# No collision in Softbody Sim (file attached)

**URL:** <https://blenderartists.org/t/no-collision-in-softbody-sim-file-attached/561515>\
**Category:** Particles and Physics Simulations\
**Created:** [January 5, 2013, 2:05pm UTC](https://blenderartists.org/t/no-collision-in-softbody-sim-file-attached/561515 "2013-01-05T14:05:45Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![jasonhan](https://blenderartists.org/letter_avatar_proxy/v4/letter/j/59ef9b/32.png) [@jasonhan](https://blenderartists.org/u/jasonhan)\
**Post date:** [January 5, 2013, 2:05pm UTC](https://blenderartists.org/t/no-collision-in-softbody-sim-file-attached/561515/1 "2013-01-05T14:05:45Z")

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I setup simple mock-up softbody sim with 2 spheres and simply let them fall to collide into each other.  
For some reason, it will properly collide with the ground plane but the 2 spheres won’t collide with one another.  
Can someone please take a look at the attached blend file and let me know where I’ve gone wrong?

[http://www.pasteall.org/blend/18659](http://www.pasteall.org/blend/18659)

Thanks in advance.

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**Author:** ![DavePSB](https://blenderartists.org/letter_avatar_proxy/v4/letter/d/51bf81/32.png) [@DavePSB](https://blenderartists.org/u/DavePSB)\
**Post date:** [January 7, 2013, 1:02pm UTC](https://blenderartists.org/t/no-collision-in-softbody-sim-file-attached/561515/2 "2013-01-07T13:02:22Z")

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Hmm. That was a good one. I found that if you load the file, delete the collision physics on both balls, free all bakes, then reinstate the collision physics on each ball and bake all dynamics, it works! I guess maybe there is a cache that is lingering around. I didn’t try using a cache path other than lib. That might help.

The other thing I found was that if you just load the file, scale one of balls very slightly, then bake, it works! Again, this probably invalidated some existing cache or something.

Bakes and freeing them often trip me up, and I still want to understand them better.

Just a thought - when you prepared the blend file for posting, did you simple Save it, or did you do External Data? If the latter, perhaps that is what posted the offending beginning cache??

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**Author:** ![jasonhan](https://blenderartists.org/letter_avatar_proxy/v4/letter/j/59ef9b/32.png) [@jasonhan](https://blenderartists.org/u/jasonhan)\
**Post date:** [January 7, 2013, 1:08pm UTC](https://blenderartists.org/t/no-collision-in-softbody-sim-file-attached/561515/3 "2013-01-07T13:08:11Z")

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Thanks. I made the simple mistake of having the “collision” before the “softbody sim” in the modifier stack.  
If you switch to ensure that collision is at the bottom, it works every time.  
Thanks for taking the time to review.  
regards

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**Author:** ![Illusionist](https://blenderartists.org/user_avatar/blenderartists.org/illusionist/32/13117_2.png) [@Illusionist](https://blenderartists.org/u/Illusionist)\
**Post date:** [January 8, 2013, 8:23pm UTC](https://blenderartists.org/t/no-collision-in-softbody-sim-file-attached/561515/4 "2013-01-08T20:23:14Z")

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Glad that worked out!