[Bf-committers] bpy.ops.anim.keyframe_insert() massively slow

[Joshua Leung]

Hi,

This function is really not intended for baking scripts. In fact, the
"keyframe" system isn't meant for that at all in general. Only the
"samples" system (which also gets stored in F-Curves, but instead of
keyframes) is designed for this stuff. However, this is currently not
exposed via PyAPI in any useful way, so unless you go via C, there
isn't much you can do about this.

Basically, why I strongly urge all baking to go the other way instead,
is that keyframes are relatively quite "heavy", especially with the
handles (which are of limited importance when you've got a sample on
each frame anyway), and also because all the keyframe tools assume
that they are not densely packed together in a bunch. So, even though
you may have situations where there might be a few relatively
"complex" F-Curves with keyframes, they really aren't as complex as
the ones here.

Now, the functionality your refer to is really intended for inserting
the occasional keyframe (i.e. like a user does through the UI). This
means on average once every 5-10 frames or somewhere in between. For
that, it's perfectly acceptable, and probably expected, that the
curves get recalculated nicely, and that it is fine to resize the
keyframes array one item at a time (assuming that changes are
infrequent, and nice playback speed without heaps of unfilled/unused
mem hanging around is preferred).

The samples on the other hand are based on the concept that in one go,
we're going to set aside a chunk of densely-packed samples spaced
evenly, and that we know exactly the range that these go for, and that
we'd like to populate that set of values NOW (that's what baking tools
do).

So, apart from this not being exposed, why isn't this used more?
Firstly, this was hinted at, but never implemented in the old Blender
anim system too, so it's certainly not an entirely new concept, though
it is probably foreign to most users for that reason. And a few tools
now DO use this, namely sound and F-Curve baking.
Secondly, I have not yet put in place much functionality to tweak this
sort of data. Mainly because it is my intention to implement curve
fitting tools to get a usable set of keyframes out of this noisy data,
since editing such densely packed data is really not too feasible.
This will hopefully come eventually, though there are heaps of other
priorities at the moment before that.

Hopefully this answers the question :)

Aligorith

On Mon, May 3, 2010 at 8:03 PM, Daniel Salazar - 3Developer.com
<zanqdo at gmail.com> wrote:
> (Intended for coders, please don't troll)
>
> So can anything be done to speedup bpy.ops.anim.keyframe_insert? I'm
> using this to bake my scripts since I coudn't find any alternative to
> scriptlinks (fail there from 2.5). My scripts run fast (in an instant)
> but inserting the keyframes can make the execution time go up to
> minutes. Is this lacking optimization? what's happening here?
>
> cheers
>
> Daniel Salazar
> www.3developer.com
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