Made DXF file on autoCAD - will not open on KLayout

[cw162]

Hello, I have a drawing I made in AutoCAD for a photomask in microns, attached here as drawing2 in the zipfile. Drawing2.zip

It looks like this

I need to open it in KLayout as that is the software in the cleanroom. However, I kept getting the "Coordinate value overflow" error.

I've tried to play around with the file/reader options for opening the DXF and the only database unit that works is setting to 1 um

but once it does get it open, it just looks like a giant purple circle and not my pattern,

Can anyone please help? I just want to open my file on Klayout

[Kazzz-S]

1. Introduction

My Work Environment

1. OS: Linux Mint 20.3
2. KLayout: 0.29.2 (source build)
3. CAD for DXF: QCAD Professional 3.30.1

Observations

1. At a glance, the DXF file size (300MB) looks too huge compared with the complexity of the shapes drawn.
2. I could reproduce the problems described above.
3. The diameter of the giant purple circle is 140 meters, which hides every meaningful shape!
   
4. I copied and saved a part of the design (ex. AREA 00) to another DXF, whose size is only 253KB.
5. Therefore, the original DXF file must contain plenty of invisible (and harmful for KLayout) data.

To be continued.

[Kazzz-S]

Cont.

2. Generating Leaner DXFs

• I selected ALL (selectable) items and copied them to an empty sheet to generate Drawing2A.dxf.
• The file size is reduced to 1/100 of the original one.
• I manually edited (described later) Drawing2A.dxf to generate Drawing2B.dxf.

To be continued.

[Kazzz-S]

Cont.

3. Drawing2A.dxf and Option-[1|2]

• With above Option-1, DXF ---> OASIS conversion was successful.
• However, one rectangle is missing, as shown below.

---

• With above Option-2, DXF ---> OASIS conversion was also successful.
• The rectangle appears, but is it OK?
• The rectangle consists of 1 closed poly-line and 4 individual lines.
• The latter lines are connected to a single closed poly-line while reading.
• Then, when converting to polygons (with inside-outside discrimination), 2 overlapping poly-lines cancel each other and disappear.
• This is a typical error when using a DXF-based CAD for photomask design.

To be continued.

[Kazzz-S]

Cont.

4. Drawing2B.dxf and Option-1

• I deleted the 4 individual lines to generate Drawing2B.dxf.

• With above Option-1, DXF ---> OASIS conversion was successful.
• The output is now OK, as shown below.

To be continued.

[Kazzz-S]

Cont.

5. Summary

1. I suggest first cleaning up the original design in DXF.
2. Or, using KLayout from the beginning would be better since the layout design is very simple.
3. Switching the reader options (as seen above) would help to detect potential errors.
4. All relevant files ===> GitHub1748.zip

Regards, Kazzz-S

[cw162]

Thank you very much for looking into the problem and troubleshooting! The problem was a lot more complex that I would have thought. Ill likely stick to Klayout for now as you suggest