2.5 Explode Modifier Backwards In Time?


I have been waiting a while for 2.5 because it was supposed to support backwards time for the explode modifier.

I can’t seem to find the time IPO anywhere (IPOs are gone).

Can someone look at my file and explain how to make the explosion modifier work backwards in time?



ras_25_explode_particle.blend (302 KB)

Hello Atom.

Unfortunately this is not possible with the current Blender 2.5, I think. For animation paths you can animate the “Evaluation Time” property in the “Datablock” view of a curve. I have searched a lot but found nothing equal for particles.

Perhaps you can render the scene forward and use the resulting image sequence backward. Of course, I see you can use this only if there is no interaction with other objects in this scene, but this can be one way. You can use PNG with alpha for compositing objects behind the explosion etc.

I am looking for a time ipo replacement too.

In 2.5 can you apply it as shape and then do that backwards?

one solution in 2.5
— not right out of blender - but it works for me.

  1. setup your particle system and the explode modifier
  2. save your 2.5 blend-file with a name, that is necessary for the name of the blendcache!
  3. change the setting for the generated frames per cached-file from the default 10 to 1
    in the particel-system-settings
  4. bake the frames to the disk
  5. check in the blendcache_BLENDERFILENAME directory for the created
    *.bphys files. There should be a single file for every frame of the animation
  6. in linux, on the commandline, i mix the files –
    the last number changes to the first and the first one to the last, and so on.
    thats what i do, quick and dirty in the blendcache directory:
    if the last file has number 100 and they are named: 43756265_000100_00.bphys

mkdir old
mv -v  *.bphys  old
cd old
let i=100; for f in *.bphys; do echo $i, $f; f2=`printf "43756265_000%03.3d_00.bphys" $i`; echo $f2; cp -v $f ../$f2; let i=i-1; done

there are other ways to do this name-translation – maybe easier, who knows?

after this, fire up blender again and load the saved blendfile,
if i press ALT-A to run the animation, it now runs backward. So it is possible to do
a normal animation and combine it …

this illustrates my strong feeling that blender is written by rocket scientists, FOR rocket scientists… not for artists =)