Can't control rigid bodies...

So I have this little scene with rigid bodies. No matter what, the rigid bodies explode away from each other. I have no idea why.
Blend: http://www.pasteall.org/blend/28654

If you set the collision shape of all your shards to ‘convex hull’, it seems to work

Well, I did that and it works better… except that now some of the shards are randomly flying upwards and bouncing around.

you can also change the damping value. I think there are a couple other settings you can fool with too. I recall a tutorial that explained how to keep stacked objects from shifting when physics was activated. I think it was one of Andrews.

Interesting. I’ve used fracture before and it hasn’t caused this kind of exploding. Though I’ve seen this sort of thing before, can’t remember where…

There are some really powerful addons for Bullet Physics, particularly “Bullet Constraints” – look for it in the forum; there are good video tutorials on how to use it.

The key change I made to your .blend was to the Rigid Body Dynamics for each piece – I checked “Enable Deactivation” AND checked “Start Deactivated.” This causes the physics to wait to engage until something else bumps into it. So when the sphere hits the block, it all explodes more or less how it did before, but at least the sphere seems to “motivate” the explosion. Plus it blocks some of the upward-moving pieces, which helps to increase the realism.

You also need to make your moving sphere a Rigid Body (right now it just passes through the box without doing anything). I removed the keyframes, made it an active Rigid Body, and upped the weight and size significantly. I also turned down the number of Steps per Second in your Rigid Body world settings (1000, in my experience, can actually over-solve the simulation, creating hyper-real results) as well as the iterations. And I tweaked a few other things to taste that I can’t recall.

It isn’t perfect, but it could pass in a pinch. The above add-on can make a HUGE difference, though. Check it out.

http://www.pasteall.org/blend/28677
(PS If the sphere doesn’t work on the first go, under Rigid Body Tools: Remove, then Add Active. Not sure why this is happening here, but this fix will get it going again.)

After experimenting for hours, I realized the best method would be to have the cell fracture addon cell fracture an object based on the force of an impact over a number of frames. The only problem is that this feature doesn’t exist so, screw it.

Ah, c’mon coolman. The feature DOES exist… more or less. You need Bullet Constraints!!!
Check out Jonathan Lampel’s tutorials, e.g. youtu.be/w_m81zF9WtY (he has a bunch of these – they will help you)

But even if I do get the fracturing to work, the compositing will not work. I have had countless people tell me this: “Just put the main block on a separate layer and only show that layer until the glass starts to break.” Well, if I can recall correctly, when an object hits a piece of glass, the shards of the glass don’t just appear everywhere.

You can do some tricks in post to get around this. I’ve covered it in one of my first tutorial series, the breaking coffee cup.
http://cgcookie.com/blender/cgc-courses/breaking-objects-with-the-cell-fracture-add-on/