How-to guide · how to overkill duplicate objects in autocad

How to remove duplicate objects with OVERKILL

DWGDXFFree1,058 words

By Sumana Kumar · Published 15 Feb 2024 · Updated 15 Feb 2024

Duplicate geometry is one of the quietest problems in CAD. Two lines drawn exactly on top of each other look like one, but they double the entity count, throw off areas and hatches, and make a drawing heavier than it should be. They creep in from repeated copy-paste, from exploding blocks, from sloppy tracing, and from merging drawings made by different people. OVERKILL is the command built to hunt them down.

OVERKILL deletes geometry that is duplicated, and optionally combines partly overlapping or collinear objects into single clean entities. Used well it can dramatically tidy and shrink a drawing in one pass; used carelessly it can quietly delete things you wanted. This guide shows how to run it, how to set its tolerance and options so it removes the right things, and the checks that keep it from doing damage — especially before you save a cleaned-up block back into a reusable library.

Step 1 — Select the objects to clean

Type OVERKILL and press Enter. AutoCAD asks you to select objects. You can window the whole drawing (type ALL then Enter) or pick only the area you want cleaned. Limiting the selection is often wiser on a large drawing — clean one region, check the result, then move on — because it keeps the change reviewable.

Press Enter to finish selecting. The Delete Duplicate Objects dialog opens, where all the real decisions are made. Nothing is deleted until you confirm in that dialog, so you can open it, read the settings, and cancel safely if you change your mind.

Step 2 — Set the tolerance

Tolerance is the single most important setting. It tells OVERKILL how close two objects must be to count as duplicates. A tolerance of 0 (the default) deletes only objects that are mathematically identical — the safest setting, and the one to start with. A small positive tolerance treats near-coincident objects as duplicates too, which is useful for cleaning imported or traced drawings where points do not land exactly.

Raise the tolerance cautiously and in small steps. Too large a value will merge or delete objects that are genuinely separate but close, such as parallel lines a hair apart in a detail. When in doubt, run at tolerance 0 first, then increase only if duplicates remain.

Step 3 — Choose what OVERKILL ignores

The dialog lets you decide which properties make two otherwise-identical objects 'different'. By default OVERKILL respects layer, colour, linetype and other properties, so a line on layer A and an identical line on layer B are kept as two objects. If you tick 'Ignore' for a property, OVERKILL treats objects as duplicates regardless of that property and keeps only one.

Be deliberate here. Ignoring layer, for example, will collapse duplicated geometry that you deliberately placed on different layers — sometimes what you want, sometimes a disaster. For a routine cleanup, leave the property checks at their defaults so OVERKILL only removes true twins.

Step 4 — Handle overlapping and collinear objects

OVERKILL does more than delete exact copies. The 'Optimize segments within polylines' option cleans redundant vertices inside polylines. The options to combine collinear objects that partly overlap, and to combine collinear objects that end-to-end abut, turn fragmented lines into single continuous entities. These are powerful for tidying a drawing where one wall line was drawn in a dozen overlapping pieces.

These combine options change geometry, not just delete it, so review the result. They are excellent for cleaning busy linework but should be used knowingly — turn them on when you specifically want to consolidate fragmented lines, and leave them off when you only want to strip exact duplicates.

Step 5 — Run it and verify the count

Click OK to run. OVERKILL reports in the command line how many duplicate objects it deleted. A quick way to gauge the effect is to check the entity count before and after — select all and read the object count in the Properties palette, or note how the file size drops on the next save.

After running, visually scan the cleaned area and try a hatch or area measurement on a region that was previously misbehaving; duplicate boundary lines that broke a hatch will often now let it fill correctly. If anything important vanished, UNDO immediately and rerun with a tighter tolerance or fewer 'ignore' options.

Pitfalls to avoid

The biggest mistake is running OVERKILL with a high tolerance on a whole drawing without checking the result — it can silently delete close-but-distinct geometry, and on a complex sheet you may not notice until much later. Always start at tolerance 0 and keep UNDO ready.

Second, watch the property 'ignore' settings: ignoring layer or colour can merge geometry you intended to keep separate. Third, OVERKILL works on geometry, not blocks — it will not look inside a block reference, so duplicates living inside a block need to be cleaned in the block editor. Finally, run AUDIT and PURGE after a big OVERKILL pass: removing duplicates often leaves the drawing lighter and cleaner, and purging clears any now-unused definitions before you save the file or push it back to a shared library.

Free download

Browse the full library — DWG & DXF, no signup.

Download CAD blocks

Questions

Frequently asked

What does the OVERKILL command do in AutoCAD?+

OVERKILL deletes duplicate geometry — objects drawn exactly on top of each other — and can optionally combine partly overlapping or collinear lines and arcs into single clean entities. It is the standard tool for cleaning duplicate linework from a drawing.

What tolerance should I use in OVERKILL?+

Start at 0, which removes only mathematically identical objects and is the safest setting. Increase the tolerance in small steps only if near-coincident duplicates remain. A high tolerance risks deleting objects that are genuinely separate but close together.

Why didn't OVERKILL remove my duplicate lines?+

Most often the duplicates differ in a property OVERKILL respects — they sit on different layers or have different colours, so it keeps both. Tick 'Ignore' for that property in the dialog, or check the lines are not actually inside a block, which OVERKILL does not look into.

Is OVERKILL safe to run on a whole drawing?+

It can be, at tolerance 0 with default property settings, but review the result and keep UNDO ready. Higher tolerances or 'ignore property' options can delete geometry you wanted. Cleaning region by region on complex drawings is safer than one whole-file pass.

Related downloads