Strangest Way to use Bones

Strangest Way to use Bones

Post by Frère_Orphé » Sat, 02 Dec 2000 04:00:00



How to get a circular movement from a piston (more or less) sinusoidal
motion... using hierarchy, bones, dummies...

I think its impossible to get better than 180 because there lacks a
mild force to make a bone come over its own middle ...

any Idea?

--
Lex legis
Organisation pour un monde plus optionnel

En ce moment
Orphe - Johanne
http://www.491.org/projets/mmm/rphee-jo

 
 
 

Strangest Way to use Bones

Post by M. van Viane » Sat, 02 Dec 2000 04:00:00


Well, Frre, you have hit upon the secret of 3D modelling and
animation.....it is a lot of "smoke and mirrors" type magic. We give the
illusion of real-world form and action, but cheat in it's production. I
see now what you are trying to accomplish.....push the piston to move
the wheel (just as in a real engine). In 3D, we are usually satisfied
with turning the wheel to move the piston......it's an illusion of the
piston moving the wheel, because that is what we know and expect to
happen.........and that is what we see! As you have surmised, the wheel
has no inertia to carry it past the top or bottom of the piston stroke.

The only way I see you might make this happen is to use an expression
controller on the wheel......evaluate it's rotational position; if it is
at Top Dead Center or Bottom Dead Center (0 degrees/180 degree in your
example) have the expression rotate it beyond by a few degrees......I
don't know if you can mix expression controllers and bones, though.

Mel


> How to get a circular movement from a piston (more or less) sinusoidal
> motion... using hierarchy, bones, dummies...

> I think its impossible to get better than 180 because there lacks a
> mild force to make a bone come over its own middle ...

> any Idea?

> --
> Lex legis
> Organisation pour un monde plus optionnel

> En ce moment
> Orphe - Johanne
> http://www.491.org/projets/mmm/rphee-jo


 
 
 

Strangest Way to use Bones

Post by Frère_Orphé » Mon, 04 Dec 2000 08:21:06


I like the way you say it :) but I don't know the expression about "smoke
and mirror" .. ? :)


> Well, Frre, you have hit upon the secret of 3D modelling and
> animation.....it is a lot of "smoke and mirrors" type magic. We give the
> illusion of real-world form and action, but cheat in it's production. I
> see now what you are trying to accomplish.....push the piston to move
> the wheel (just as in a real engine). In 3D, we are usually satisfied
> with turning the wheel to move the piston......it's an illusion of the
> piston moving the wheel, because that is what we know and expect to
> happen.........and that is what we see! As you have surmised, the wheel
> has no inertia to carry it past the top or bottom of the piston stroke.

> The only way I see you might make this happen is to use an expression
> controller on the wheel......evaluate it's rotational position; if it is
> at Top Dead Center or Bottom Dead Center (0 degrees/180 degree in your
> example) have the expression rotate it beyond by a few degrees......I
> don't know if you can mix expression controllers and bones, though.

> Mel


> > How to get a circular movement from a piston (more or less) sinusoidal
> > motion... using hierarchy, bones, dummies...

> > I think its impossible to get better than 180 because there lacks a
> > mild force to make a bone come over its own middle ...

> > any Idea?

> > --
> > Lex legis
> > Organisation pour un monde plus optionnel

> > En ce moment
> > Orphe - Johanne
> > http://www.491.org/projets/mmm/rphee-jo

--
Lex legis
Organisation pour un monde plus optionnel

En ce moment
Orphe - Johanne
http://www.491.org/projets/mmm/rphee-jo

 
 
 

Strangest Way to use Bones

Post by M. van Viane » Mon, 04 Dec 2000 10:12:06


Sorry,.....your English is excellent and I thought you would
understand... The phrase means to deceive or fool one into thinking that
what they percieve is actually happening, usually by means of hiding
what is really happening (smoke) or making it look like it is happening
(mirrors)....here's another definition from Google...

"The phrase, popularized by newspaper columnist Jimmy Breslin c.1975,
has been said to derive from carnie slang for magic acts and `freak
show' displays that depend on `trompe l'oeil' effects...."

Rgds,

Mel


> I like the way you say it :) but I don't know the expression about "smoke
> and mirror" .. ? :)

> [snip]

 
 
 

Strangest Way to use Bones

Post by Frère_Orphé » Wed, 06 Dec 2000 04:00:00


thanx ;)


> Sorry,.....your English is excellent and I thought you would
> understand... The phrase means to deceive or fool one into thinking that
> what they percieve is actually happening, usually by means of hiding
> what is really happening (smoke) or making it look like it is happening
> (mirrors)....here's another definition from Google...

> "The phrase, popularized by newspaper columnist Jimmy Breslin c.1975,
> has been said to derive from carnie slang for magic acts and `freak
> show' displays that depend on `trompe l'oeil' effects...."

> Rgds,

> Mel


> > I like the way you say it :) but I don't know the expression about "smoke
> > and mirror" .. ? :)

> > [snip]

--
Lex legis
Organisation pour un monde plus optionnel

En ce moment
Orphe - Johanne
http://www.491.org/projets/mmm/rphee-jo