POV-Ray : Newsgroups : povray.binaries.animations : My semi-IK Macro working a knee Server Time
20 Jul 2024 07:16:36 EDT (-0400)
  My semi-IK Macro working a knee (Message 1 to 6 of 6)  
From: Peter Cracknell
Subject: My semi-IK Macro working a knee
Date: 15 Jul 2001 13:05:05
Message: <3b51cd41@news.povray.org>
Well I don't know if you can call it IK, as it only takes 2 points and finds
a third, but after about 2 hours I managed to produce a macro that takes the
two lengths (upper leg and lower leg in my case) and the co-ordinates off
the waist and foot and produces the knee point.

With that in place I went about animating the foot as if it were running so
that the knee would follow.  All I did was move the foot in a circle
(xpos=sin(clockstuff) ,ypos=cos(clockstuff)) and it produced the following.

There are probably some amazing IK style-running macros/files out there, but
my aim is to produce my own (then I know how to work it!) - has anyone got
any tips on improving this system (does the ankle go in an exact circle or
more of an ellipse?) as I'd like to produce a running man in the end, thanks

Peter Cracknell


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Attachments:
Download 'iktest4.mpg' (479 KB)

From: Peter Cracknell
Subject: Re: My semi-IK Macro working a knee
Date: 15 Jul 2001 15:56:26
Message: <3b51f56a@news.povray.org>
Updated (it's amazing - you spend 99% of the time producing 1% useful output
and 1% of your time producing 99% of useful output)

Peter Cracknell


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Attachments:
Download 'iktest7.mpg' (147 KB)

From: John VanSickle
Subject: Re: My semi-IK Macro working a knee
Date: 15 Jul 2001 16:42:00
Message: <3B5201F1.F5157B13@erols.com>
> Updated (it's amazing - you spend 99% of the time producing 1% useful
> output and 1% of your time producing 99% of useful output)

"Why do 5% of the fishermen catch 95% of the fish?"
"Because 5% of the fish are smarter than 95% of teh fishermen."

Seriously, getting a useful macro idiot-proofed takes a lot of work,
but once done increases your output by more than enough to justify the
time spent.

Regards,
John
-- 
ICQ: 46085459


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From: Rick [Kitty5]
Subject: Re: My semi-IK Macro working a knee
Date: 16 Jul 2001 08:54:45
Message: <3b52e415@news.povray.org>
> Updated (it's amazing - you spend 99% of the time producing 1% useful
output
> and 1% of your time producing 99% of useful output)

tell me about it - i am nearing the end of a programming project (PANIC!)
and so far have yet to hit the magic 1%....

anim looks to fluid, perhaps if you could make the 'feet' actually hit the
floor


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Rick

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From: Rune
Subject: Re: My semi-IK Macro working a knee
Date: 16 Jul 2001 10:52:39
Message: <3b52ffb7@news.povray.org>
"Peter Cracknell" wrote:
> There are probably some amazing IK style-running macros/files
> out there, but my aim is to produce my own (then I know how
> to work it!)

That's always a good strategy!

> has anyone got any tips on improving this system

Replace the cylinders with different objects and give them some patterned
pigments.

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:    http://rsj.mobilixnet.dk (updated June 26)
POV-Ray Users:   http://rsj.mobilixnet.dk/povrayusers/
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From: Jérôme Grimbert
Subject: Re: My semi-IK Macro working a knee
Date: 17 Jul 2001 14:40:45
Message: <3B54832D.9DF2A5F9@free.fr>
Peter Cracknell wrote:
> 
> Well I don't know if you can call it IK, as it only takes 2 points and finds
> a third, but after about 2 hours I managed to produce a macro that takes the
> two lengths (upper leg and lower leg in my case) and the co-ordinates off
> the waist and foot and produces the knee point.

Well, I hope you learned a lot from the resolution of the system,
but the exact mechanical simulation of the knee is not that simple...
If I remember correctly, the axis of rotation moves along the upper leg
when the angle changes. (which mean that the length of the upper leg will
be function of the angle) (And if IRRC, the deplacement of the axis is not
along a straight line.)
But may be you do not need such a precise modelisation.

> 
> With that in place I went about animating the foot as if it were running so
> that the knee would follow.  All I did was move the foot in a circle
> (xpos=sin(clockstuff) ,ypos=cos(clockstuff)) and it produced the following.
> 
> There are probably some amazing IK style-running macros/files out there, but
> my aim is to produce my own (then I know how to work it!) - has anyone got
> any tips on improving this system (does the ankle go in an exact circle or
> more of an ellipse?) as I'd like to produce a running man in the end, thanks
> 

I do not know, but you may gain knowledge by looking at some cartoons tutorial.


P.S.: The animation is running smooth.


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