# How to build building that is made of small pieces - how to correctly put rigid body over rigid body?

I'm new to blender and actually amazed from the possibilities it provides. I successfully created a set of boxes (like domino tiles) that fall in a chain reaction. (Like in this answer: https://blender.stackexchange.com/a/7111/8260).
When I did this there was a tiny fall of the tiles (about 0.001cm) and very quickly they stood still.

OK, Now I want to build a +30 tiles height building (and see them fall :-) ), but even though I put the tile one over another with precise mathematical positioning they still have an initial shake, so a 5 floor tower stands, but a high tower just falls by itself.

The tower I am tring to build looks like this:
(this is an example of 5 floor tower, each floor has 2 vertical tiles and one horizontal)

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So my question is - how can I position this kind of building with 30 floors or more without get the "initial shake" when starting the simulation - I want the building to fall only when it gets hit.

AFAIK Bullet (the library blender uses for rigid body simulations) is designed more for real-time speed over accuracy, so you might have to use some tricks.

1. Select all the objects in the tower and enable Enable Deactivation and Start Deactivated in Properties > Physics > Rigid Body Collisions.

Then right click on each setting and select Copy to selected.

This will make it so the tower will not be simulated until another active rigid body comes near it.

2. Increase the number of simulation steps in Properties > Scene > Rigid Body World:

The higher this value is, the more CPU time is needed to calculate the simulation. However, higher values will also make the simulation more accurate.

## Result:

• Great answer. Also, i can't stop watching the gif @.@. – StarWeaver Dec 1 '14 at 10:27
• @StarWeaver lol There is also a smooth video version if you click on it (the gif) ;) – gandalf3 Dec 1 '14 at 20:13