Particles + Deflectors

I know the new Jahka system will fix most if not all of my questions. But it’s too buggy still. It cannot be used in production for what I’m doing. Plus the SVN builds themselves are buggy. So - I’m using the old version, with stable 2.45 in WinVista32. See the linked video:

The large square bounding box around the vessel is the deflector - it’s a slightly lower poly mesh version of the vessel itself. It has thickness, I’ve tried every iteration of normal direction, mesh resolution, bspline on/off, vect on/off, increased keys to 30 - I still can’t get my particles to stay inside the vessel. The deflection settings are all at 0 (permeability, random and dampening).

There are no other forces in this scene. The emitter and deflector are on the same layer - if you watch closely, there is some deflection happening. There is no time IPO on the emitter.

Now - what do I have to do to get particles to truly respect deflectors? Is there no way?

I’ve tried replicating the effect using spherical forcefields and/or vortex fields, but the effect isn’t right, and they are really hard to keep within the boundary anyway.

The new system works almost perfectly in the viewport, but doesn’t render right. it’s as if the frame number of the psys isn’t always in sync with the global frame number. Or sometimes the particles don’t render at all. This is an issue I’ve had before with Blender and particles. Makes me want to download trial of Max just for this scene. (and I hate max!)


I’ve just tried to replicate your setup and had similar problems to you. I fixed them by pumping the number of keys up to 100 (didn’t have much of an effect, but it can help if the problems are caused by funky interpolation) and by checking the normals visually.

I had created a cube with thickness to represent your deflector, but calculating normals inside didn’t work right, nor did calculating normals outside. When I turned on Draw Normals I could see Blender wasn’t calculating them in the way I assumed it would. I had to flip some of the normals by hand, then it worked fine.

I hope this helps.

I’ve done lots of normal flipping with them visible. I’m assuming the normals need to be pointing toward the center, where the emitter is. (my deflector is not a cube - that’s just the bounding box of the cylindrical vessel).
I tried my keys up to 100… seems to work so far. I’ve never had them beyond 30 in any other project, and didn’t think it would make much difference beyond that. Thanks!

Well, when I say thanks rawpigeon, I really mean it!! This problem has been plaguing me on the project for over a week. This project is now past due, but at least I can finish it properly. Thanks a bazillion (or so).

No problem, glad you got it working!

well it’s working, but my render times went from 40s/frame, to almost 3:30/frame!!! and the big particle system hasn’t even started yet.

now it’s from 20s to 5 minutes (with/without particle systems). this is unacceptable.