Finding overlapping geometry without manually checking every line

[indiancad]

In a complex 2D drawing, two or more lines may occupy exactly the same position. The drawing can look perfectly correct, but duplicate geometry can cause problems during area calculations, hatching, CNC preparation, and file conversion.

One useful command is OVERKILL. It detects and removes duplicate or overlapping geometry, with options to control how objects are compared.

However, running it with default settings may not always produce the desired result, especially in drawings with different layers, linetypes, or partially overlapping segments.

Do you routinely run OVERKILL before issuing a drawing, or do you prefer to identify and correct overlapping geometry manually? Have you ever found a problem caused by duplicate entities?

[SLW210]

I use a couple of LISPs.

 

 

[indiancad]

18 hours ago, SLW210 said:

I use a couple of LISPs.

 

 

That's a useful approach. Do your LISP routines also detect partially overlapping lines, or mainly exact duplicates?

[SLW210]

That depends on the LISP.

 

Check my GETLEN.lsp. as an example.

A new get length LISP - AutoLISP, Visual LISP & DCL - AutoCAD Forums

 

It gets perimeters and accounts for gaps and overlaps even in anonymous blocks. I made that due to SOLPROF profiles being a pain with the overlaps, etc..

 

So, sometimes a cleanup isn't required to get correct information, just a LISP or other code.

 

I have one somewhere, but there are a few online "OVERKILL"  type LISPs that work on blocks and sometimes better cleanup, something OVERKILL doesn't do all of the time.

 

But, OVERKILL does under normal circumstances do fairly well, so a first run with that, or a second run if the drawing needs a real flattening, best to do that first.

 

The waterjet/plasma cutter person at work does a lot of the work for those machines now, but I used to do all of it when those were first purchased. So I have done lots of cleanups for cutting. Luckily, most things I start are pretty clean except the SOLPROF and SOLVIEW/SOLDRAW objects. 

 

The software that came with the waterjet also can do some cleaning. So I have that as well.

[CADhomie]

On 10/30/2026 at 11:22 PM, indiancad said:

In a complex 2D drawing, two or more lines may occupy exactly the same position. The drawing can look perfectly correct, but duplicate geometry can cause problems during area calculations, hatching, CNC preparation, and file conversion.

One useful command is OVERKILL. It detects and removes duplicate or overlapping geometry, with options to control how objects are compared.

However, running it with default settings may not always produce the desired result, especially in drawings with different layers, linetypes, or partially overlapping segments.

Do you routinely run OVERKILL before issuing a drawing, or do you prefer to identify and correct overlapping geometry manually? Have you ever found a problem caused by duplicate entities?

I work with 2D CAD drawings for protective foam packaging and CNC, so overlapping geometry is something I pay attention to. Duplicate lines can create problems downstream, especially when preparing closed profiles for cutting. I think it's worth teaching beginners to check their geometry early instead of waiting until export.