[Bf-animsys] NLA Mockups

[bassam]

On Sat, 2009-05-16 at 00:19 +1200, Joshua Leung wrote:
> Hi all,
> 
> To get the discussions rolling again, I've (finally) scanned some of
> the mockups of how I imagined the NLA editor would work. 
> 
> Firstly, the original design docs (written around June-September 2007)
> for the NLA system:
> http://aligorith.googlepages.com/animsys2007_nlaplans.7z
> Some of the things mentioned here are no longer relevant, but the
> parts on NLA should still be largely relevant.

> 
> 
> Keeping this in mind (and the plans I outlined in
> http://aligorith.googlepages.com/250_NLA_GSoc09_overview.doc), I've
One comment on your docs about editing an action being referenced by
multiple strips, maybe if the user is editing keyframes in an action,
then all the strips referencing it could get highlighted in some way?
that way the user knows she is affecting multiple strips, and can do
something about it if it is not intended behavior (if the nla is
visible). I agree that blender should not make assumptions about what
the user wants.

on blending modes:

does it make sense that 'blend' is the same as 'replace' but with a
weight? i.e. 50% weight on the top strip leads to blending, but 100%
weight on the top strip leads to replacing? (this is just devil's
advocate)

add currently could work for little tweak actions, for instance, if you
have recorded some hand shake and want to layer it on top of a larger
hand motion (or camera shake)

subtract I can't come up with a use case for.

multiply I'm not sure about either- I know harkeyman said it would be
useful for certain things but I never understood how ; I'll leave it to
others to come up for a use case for the last two.

>  recently made some more 'modern' mockups:
> - http://aligorith.googlepages.com/250_nla_plans_02.jpg  <--- an
> example of NLA with all the different types of interactions that could
> occur. 
I really think an order of evaluation from the bottom up is better:
1- it is more consistent with the sequence editor.
2- it is more consistent with my understanding of the active action
track, though I could be wrong on that one.

If it is reversed (top down) then the sequence editor should probably be
made to match it (or we should abandon trying to share ui between the
two)- and most nle evaluate bottom up. bottom up is generally more
intuitive for people in this view.

Note: I think e.g. constraint and modifier stacks can remain top down,
and do not need modification, since the ui for them looks quite
different, but if you do change them to bottom -> top, that is ok too
(but probably complexifies the ui code)

*I'm not sure what the curved transistions between track 3 and 4 mean.

> - http://aligorith.googlepages.com/250_nla_plans_01.jpg  <--- honing
> in on this more carefully with a more simple example
personally I like the 'action' line at the top of the nla, I would also
wonder if it might be nice to have a 'clear' button as well as a push
down (or simply by deleting the 'strip' next to the action), use case:
animator is editing on the NLA.
animator wants to tweak a strip's action, so double clicks, or uses a
hotkey/etc to 'activate' the strips's action .
the action is now in the active action slot on top.
animator edit's that action, possibly using the dopesheet or just the 3d
view.
animator does not want the action to be active, and does not need to add
a new strip, so just clear it from being active.

note: what happens if the animator just starts keyframing? does it just
add a new action, or if there is an existing active action, adds the
keys into that one? this seems the most error free way to go, otherwise,
I forsee too much trouble trying to 'guess' the right action to slot the
keys into.

corollary note: there should be an easy way to copy keys/curves from one
action to another, presuming we have added them into the wrong one.

> 
> More examples to come as I create them and have time to boot up the
> old computer with the scanner...
> 
> 
> Joshua
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