[Bf-committers] [Bf-blender-cvs] SVN commit: /data/svn/bf-blender [21050] branches/blender2.5/blender: Pointcache refresh part 1:

Brecht Van Lommel brecht at blender.org
Sun Jun 21 14:19:44 CEST 2009

Hi Janne,

Great to see this is getting some much needed attention.

I'm not sure I understand the exact cache logic now from looking at the
code. Could you write it down somewhere, what the rules are? Here's the
old rules, at least made it possible for me verify easily if some
behavior was correct or not:

One behavior which I find not so useful is that when you're at say frame
10, and make a change, it seems it only goes back one frame and
simulates that? When changing the initial Normal speed for example
there's almost no effect now, while it will actually have a large
effect. Taking one big step from 1 to 10 may be more useful?

Also I do think that if we're going to show approximate results, it
should be indicated in the UI. At least in the Cache panel, and perhaps
also in the 3d view?

About the continue physics option, that could indeed be part of the
cache settings. But I do think this should be a global option, setting
it per system is tedious. Also the options in the ctrl+B menu which are
also global could have buttons in the cache panel perhaps, they are a
bit hidden now.

I would not call "autocaching" that in the UI, an Exact/Approximate
toggle or so seems more clear, because a lot of what is going on is
already "automatic". The place to implement it, that's probably in
wm_event_system.c, wm_event_do_notifiers. Then all dependency graph
calculations are done centralized before drawing. The code there is just
a few lines now, but as it becomes more complicated, it probably
deserves its own file.

One feature for the point cache that I would like to see is the ability
to define the number of steps simulated. The old particle system had a
fixed number of steps (8 or so by default I think), and in many cases
that's sufficient, and faster and less memory hungry. The point cache
system could support a similar option.


On Sun, 2009-06-21 at 12:16 +0200, Janne Karhu wrote: 
> Revision: 21050
>           http://projects.blender.org/plugins/scmsvn/viewcvs.php?view=rev&root=bf-blender&revision=21050
> Author:   jhk
> Date:     2009-06-21 12:16:52 +0200 (Sun, 21 Jun 2009)
> Log Message:
> -----------
> Pointcache refresh part 1:
> * Particles support larger than 1 frame changes, bigger frame changes can result in inaccurate results, but it's super fast and you get a nice feeling of how the particles behave!
> * "Cache to current frame" button calculates the exact result of particles at current frame.
> * Current state of cache can be protected by making it a bake.
> * Cache is now in memory by default, disk cache is an option.
> * Only "viewport %" number of particles are calculated and cached in viewport, baking and rendering calculate all particles.
> * Info on cached frames and memory usage given in ui.
> * Support for exact "autocaching" of changes and large frame changes(disabled for now until exact place in event system is decided)
> * "Continue physics" is probably deprecated after this and should be removed once sb & cloth use the new cache code.
> Todo:
> * Make softbody & cloth use the new cache things.
> Other changes:
> * Some cleanup of particle buttons.

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