[gameprogrammer] Re: Spring model

["Peter M." <plm@snow.org>]

At 09:14 PM 2004-04-04, grant hallman wrote:

>Wouldn't it be more realistic to make the friction force proportional to
>speed? Or for computational efficiency, just subtract a small percent of
>any velocity, every frame.

Depends on the friction. For solid objects sliding against each other, no 
velocity dependence is a very good approximation. For air resistance, it is 
hard to tell but generally proportional to velocity and equal to v^x, where 
x is a constant between 1 and 2. I don't know about fluid resistance, but 
I'm guessing its something like air. I don't know about the internal 
friction of a spring, which is probably what the original question was 
really about, but I'm guessing no velocity dependence is pretty close. I 
don't think any real systems would subtract a constant percentage of 
velocity per unit of time, but that might be an easy and good enough 
approximation for a game.