Unabled adding a box to an occupied cell
Unenabled adding voxel when blockLeft <=0
return bug of can go directions fixed
Merge branch 'yifei' of https://github.com/yutongp/RaiseMeUp into ypei
Merge branch 'xinbweng' of https://github.com/yutongp/RaiseMeUp into ypei
ball can move !!!!