that is my understanding as well.
an object only has one 4x4 matrix, and a hierarchy really is just an
operator chaining matrices under the hood, with a local transform being
a commodity representing the last of the matrices in the chain, and the
global being basically an override, but nothing more.
******************************
| Raffaele Fragapane |
| Rising Sun Pictures |
| "Remember, TD is for TopDog" |
******************************
kim aldis wrote:
I'm not sure there is an evaluation order. My understanding of local and
global is that they're both just different representations of the same
thing. In fact, if you think about it and look at the values, they couldn't
be applied one after the other. Concatenating these two matrices would give
you the wrong results.
-----Original Message-----
From: owner-xsi(at)Softimage.COM
[mailto:owner-xsi(at)Softimage.COM] On Behalf Of brad
Sent: 01-March-2006 03:19
To: XSI(at)Softimage.COM
Subject: RE: rigging dilemma: driving a parent with
attributes of the child
I believe the evaluation order can be ascertained by looking
at the node stack, same as with modeling and deformation ops.
Start at the bottom of the kinematic stack and work your way
up. Since the Global node is higher than the Local, anything
applied to Global, such as a constraint happens after
whatever effect is applied to the Local transform.
-------Original Message-------
From: brad friedman <xsibrad(at)fie.us>
Subject: RE: rigging dilemma: driving a parent with
attributes of the
child
Sent: 01 Mar '06 03:12
There's the added complexity of the local transform vs the global
transform. Constraints apply to the global, not the local. But a
child's local transform is not affected by the parent's
translation.
An adjustment to a global seems to trigger a change to the
local and
visa-versa. This is a scenario you don't find in maya as there is
but one transform. I'm actually a bit currious as to the
evaluation
order of the local and global transform in different
scenarios like this one.
-brad
_ANDRE DEANGELIS <ANDRE.DEANGELIS(at)UBISOFT.COM>_ wrote: Yes
I relise
that Kim,
But having tried it and seeing hat it works (at least in a simple
test), I am wondering what makes this colution less than desirable.
Andre
-----Original Message-----
From: owner-xsi(at)Softi! mage.COM
[mailto:owner-xsi(at)Softimage.COM] On
Behalf Of kim aldis
Sent: Tuesday, February 28, 2006 2:29 PM
To: XSI(at)Softimage.COM
Subject: RE: rigging dilemma: driving a parent with
attributes of the
child
Because the rotation of the parent is driven by the child,
but the
rotation of the parent affects the position of the child,
which then
affects the direction of the parent, which affects the
rotation of the
child .....
> -----Original Message-----
> From: owner-xsi(at)Softimage.COM
> [mailto:owner-xsi(at)Softimage.COM] On Behalf Of Andre DeAngelis >
Sent: 28-February-2006 19:04 > To: XSI(at)Softimage.COM >
Subject: RE:
rigging dilemma: driving a parent with attributes of the >
child >
There is only one parameter dependency here.
>
> If you parent one null to another and then apply a direction >
constraint to the parent (to point to the child) it workd
just dandy.
>
>! ; In fact, you can continur to rotate the parent in
branch mode,
to
> offset the whole set-up.
>
> Am I missing something here?
>
> -----Original Message-----
> From: owner-xsi(at)Softimage.COM
> [mailto:owner-xsi(at)Softimage.COM] On Behalf Of kim aldis > Sent:
Tuesday, February 28, 2006 1:48 PM > To: XSI(at)Softimage.COM >
Subject: RE: rigging dilemma: driving a parent with
attributes of the
child > > I'd be intrigued to see how, as rob says, the
child is
dependant upon > the parent which is dependant upon the
child, which
is dependant upon > the parent which is dependant upon the child
which ...... And the > whole thing rapidly crawls up it's
own arse.
Whichever software you > use.
> Would have been the same in SI3D too.
>
> > -----Original Message-----
> > From: owner-xsi(at)Softimage.COM
> > [mailto:owner-xsi(at)Softimage.COM] On Beh! alf Of
David Gallagher
Sent: 28-February-2006 18:39 > > To: XSI(at)Softimage.COM > >
Subject: Re: rigging dilemma: driving a parent with >
attributes of
the > > child > > > > > > Maya has its benefits. It
handles this
situation better > unfortunately.
> >
> > > I don't see how you can avoid a cycle.
> > >
> > > As soon as you tranlsate the child in negative Y the
> parent
rotates > > > causing the child to move causing the parent
to rotate
causing the > > > child to move...
> > >
> > > _rob
> >
> >
> >
> > --
> > David Gallagher
> > Animator, Blue Sky Studios
> >
> > ---
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