CAD tip # 6216:

In some cases you will need to first create an auxiliar offset curve to the original linework with the OFFSET command.

In detail:

Use the "MEASURE" command if you need to array the blocks at a distance from one and other which you enter as part of the process. If you wanted to divide the path into a number of segments, and then array the blocks at the points at which the path divides, then use "DIVIDE". It works in the same way, only you choose the number of segments to split the path into as opposed to the length of each segment.

1. Create the block, the thing you want to array (the BLOCK command)
2. Draw the path, for example, an ellipse.
3. Use the command: MEASURE
   1. Select the object which forms the path
   2. Type "b" (for block) enter
   3. Type the name of the block you want to array enter
   4. Type or leave "y" in to align the block against the object enter
   5. Type the desired length of segment enter

Done.

(detail by "idiosyn85")