Small Bodies Fall Through Ground

[wangleburt]

I've been searching the forums for hours, but I can't seem to find anything about this... I have a fairly simple physics simulation at the moment, where there's a big trimesh representing my city, and then when you click the mouse a box is created with some velocity that gets thrown forwards and eventually gravity makes it hit the ground. The problem is that frequently these boxes will just pass right through the ground without detecting collision

At first I thought it might just be that when the move too fast they miss the collision, but it even happens when they're not moving very fast at all (e.g. when I just drop the box from about a meter off the ground).

Through trial and error I managed to narrow it down to being reliant on the size of the boxes. If I make them bigger, I don't get any of these problems. They're not particularly small though to begin with though, about .5 meters length, and .2 meters width and depth, well within the size range that Bullet assumes for moving objects. Does anyone have any suggestions for how I would solve this?

[wangleburt]

Really? No one has ever had a problem with this before?

[sparkprime]

probably tunneling -- try decreasing the step size, can also use damping to stop the box going too fast


also could be due to broken triangle mesh data if it always occurs in the same place