AutoCAD OVERKILL Command: Delete Duplicate Lines Safely
OVERKILL is the AutoCAD command that deletes duplicate and overlapping geometry. It removes duplicate or overlapping lines, arcs and polylines, and it combines those that partially overlap or touch end to end, according to Autodesk’s OVERKILL command reference. To run it, select your objects, type OVERKILL, and confirm the dialog. The part that takes judgment is the settings, because they decide what counts as a duplicate. This guide covers both.
TL;DR
OVERKILL deletes duplicate objects and merges overlapping lines, arcs and polylines. PURGE does something different: it removes unused named items such as layers and block definitions.
Run it from the Manage tab, Cleanup panel, or type OVERKILL. Select the objects first, or press Ctrl+A to select everything.
The dialog lets you set a tolerance and choose which properties to ignore, such as layer, color or lineweight. Those choices decide what gets deleted.
Always save a copy before a cleanup pass and check the result before you send the file on.
Use the command line version, -OVERKILL, when you want the same options without the dialog.
Table of Contents
What OVERKILL actually does
Drawings pick up duplicate geometry in ordinary ways. Someone copies a wall and pastes it back in place. A consultant’s xref gets exploded and bound over your own linework. A survey is traced twice. Two lines sit on top of each other and look like one.
Autodesk’s Purge and Overkill guide lists what the command handles:
It deletes duplicate objects.
It removes arcs drawn over portions of circles.
It combines partially overlapping lines that run at the same angle.
It deletes zero-length polyline segments.
The same page explains why this matters. Overlapping, duplicate objects can increase file size, make objects hard to select or modify, and cause errors when you export a drawing. For fabrication work, overlapping lines can even lead to improper cuts. For an architectural drafter, the day-to-day symptoms are simpler: you click a line, delete it, and a line is still there.
Which objects it works on
The command reference names lines, arcs and polylines as the objects that get removed or combined. The search results for this topic also mention circles, splines and ellipses as candidates for exact-duplicate removal. As a practical rule, treat linework as the target and do not expect OVERKILL to tidy text, hatches, dimensions or block contents. Those need different tools and a different eye.
OVERKILL vs PURGE
The two are often mentioned together, and the order matters. OVERKILL removes duplicate or overlapping lines, arcs and polylines. PURGE removes unused named objects, such as block definitions and layers, as the Autodesk guide puts it. One cleans geometry, the other cleans the drawing’s database.
We usually run OVERKILL first, because removing geometry can leave layers or other named items unused, and PURGE can then clear them. If you want the full safe sequence for the second half, our 5-step safe AutoCAD purge workflow walks through it, including the SaveAs and AUDIT steps.
How to run OVERKILL step by step
Save a copy first. Use SaveAs and give the file a clear suffix, for example “_pre-overkill”. Overkill is undoable, but a copy costs nothing and protects you if you save and close before noticing a problem.
Select the objects. Autodesk’s support article on using OVERKILL says to select objects, using Ctrl+A if you want everything. For a first pass on a busy drawing, a selection window over one area is safer than selecting everything.
Start the command. Type OVERKILL on the command line. You can also go to the Manage tab, then the Cleanup panel, and choose Overkill, as the Purge and Overkill guide describes.
Check the dialog. The Delete Duplicate Objects dialog opens. Review the tolerance, the ignored properties and the polyline and combine options before you accept anything. We cover each below.
Click OK. AutoCAD reports what it removed on the command line. Read that message. A count that is much larger than you expected is a signal to undo and recheck your settings.
Inspect the result. Zoom in on areas you know well, run a quick selection on a layer, and plot a test sheet if the drawing is going out.
If you type OVERKILL in a localized copy of AutoCAD and the command name does not match, entering _OVERKILL with the leading underscore works in any language version.
The dialog options that change the outcome
The defaults suit a lot of drawings, but the options are where control lives. Autodesk documents them in the Delete Duplicate Objects dialog box reference. They fall into three groups: tolerance, properties to ignore, and how objects are combined.
Tolerance
Tolerance sets how precisely two objects must match to count as duplicates. A tight tolerance catches only objects that really coincide. A loose one treats near-matches as the same object and can delete geometry that was deliberately drawn slightly apart.
A sensible approach is to start tight, run the command, and check the message. If you still see obvious doubles, loosen it a little and try again. Never loosen it on a drawing where small offsets are meaningful, such as detailed construction drawings at small scale, without checking the outcome.
Properties to ignore
By default OVERKILL compares properties as well as geometry. That is a safety feature: a line on a wall layer and an identical line on a dimension layer are not treated as duplicates. The dialog lets you tell it to ignore color, layer, linetype, linetype scale, lineweight, thickness, transparency, plot style or material during comparison, per the dialog reference.
Ignoring a property widens what counts as a duplicate. Two examples:
Ignore layer when a file has been through several hands and the same wall exists on two layers. Be aware that OVERKILL then keeps one and deletes the other, so you need to be comfortable with whichever layer survives.
Ignore color when objects are colored by object rather than by layer, and the doubles differ only in color.
If you are not sure, leave the properties unticked and let OVERKILL be conservative.
Combine options
The combine settings allow merging of collinear, partially overlapping or end-to-end objects. This is what turns a chain of short line fragments into a single line. It is useful for cleaning a drawing that was traced piece by piece, and it makes later trimming and offsetting more predictable. It also changes the object count, so if anything downstream relies on specific segments (a script, a data extraction, a quantity takeoff), switch combining off or test it first.
Polyline settings
The dialog includes polyline options to optimize segments or prevent breaking. The point to understand comes from the -OVERKILL command reference: when Optimize Polylines is set to No, OVERKILL examines polyline segments individually, and those segments may be deleted as duplicates of non-polyline objects.
In plain terms, a polyline that traces over a loose line can lose segments if you tell AutoCAD to treat it segment by segment. If your drawing mixes polylines and loose lines in the same place, check this setting before you run.
Using -OVERKILL on the command line
If you prefer to skip the dialog, type -OVERKILL with the hyphen. The command reference shows it offers the same kind of control: options to ignore properties, set the tolerance, and control polyline optimization. This is handy in scripts and in long sessions where you repeat the same cleanup, because the prompts follow the same sequence each time.
A cleanup routine that avoids surprises
OVERKILL is safe when you treat it as one step in a routine rather than a button to press at the end. This is the order we teach and use:
SaveAs a working copy. Keep the original untouched.
Unlock and thaw layers you want included. Objects on locked or frozen layers are not available for selection in the usual way, so check your layer states and decide what should be part of the pass.
Run OVERKILL on a small area first. Pick a corner of the plan with known doubling and see what the command reports.
Run it on the whole drawing with the settings you have confirmed.
Run PURGE to clear named items left unused.
Run AUDIT to check the database, then save.
Open the drawing again and plot a test sheet before it goes to the client or consultant.
Before you begin, Autodesk’s guide for its own practice file suggests copying the sample drawing to your Documents folder so you know you have write access. The same logic applies to your own files on a shared server: work where you are allowed to save.
Common problems and how to handle them
“It did not remove anything”
This is usually one of three things. The objects differ in a property you did not tell OVERKILL to ignore. The tolerance is tighter than the gap between them. Or they are not object types the command handles, for example text or a block reference. Check the layer and linetype of the “duplicate” with the Properties palette.
“It removed too much”
Undo straight away with Ctrl+Z, then go back to the dialog. The usual culprits are a loose tolerance, several ignored properties at once, and polyline optimization set so that segments are judged individually. Change one setting at a time.
“The file is still heavy”
Duplicate geometry is only one cause of file bloat. Unused layers and block definitions are another, and PURGE handles those. Imported or exploded details, hatches with huge point counts and proxy objects from other software also add weight. Our guide to common AutoCAD drafting mistakes and how to fix them covers several of these habits.
“Lines keep coming back”
If duplicates return every time you update a drawing, find the source. A repeated paste, a linked reference that is bound and re-bound, or an export routine that draws edges twice will recreate them. Fixing the cause matters more than cleaning repeatedly. Agreeing a drawing standard across the team stops many of these at the source.
Where OVERKILL fits in an architectural workflow
For architects and technicians, OVERKILL earns its place at three moments.
When you receive a file. A consultant’s or surveyor’s DWG often has doubled linework. Run the cleanup on a copy before you build on it, so your own trimming and offsetting behave.
Before you export. Doubles can cause trouble on export, as Autodesk’s guide notes. If you are sending geometry to a laser cutter, a CNC shop or another application, clean it first.
Before you hand a drawing over. A clean file is easier for the next person to edit. If you are comparing which tools suit this kind of drafting work, this overview of CAD drafting software for architects is a useful place to start.
If your next step is moving linework into a BIM model, tidy 2D geometry helps there too. Revit has its own cleanup logic, and our Purge Unused in Revit guide covers the equivalent routine on that side.
After years of training architects and technicians, we see the same pattern. People learn OVERKILL as a magic button, press it with every property ignored and a loose tolerance, and then lose linework they cannot account for. The command is not the problem. The problem is that nobody explained what “duplicate” means to AutoCAD. We teach it as a decision. What do you want to treat as the same object? Same layer only, or any layer? Exactly the same position, or within a small tolerance? Once you answer that, the dialog makes sense and the result is predictable. This is why our courses are project-based. You do not learn OVERKILL from a list of commands. You meet a messy drawing, clean it, and see what each setting does to real linework. That habit of working on a copy, checking the result and keeping a repeatable routine is what separates a drafter people trust with other people’s files from one who creates rework. If you want that kind of grounding across the whole of AutoCAD, with trainer support when you get stuck, that is exactly what we built our training around. Steve
Our perspective
Learn the whole cleanup workflow in context
OVERKILL is one command in a larger set of habits: layer control, blocks, purging, drawing standards and setup. Our AutoCAD Training takes you from beginner to expert through project-based lessons, with direct trainer support, lifetime access to the materials and a completion certificate. It is a one-off €79, and we back it with a money-back guarantee.
If you are earlier in your AutoCAD journey, start with getting started with AutoCAD, then see how BLOCK and WBLOCK keep your libraries tidy. If you want to see how a page set is built from the beginning, our architectural drawing setup guide is the natural next read.
FAQ
Does OVERKILL delete anything I cannot get back?
You can undo it immediately with Ctrl+Z. Once you save and close, the removal is permanent in that file. That is why we recommend a SaveAs copy before every cleanup pass, and a review of the command-line report before you continue.
How do I delete duplicate lines in AutoCAD without OVERKILL?
You can select and delete them by hand, but when lines sit exactly on top of each other, you cannot see which is which. Selection cycling can help on a small area, though it is slow. OVERKILL is the faster route because it compares objects and removes the extra copies for you.
What is the difference between OVERKILL and PURGE?
OVERKILL removes duplicate or overlapping lines, arcs and polylines. PURGE removes unused named objects, such as block definitions and layers, per Autodesk’s guidance. Run OVERKILL first, then PURGE, so that anything left unused is cleared.
Why does OVERKILL remove parts of my polylines?
If Optimize Polylines is set to No, the command looks at each segment on its own, and a segment can be deleted as a duplicate of a non-polyline object, as the -OVERKILL reference explains. Undo, then rerun with the polyline setting that matches how your drawing was built.
Can I run OVERKILL on the entire drawing?
Yes. Press Ctrl+A to select everything, then start the command, as the Autodesk support article describes. On a drawing you did not build yourself, test on a small area first.
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