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"Tim Nikias" <tim### [at] gmx de> wrote in news:3d3c5e2d@news.povray.org
> I dont know about anyone else, but you're writing from the distant
> future, 2009 to be precise... How come?
the power of Pov-RAY ;)
--
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M
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On Wed, 21 Jan 2009 21:22:46 -0800, cc wrote:
> This is true... Yes I have made animations where the road follows the car
> instead of the usual car-follows-the-road situation. :) And yes I have
> been having to do trial and error if I want the car to follow the road.
> Trial and error is what I'm trying to make easier... faster. I like your
> idea of differentiating from a pre-defined path... Really turns the problem
> around. :) I'd still like to figure out how to control the car directly in
> a clean, sybolic way if possible (as oppposed to numeric approximations,
> Riemann (sp?) sums etc.) (I'm ignoring floating point roundoff) When you
> say I "would have to compute the Bessel functions (or whatever)
> numerically," do you mean something like for example taking a sum of some
> formula as n goes from 1 to something aribitrarily large? Anyway it's
> starting to sound doubtful that it can reasonably be done symbolically... or
> maybe I should say, not without inventing some new symbols... something to
> go along with the trig functions etc?...
>
> -Charles
Charles, please fix your clock! :-)
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On Tue, 20 Jan 2009 07:50:08 -0500, cc wrote:
> I'm new to ng posting, so let me know if i screw something up. :)
>
> Long background description of the project. If interested read it :)
> otherwise I have a math question at the bottom.
>
> I've been working on a system for scripting car-motion. It's
> geometry-based. ... Based on the idea that when turning, the car will
> revolve around some point which is located at the intersection of where
> the normals (if extended) of all four wheels interrsect.
If I were actually designing a simulation of car motion for car company
and wanted to earn my keep I would certainly use as complex an approach
as this so I could determine lateral strain on struts and tires.
However just to povray it ...
> ************************************************************************
>
> In the spirit of clean mathematical models, I really want to do each
> motion segment in one step using calculus.
...
> If mathematica can't do it, is that a bad sign? I threw a few things
> into the online mathematica integrator. http://integrals.wolfram.com/
> Unfortunately it wasn't able to do them.
>
> Help? Suggestions? Is there a way to approximate these integrals w/o
> iteration?
... is this not a bit on the side of overkill? Assume the front tires
turn exactly in sync and the rear wheels do not affect the resultant
motion and the problem is down to rather simple analytic geometry.
I don't mean to try to talk you out of an interesting problem but I
doubt anything you are talking about is going to improve the realism of
the motion in the least.
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On Fri, 23 May 2003 03:08:20 -0400, simian wrote:
> On Tue, 20 Jan 2009 07:50:08 -0500, cc wrote:
>
>> I'm new to ng posting, so let me know if i screw something up. :)
>>
>> Long background description of the project. If interested read it :)
>> otherwise I have a math question at the bottom.
>>
>> I've been working on a system for scripting car-motion. It's
>> geometry-based. ... Based on the idea that when turning, the car will
>> revolve around some point which is located at the intersection of where
>> the normals (if extended) of all four wheels interrsect.
>
> If I were actually designing a simulation of car motion for car company
> and wanted to earn my keep I would certainly use as complex an approach
> as this so I could determine lateral strain on struts and tires.
>
> However just to povray it ...
>
>> ************************************************************************
>>
>> In the spirit of clean mathematical models, I really want to do each
>> motion segment in one step using calculus.
>
> ...
>
>> If mathematica can't do it, is that a bad sign? I threw a few things
>> into the online mathematica integrator. http://integrals.wolfram.com/
>> Unfortunately it wasn't able to do them.
>>
>> Help? Suggestions? Is there a way to approximate these integrals w/o
>> iteration?
>
> ... is this not a bit on the side of overkill? Assume the front tires
> turn exactly in sync and the rear wheels do not affect the resultant
> motion and the problem is down to rather simple analytic geometry.
>
> I don't mean to try to talk you out of an interesting problem but I
> doubt anything you are talking about is going to improve the realism of
> the motion in the least.
A little while ago, I checked the date on the first replies to this thread
and IIRC, the actual date was 1998! Looks like CC has created an effective
P.B.A-U weed by setting his clock ahead a decade... -_- No offense simian,
I did the very same thing a little while ago. ;-)
--
light_source#macro G(E)sphere{z+E*y*5e-3.04rotate-z*E*6pigment{rgbt#end{
20*y-10#local n=162;1}#while(n)#local n=n-.3;G(n)x}}G(-n).7}}#end//GregE
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