a certain value, which works fine(My world will only have a sphere that moves, everything else is static, at least what it will collide with).

[Julio Jerez]

if you set restitution to 1.0 then it will bounce off with the same velocity more or less numerical error and engine inacuracies.

[Stucuk]

Im surprised that a value of 1.0 makes it gain speed. Id have thought that if anything it would loose speed when it hit walls.

[Julio Jerez]

It does no realy increase the speed, ahe it does is that the ampound of memento before and afert the collision repmain the same.

that is

M1*v1 + M1*v2 = r * (M1*V1' + M2*V2')

in all thre axis

when r is 1.0 then depend of how Mass and velocity are dirtributed soembody may gain speed but other will lose.

now you may see a Gain in momentum, because of the imperfection of the numerical descrte time simulation, teh impercation of teh contact position,
the imperfecatyion of teh contact force resoltions.
Ther are many factor that all play to add errors to the simulation, but in general the simulation do correlate wit the real world beheavior.

what are you doing?

[Stucuk]

Goal is to make a breakout style game(So i can only guess what mass/force/etc should be). Currently using 1 for the Mass of the ball. Ill proberly have to limit the velocity no matter what, just seemed odd that it would increase.

[JernejL]

The error could be related to some floating point imprecision or have some other cause, you gave no examples that would enable us to find out the origin of the error.

[Stucuk]

you gave no examples that would enable us to find out the origin of the error.

Since Julio stated that it could gain or loose speed i didn't see the point in giving an example as its doing exactly what Julio stated.

[JernejL]

My mistake - i did not read the post properly.