Explode mesh, particles fall through plane, recalculate cache

I’m using Windows XP on one PC and Ubuntu 8.04 Linux on another. Using Blender Version 2.46 RC2. I want to deflect particles from an exploding mesh from a plane underneath the mesh.
I have a cube (mesh) that I explode. Works fine.
I then placed a plane beneath the mesh so that the particles (portions of the mesh) will hit and deflect. Deflection is turned on. Unfortunately, some of the particles fall through the plane. For the particles, I’ve varied Acc Z from 0 to 9.82. No difference. . I’ve varied other settings such as damping and random variation. No luck.
Particle system is Newtonian, Midpoint, Extras are set at Size 1, Mass 1.
For the plane, setting is Deflection. The plane is not a soft body. Think of it as a hard surface like pavement or the ground. Permeability is at 0.0 .
Can anyone tell me how to prevent the particles from falling through the plane?

Also, is there a quick way to clear the cache rather than going back to the Object and Particle Buttons icons each time?


from the BSOD: On the Deflector, Set its Permeability as zero since we don´t want any particle to pass trough.

It is set at zero. That’s what is so odd about the results.

When you setup the defector, did you enable the Kill button?

No, I did not set up the Kill button. I wanted the particles to deflect off the plane surface and still be visible.

I was going by Jahka’s tut. Maybe there is something in it that will help you.


I had used that tutorial when I first started. It enabled me to this point, but I seem to have found something out of the ordinary. I’ve enabled the Kill button to see if it changes anything. No difference for those hitting the ground plane.
Using the cursor keys to advance frame by frame, I’ve noticed that some particles (parts of the exploding mesh) deflect, while others do not. Ev.M.Stack is activated too.

Would the inner face thickness and outer face thickness settings affect this?

I have either overlooked something or found a bug in 2.46 RC2. I’m occasionally getting a Blender crash too.

Other things to try?

You must set kill for the plane object to avoid the exploded pieces going through the palne

I set the Kill button for the plane. The particles that contact the plane embed in it and are not deflected.
Any other recommendations?

I have tried a few experiments with different settings and they all seem to stop at the simple one face plane I have set as a deflector. Even without Kill, I get little bits of my mesh bouncing along the plane until the fall off the edge. I cannot get any to go through the plane. If you want to post a link to your Blend file, I am happy to try it on my Windows box to see if the same thing occurs.

DM, Thanks for the offer. I’ve tried some other settings with a different object - another cube as a deflector - near the exploding cube. It seems to work okay. I’ve tried matching the settings between the successful one and not successful one. No luck. As usual, I’ve probably overlooked something. I’m not familiar with how to post the blend file. How may I send the Blend file to you?

You can upload your blend at a file sharing site. I use http://uploader.polorix.net/. It is free to use and was setup by a fellow Blenderhead. You can then post a link to your file here, or PM me with the link. It could be just a bug in the particle system. There is a thread going in the News forum with people discussing similar issues. Basically, getting stuck at a point where the particles don’t work and clearing the cache does not seem to get them back to the beginning.

DM, Thanks. Will PM you early this evening if okay. Same time zone as you. I have to be away from PC for a while till then. Thanks again.

Testing by DichotomyMatt confirmed that if one has two deflectors (in this case, a plane for a floor and a cube for a wall in an example I made), some of the particles tended to penetrate the plane. Not all particles did so. He found with only one deflector, the particles tended not to penetrate the deflector. I confirmed this with my tests. Thanks to DichotomyMatt for the creative testing method. A workaround is to increase the number of particles making their size smaller so that deflector penetration isn’t as noticeable. I increased the particles by a factor of 10. Seemed to be manageable. Thanks to all for help and advice.