Ran across this short article I wrote several years ago to address an issue I'd run across several times. Not sure whether I'd posted it then, but in any case, here it is now...
It is sometimes required to enlarge or reduce the size of a set of objects without changing the size of the objects themselves (i.e., to change the distances between objects without changing the objects). Here's a way to do it...
1. The objects must be ACIS Solids. "Primitives" such as Spheres, Boxes, or the like, if created as Solids must be exploded to make them ACIS Solids.
2. In Options>ACIS, DISable "Allow axis scale."
3. Select all of the objects in the set, type the required value in the ScaleX field of the Inspector Bar and press Enter.
4. While the objects are still selected, type the required value in the ScaleY field and press Enter. Do not try to rescale X and Y simultaneously.
5. With the objects still selected, type the required value in the ScaleZ field and press Enter. Do not try to rescale Y and Z simultaneously.
Note that the scaling factors need not be the same for each axis.
To rescale the objects themselves without moving them:
Enable "Allow axis scale," select the objects, enter the desired rescale values in the Scale fields of the Inspector Bar, and press Enter. Leaving the objects selected, DISable "Allow axis scale" and proceed as above, using as the scale factors the reciprocals of the values in the first operation. (That is, if the selection had been enlarged by a factor of 2.0 when "Allow axis scale" was enabled, use a scaling factor of 0.5 after DISabling "Allow axis scale."
P.S. The white helices in the screenshot are simply to provide a frame of reference for anyone viewing it.