Lads,
I’m stacking rigid bodies with box-colliders into a jenga-like tower. I have 9 blocks per level. The problem is that once I get higher than 7 or 8 levels, and play the game, the tower becomes unstable and buckles on it’s own. I’ve tried increasing the mass of the rigid bodies on the base level, but that only marginally helps, and ultimately the structure collapses again.
Anyway, stacking these rigid bodies is kinda central to my gameplay. Does anyone have any thoughts?
Thx,
Stef
I've worked pretty extensively with PhysX inside of Unity, so I can offer these possibilities to you:
1: Ensure that your Jenga blocks all are using a custom physics material, and that this material has a good amount of friction and NO BOUNCING (if your bricks are bouncing, any fluctuation in the simulation could cause them all to simultaneously bounce against each other and result in a mess).
Since you say your tower is buckling without you touching it, Static Friction is extremely important here (Static Friction is basically how hard it is to start an object moving). Dynamic Friction is important as well. Increase these values and you shouldn't see your tower shifting into pieces anymore.
2: The game I'm making right now is practically physics-based, and one thing I've learned the hard way after much iteration is that you may want to add a layer of behavioral programming into the blocks. You can't rely on the simulation to work the exact way you want it, so you may want to take steps to make sure it plays by the rules, such as putting all the blocks to sleep when the game starts and having them wake up in a rolling fashion, and seeing if it helps stability.
3: Even if it means starting over, you need to get your scale right. 1 unit is 1 meter according to the default gravity inside Unity. If you haven't followed a 1 unit = 1 meter philosophy and left your gravity at default, you'll have no idea why you're tweaking the settings you're tweaking or what to tweak them to. The fact that you decided to randomly fiddle with mass leads me to believe you might not have planned properly (but just a guess).
Let me know if this helps or if there's something specific you need to know about. Like I said, I've worked extensively with Unity's physics over the past few months so I'm pretty knowledgeable about solutions.
Also, as Will said, increasing Solver Iterations is a good (albeit brute force) manner of trying to make the physics engine comply and behave properly if all else fails.
Another thing to try is turn down your gravity in your “project settings->physics” if it’s set to -50, try -10
Hope this helps :),
also you could modle your bottem level exatly like the rest by Ctrl C when the objects are selected