POV-Ray : Newsgroups : povray.binaries.animations : Your legs: IK or FK?? (409kbbu) : Re: Your legs: IK or FK?? (409kbbu) Server Time
5 Nov 2024 03:19:32 EST (-0500)
  Re: Your legs: IK or FK?? (409kbbu)  
From: Lewis
Date: 20 Apr 2000 16:03:00
Message: <38FF7016.363854D@netvision.net.il>
Very impressive. I can see a lot of hard work went into this one - how
did you do it?

"Greg M. Johnson" wrote:
> 
> DOES ANYBODY OUT THERE HAVE IK LEGS?
> I mean, does your hip levitate off the ground by some sort of magic, and
> your legs occasionally pick up your feet to move them along and drop
> them?  Kind of like a flying car that keeps dropping sandbags, lifting
> them, and throwing them ahead as it glides along.
> 
> OR ARE YOU LEGS FK?
> That is, is your hip structurally supported off the ground, while one
> foot basically stays put on the ground due to friction, while muscles
> rotate your thigh and shin bones about their joints, and the position of
> your hip is at the mercy of a complicated function of all these
> variables?  Is the position of your knee backsolved by the postion of
> foot and hip or  is it solved by the rotation of your hip alone?
> 
> My legs, at least, are FK!  ;-)
> 
> This animation is a walk cycle of my blobmon involving a true FK based
> walk cycle. No foot slippage, by definition! Am I right in that this is
> a significant accomplishment?  With this kind of cycle, I could have a 4
> or 15 jointed leg, which could be difficult to solve with IK math.  The
> position in Y is determined by locating the "bottom" of the figure with
> 2500 trace calls from -y, and a trace call from y to the floor, so I
> could have it walk up a gently sloping mountain.
> 
> It would not have been possible without various features of Mega 0.4.  I
> was greatly disappointed, however, that the init_spline funciton does
> not work at all (It only works in cases where you could have just as
> easily used the sine function). I spent days tweaking my cycle before I
> figured this out. The motion may not be as smooth as possible, because
> I'm stuck with a linear spline until I can figure this out. I may be
> forced to write my own cosine-spline macro to get what I need!
> 
> Hopefully, this figure doesn't look like a big booger!  ;-)
> 
>   ------------------------------------------------------------------------
>                           Name: thebodywalker11.mpg
>    thebodywalker11.mpg    Type: MPLAYER2 File (video/mpeg)
>                       Encoding: base64


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