There are five Group Options for MEP Elements that include:

  1. Cid
  2. Length
  3. Size
  4. Service
  5. Specification. 

In the Renumber Options dialog box, the steps to renumbering fabrication elements are as follows:

  1. Specify the Start Number for the renumbering sequence.
  2. Click the checkbox to renumber based on Group Options.
  3. Specify the group(s) to renumber by.
  4. Click the OK button to close.

In Revit:

  1. Select the fabrication elements to renumber.
  2. Click the Finish button in the Options Bar after the desired elements are selected.

  1. Item Numbers will be changed:

  1. If two elements match in Group Options, they will be numbered the same