What Are Redline Drawings?

A redline drawing is any drawing in engineering construction that shows the viewer changes that have been made on a previously approved drawing. Red lines can be done with a red ink pen or any other tool. For 3D designs, AutoCAD’s RevCloud is a perfect tool for making a redline. For the most part, redlines are made after the completion of a project phase.

Construction Sequence of RedLine Drawings

  1. The contractor prepares the design
  2. Client approved the design
  3. Contractor produces a drawing based on the design approved
  4. The contractor submits the drawing with revision numbers
  5. Client approves, disapproves or comments on the drawings
  6. Contractor modifies drawings based on client’s reaction and resubmits
  7. If the client approves the drawings, it will be marked as (AFC), Approved for Construction
  8. Once the AFC is received, construction work will start
  9. If there are changes with respect to the final design structure, the contractor shows the changes by drawing redlines
  10. The Contractor’ Quality Assurance team analyzes and approves the Redlines.
  11. Redline alteration is submitted to the Client for comments/approval
  12. A clean design copy with new alterations is produced by the contractor showing Client’s comments
  13. The final drawing will show revisions
  14. All designs rights are owned by the client at the end of the process


The sequence we provided is a common sequence used by many construction contractors, albeit with few alterations. However, the sequence doesn’t matter as much as the purpose.


Getting a structural design right the first time is not always possible, but making alterations with Redline drawings makes for a feasible design. With Redlines, an average viewer can spot the point of changes and also understand why the changes were made in the first place.

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