On 12-02-20 09:38 AM, Le_Forgeron wrote:
> Le 20/02/2012 13:34, Tail Kinker a écrit :
>> http://youtu.be/brZ6E_TcKeo
>
>
> Interesting. Nice.
>
> Nevertheless, I still have that disbelieving effect due to instant
> acceleration/deceleration of mass: Let split that Mecha in 5 parts:
>
> * torso
> * right foot
> * left foot
> * right arm
> * left arm
>
> Movement of a foot, as I perceived it in the animation, is either:
>   * not-moving, on the ground
>   * moving full speed above the ground
>
> There seems to be an enormous acceleration at the transition points,
> which seems unlikely as the feet should weight.

A very good point.  I'll take a look at fixing that with a bit of extra 
math.

> Also, they have no forward/backward tilt, whatever the ground. (on the
> second part of the movie, this become visible as the front of the right
> foot stay above the ground)

That is true, and an issue of which I was aware.  Still working on a fix 
for that.

> The cycle of each foot seems to be the mirror of the other (not sure,
> frame per frame analysis is not easy on youtube). 50% on ground, 50%
> moving. I would expect 52% on ground, 48% moving, with a stable transfer
> of weight during the 2%.

Another good point, and one that I think that will be fixed when I fix 
the first point.

> The movement of each foot should be something like a sin (slow start,
> slow end, fast in the middle) in the horizontal direction. On the
> vertical direction, it might be a fast or slow or constant speed raise,
> but the down part should look like a fall: vertical speed is something
> in constant acceleration, vertical position is somehow -y² based
> (inverted parabola)
>
> The arms are moving in mirror of the foot, so far so good. Yet I would
> wonder about their speed&  movement: arms serve two purpose on walk
> (maybe more):
>   * dynamic equilibrium (keep the centre of mass moving in straight line)
>   * reserve of kinetic energy (keep the centre of mass moving without
> acceleration)

True, but in a BattleMech, balance is maintained with a massive pair of 
counter-rotating gyros.  The arms move because the operator expects them to.

Thanks for the comments.  I'll look into an improvement.

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