If you have a physics object which gets into a situation where the amount of bounce causes a resonating motion, 9 times out of ten the object will fly through any object barriers you have placed and out of the scene.
This also happens if you have a moving object that hooks the element. It will in effect drag it out of the scene because of bounce resonance builds up in a small space.
This is a known bug.
I have seen it lessen if your static object is 2x as thick as your dynamic object minimum…
That sometimes is too much for your design so I get creative with invisible static blocks beneath my visible blocks as well.
Many years ago I had an analogous problem with a sprite-based animation engine; essentially, the sprite’s loc onscreen was updating too fast for the sprite-based collision detection to render and compensate for, so it would occasionally escape its boundaries.
The only workaround I was able to develop was to poll for the sprite’s anticipated location, determine if it was outside the bounding rect, and reset it to those boundary values if it was. That bypassed onscreen updating and collision-detection entirely and added an extra step at each frame iteration, but it did solve the problem.
I’m not sure how you’d go about doing an analogous thing in Hype. A frame action, maybe? One that checks the balls’ locations on each frame refresh?