On 4/7/17 3:45 PM, Dushyant Sahoo wrote: > I am new to IMP. I am trying to pack a group of spheres inside a box. > The spheres inside each group have a fixed distance from its immediate > neighboring spheres. I am able to pack spheres with the constraint that > spheres inside a group have a minimum distance from all other spheres.

It would help to know where you are stuck. But IMP should definitely be able to do this, albeit rather slowly. And it's probably overkill to use IMP for a simple packing problem like this. But you should be able to set up each sphere with a restraint to keep it in the bounding box and then a number of harmonic distance restraints to other spheres, then run a simple MC optimization.

Ben