Help How to simulate Planet gravity

[josemendez]

i want to know the box center position

That's neither the solver's position, nor the rope's position. That's the rope's center of mass.

To calculate the center of mass of a deformable object, simply do a mass-weighted average of all particle's positions. You have sample code for this in the scripting section of the manual: http://obi.virtualmethodstudio.com/manua...icles.html