[Bf-committers] Fully qualified names for channels in actions?

Nathan Vegdahl cessen at cessen.com
Tue Sep 20 08:35:14 CEST 2011


> can't you just parent all 3 objects to
> an empty and animate that?

He is not talking about all 3 objects moving identically, or even
identically with an offset.

Rather, he is talking about the 3 objects having (potentially) fully
independent motion from each other, but all stored in the same action.
 In other words, he's asking for actions to be able to contain more
than one object's animation at a time, in the same way that actions
can contain more than one bone's animation at a time.

For this to be possible the animation channels in actions would have
to be "fully qualified".  e.g. instead of just "x location" you would
have "x location of cube" and "x location of sphere".  That way you
could have separate animation for the cube's and sphere's x location,
but still stored in the same action without conflicting or
over-writing each other.

I should amend my previous response to Tobias and point out that
action channels can already have "fully qualified" names, because they
just use relative RNA paths to specify what property they reference.
The RNA path is always evaluated relative to what the action is
assigned to.

So in theory you can assign an action to the scene, and have the RNA
paths include the object.  You can use the python api to construct
such a situation if you like, but IIRC the depgraph cannot handle that
right now, so it doesn't work reliably and can often do weird funky
things.  Therefore there are no tools to allow the user to construct
something like that easily, and Blender's animation workflow depends
heavily on armatures for any situation where there are multiple
"objects" (bones) with related animation.  This unfortunately does not
provide good solutions for all cases, but it provides at least
workable (even if sometimes annoying) solutions for perhaps 80%+ of
cases.

Note, however, that the animation system is not the only thing with
this weird addiction to armatures.  The library linking proxy system
is that way as well.  I can't speak for the developers, but I'm hoping
(fingers crossed) that we can slowly migrate away from these
historical limitations.  In the mean time, you can usually work around
it or brute-force some solutions, even if it isn't ideal or
user-friendly.

Tobias: out of curiosity, do you have a specific use-case in mind that
you want this for?

--Nathan


On Mon, Sep 19, 2011 at 10:11 PM, Knapp <magick.crow at gmail.com> wrote:
> On Tue, Sep 20, 2011 at 4:39 AM, Nathan Vegdahl <cessen at cessen.com> wrote:
>>> In this scene you have three objects. Every object
>>> has it's own action and it works well. But for some animations it could
>>> be very useful to store that animation of all three objects in one
>>> action
>
> It is very possible I don't get what you are saying but can't you just
> parent all 3 objects to an empty and animate that?
>
>
> --
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