Re: percieving fast motion (was: Re: gettimeofday() and clock)

[Mads Bondo Dydensborg <madsdyd@challenge.dk>]

On Tue, 3 Sep 2002, Gregor Mückl wrote:

> > Not so.  You can percieve motion up to around 70 to 120Hz - depending
> > on the individual, the room lighting conditions and whether the image
> > is centered on your eye or viewed with peripheral vision.  That's why
> > higher quality graphics card/CRT combo's are run at 72 or 76 Hertz.
> > 
> 
> Impossible. Impulses from the receptors in human eyes usually last for 
> about 1/25th second. So it cannot resolve shorter time periods than 
> that. So a sequence of frames with a rate higher than 30fps gets blurred 
> by the human eye.

What I always love about this discussion is people referring to the human 
eye and its physical limitation and experiments carried out on a bunch of 
"normal" people. It like examining 100 officeworkers and concluding that a 
person can not run faster than 20 secs for 100 meter.

Do another experiment. Put a bunch of _really_ hardcore quake gamers on a
lan, with real fast computer and a really fast network. Limit some of
these computers to 30 fps, let others run freely (which should take them
well over the 120 fps the screen can do). Now let them play (one person
gets on machine, never changes). Let the players record their impressions
(but don't let them examine any settings). Now, I will bet good money that
these guys will tell you _exactly_ what machines suck to play on.

When I was playing Quake seriously (I used to run the Danish Quake League 
btw) I was able to tell the difference between 30, 45, 60, 90 fps, no 
problem, and at some point even could tell the difference between a 14 ms 
and 25 ms network connection.

My dad, on the other hand, can't see that his TV flickers (compared to a 
monitor) and experiences anything that last shorter than 0.3 secs as 
"instantanous".

> > I can absolutely assure you that 60Hz is the MINIMUM frame rate I'd
> > consider for most applications.  76Hz would be preferable.

Totally agreed.
> > 
> 
> High framerates are hacks. Only better rendering algorithms are the 
> final solutions IMO. How these algorithms would work is pretty clear. 

This might be true, but

> But they need a vast amount of computational power. 

So, Steve is still right. 

> And I'm actually in 
> a mood to hack a little demo to show off what I think. Maybe tomorrow 
> evening.

That would be interessting.

Mads

-- 
Mads Bondo Dydensborg.                               madsdyd@challenge.dk
Microsoft's stance in this brouhaha is, of course, hypocritical to the
point of being nauseating. 
    -     Eric S. Raymond on MS's demand that AOL use open protocols for IM