[Bf-funboard] Using a single frame of smoke sim

[braeden at nutral.ca]

Hey there!

I have recently been using Cycles volume rendering in various ways and
I am currently using it to generate organic volume shapes for things
like clouds. The unfortunate thing is that once I cache the sim, I
only need one frame of the sim... but since I am animating the scene
(but not the volume), there appears to be no easy way to do this
(unless I am missing something, and I am sorry if I am).

I have found one very clunky solution by caching the sim externally,
finding the cached file of the frame that I would like to use (remain
static throughout the animation), duplicating it repeatedly and
renaming it in proper sequential numbers so Blender thinks it is
moving through the sim cache, but is really just reading the same
cached frame over and over again.

My obvious problem with this is that it is clunky, tedious, and
inefficient. 

I figured out in this process that the final cached frame of the sim
is rendered by blender once it has run out of externally cached files
(ex. cached frames = 100, then from 100 onward it will just use the
data stored in the 100th cached file). This will make the process a
little less clunky, since now I should be able just to copy that
single frame cache into it's own directory and then rename it as the
first frame and Blender will only read it from there on (no need to
duplicate that file over and over again for the length of frames of
the animation).

My hope is that we could make this process even simpler by just making
a UI element with some small functionality to essentially do exactly
this - but with no headache for the end user. I have uploaded a very
simple mockup (marked in a thin rectangular pink box on the right sim
panel) to illustrate what I
propose: http://oi63.tinypic.com/25k7viq.jpg

The idea is just to be able to click a checkbox once a sim has been
cached that is labelled "Static". This will now allow the user to turn
their sim into a static volume and select which frame they would like
to use, where Blender will now ignore data for all other frames and
use the frame the user selects. The hope would be that blender also
has to do less calculations for each frame when rendering, since each
frame uses redundant data.

I know that Blender is overdue for a large overhaul of it's simulation
tools, but I think this would be a simple update that many users would
benefit from, and I assume (and hope) it would be fairly easy to
implement. During my googling for solutions, I found lots of users
looking to do the same, without as much luck as I have figured out.

I hope I am posting to the right mailing list, if I am not, hopefully
someone can point me in the right direction.

Thanks,

Braeden