Hi, I would like to select all instances of a block, and put a new block on top of them using the same properties (insertion, rotation) but am unsure how to do this
That was nearly there, I have removed the delete original block line as I wanted the original to remain, had a little bit of tinklering with the rotation to work with our set up, 0 degrees = north and clockwise rotation. Now I can have a fiddle to get the blocks into the correct layer. Thanks heeps.
You can also try this without using any lisp routine.
1. Edit existing block A with Block Editor. Save the block definition as Block B
2. Edit existing block A with Block Editor again. Insert Block B and remove all other objects.
3. Insert Block C (the one you want put on top of Block A)
4. Close block editor, select all instances of Block A (use "Select Similar") and EXPLODE they all.
5. Purge Block A. Rename Block B to Block A.