LISP to replace copies of 3D Solid with a block

[Anonymous]

I am looking to either find or write a LISP that will allow me to replace 3dsolids with blocks.  Lets say I have a cube that is 1"x1"x1" and I copy it 50 times through my drawing.  I then decide to change that object to be a rectangular prism measuring 2"x3"x4".  Since I did not block the initial solid before I copied it, I can't now change one and have them all change.  Is there a LISP that exists or I can write that would allow me to select one of the objects I want to change, turn it into a block and then find all the objects with the exact same area, dimensions or what not and replace those 3dsolids with the block?  I am very new to LISP but this feels possible.  Any help or guidance is greatly appreciated.  I am not really sure where to even start.  

Thank You

[vladimir_michl]

Probably not only a Mechanical but a general AutoCAD question. In any case you can use a combination of two freeware LISP utilities - SolSimilar and Sel2BlkRef. See www.cadstudio.cz/freeware

SolSimilar selects all geometrically similar (identical) 3D solids. Sel2BlkRef automatically replaces all selected (e.g. from SolSimilar) DWG objects (2D or 3D) with block references of a single block (auto-generated). Try them - they might solve the problem.

Vladimir Michl, www.cadstudio.cz  www.cadforum.cz

[vladimir_michl]

and a screencast:

[video]