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Automated Multi-Polyline Area Calculator for AutoCAD | TotalArea.lsp

ByCADAuthority Team

Program Description

TotalArea.lsp is a robust and high-precision AutoLISP utility designed for architects, civil engineers, and surveyors. Unlike the standard AREA command, which requires selecting objects individually, this script allows users to batch-calculate the total area of multiple closed polylines simultaneously.

Built with advanced Visual LISP (VLISP) error handling, the tool automatically filters for closed geometries and provides a consolidated report via a clear dialog box. Whether you are calculating Floor Area Ratio (FAR), site coverage, or landscape zones, this script eliminates manual summation errors and significantly accelerates your CAD workflow.

In real production drawings—especially large master plans—manual area accumulation is where mistakes creep in. This tool removes that risk and standardizes the process across teams.

Why Not Use the Native AREA Command?

The built-in AREA command in AutoCAD works, but it slows you down in real projects:

  • Requires manual object-by-object selection
  • No automatic validation of closed geometry
  • No built-in batch reporting
  • Easy to miscount or skip entities under pressure

For quick checks, it’s fine. For deliverables, it’s not reliable enough.

Reference: https://help.autodesk.com/view/ACD/2024/ENU/?guid=GUID-0D5D2A06-4C7C-4F35-B714-9D7E6A0C2F5A

Full AutoLISP Program

(defun c:TOTAREA (/ ss i ent obj totalArea validCount areaResult)
  (vl-load-com)

  (setq totalArea 0.0
        validCount 0)

  (prompt "\nSélectionnez les polylignes fermées : ")

  (if (setq ss (ssget '((0 . "*POLYLINE"))))
    (progn
      (setq i 0)
      (while (< i (sslength ss))
        (setq ent (ssname ss i))
        (setq obj (vlax-ename->vla-object ent))

        (if (and (vlax-property-available-p obj 'Closed)
                 (= (vla-get-Closed obj) :vlax-true))
          (progn
            (setq areaResult
                  (vl-catch-all-apply 'vla-get-Area (list obj)))

            (if (not (vl-catch-all-error-p areaResult))
              (setq totalArea (+ totalArea areaResult)
                    validCount (1+ validCount))
              (prompt "\nErreur lors du calcul d'une surface.")
            )
          )
          (prompt "\nAttention : objet non fermé ignoré.")
        )

        (setq i (1+ i))
      )

      (alert
        (strcat
          "Calcul terminé !\n\n"
          "Objets valides : " (itoa validCount) "\n"
          "Surface totale : " (rtos totalArea 2 4)
        )
      )
    )
    (prompt "\nAucun objet sélectionné.")
  )

  (princ)
)

You can download the script here

Step-by-Step Guide

Load the Script

Type APPLOAD in the AutoCAD command line, locate your TotalArea.lsp file, and click Load.

Initialize the Command

Type TOTAREA and press Enter.

Select Objects

Use a window or crossing selection to highlight your drawing. The script is smart—it automatically filters your selection to include only polylines.

Process Data

Press Enter to confirm your selection. The program internally verifies each polyline to ensure it is mathematically closed.

Review Results

An instant dialog box appears, displaying:

  • Total number of valid objects processed
  • Total area, calculated to four decimal places

What Happens Behind the Scenes

This is not just a loop with vla-get-Area. The script handles real-world issues:

  • Ignores open polylines
  • Skips problematic entities without stopping execution
  • Validates object properties before accessing them
  • Prevents fatal errors in mixed or dirty drawings

You can run it on full site plans without babysitting the selection.

Optimization & Technical Reliability (SEO Insight)

What sets this version of the TotalArea AutoLISP apart is its bulletproof architecture.

  • Uses vl-catch-all-apply Prevents AutoCAD from crashing when encountering:
    • Corrupted geometries
    • Self-intersecting polylines
    • Invalid objects
  • Uses vlax-property-available-p Ensures compatibility across:
    • LWPolyline
    • Polyline
    • Different AutoCAD versions
  • Enforces closed-geometry validation No false area calculations.

This structure keeps results consistent and reliable, even in large-scale architectural or infrastructure drawings.

In production terms:

  • Cuts repetitive work significantly
  • Removes manual summation errors
  • Keeps calculations consistent across teams

Precision Considerations (Field Reality)

The script outputs:

(rtos totalArea 2 4)

That means:

  • 4 decimal places
  • Suitable for:
    • Large land parcels
    • Infrastructure layouts
    • Survey-level accumulation

If you’re working on:

  • Buildings → 2 decimals is enough
  • Land / parcels → 3–4 decimals avoids rounding drift

Best Practices in Production

  • Clean drawings before running (PURGE, OVERKILL)
  • Avoid mixing 2D and 3D polylines
  • Verify units (INSUNITS)
  • For reporting:
    • Copy results externally if needed
    • Or extend to table export

Reference: https://help.autodesk.com/view/ACD/2024/ENU/?guid=GUID-44B9ECFC-752C-4CC5-9DA3-84DBE5D8CFA3

Common Use Cases

  • Floor Area Ratio (FAR)
  • Site coverage
  • Landscape zoning
  • Parcel calculations
  • Right-of-way analysis

Anywhere repetitive area summation is required.

Limitations to Be Aware Of

  • Processes polylines only
  • Requires closed geometry
  • Does not include:
    • Circles
    • Regions
    • Hatches

These can be added, but at the cost of complexity.

FAQ

Does it work with 3D polylines?

Not always. Some don’t return valid area values. The script skips them safely.

Why are some objects ignored?

Because they are:

  • Not closed
  • Not polylines
  • Or fail safe area calculation

Can I include circles or hatches?

Not in this version. Requires extending the selection filter and logic.

Why use 4 decimal places?

To avoid cumulative rounding errors on large datasets.

Can this handle large drawings?

Yes. It scales well with full plans and large selections.

Can I export results automatically?

Not here. Next step is adding CSV or table output.

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