DXF file scale setting

[mindflow]

Hi,

I have completed modelling one part afterwards, I have converted it into " Shape2D View".
I exported that file as .dxf and saved.

When I am opening that file and checking dimensions, all are 25.4 times more than that of original one.


Please help me with it.


Thanks,
MS

[openBrain]

Hi,

This is clearly the ratio between mm and in (1 inch = 25.4 millimeters).
Check the units you use for both original drawing and DXF import.
It's a common trap as DXF doesn't manage units.
In any case, you can solve your problem with the ratio setting in the Import-Export preferences of FreeCAD.

[mindflow]

Hi,

Original drawing is in mm.
I'm imported it in e-drawing software and opened.

There it is multiplies 25.4 times.

I have checked any unit options in it. But couldn't get any.

Any suggestions ?


Thanks,
MS

[openBrain]

I guess e-drawing considers by default DXF to be encoded in inches.
I don't know a lot about e-drawing. Perhaps there is an option to tell it the default unit to be used.

Are the dimensions correct if you import your DXF back to FC, or in another tool as LibreCAD ?

[mindflow]

I have imported back to FC & dimensions are same.

[openBrain]

Same as original or as in e-drawing ?

Could you provide both FCstd and DXF files ?

[mindflow]

Hi ,

I have attached .dxf file.

FC file too big,couldn't attach it.

[openBrain]

Hi ,

I have attached .dxf file.

FC file too big,couldn't attach it.

Without the FC file and any information, I have nothing to compare to...
Anyway, both in FC and in LibreCAD, the surrounding square shows a side dimension of 65 mm. Is that correct ?

[openBrain]

Ping

Yorik, as DXF importer expert ( ), I got the following bug with the new importer (while old python importer works well) with the top side file provided above by mindflow :

DXFnewImport.png (8.48 KiB) Viewed 8612 times

DXFoldImport.png (6.71 KiB) Viewed 8612 times

Maybe you can confirm and open a bug tracker if needed.
-----------------
OS: Ubuntu 18.04.1 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15521 (Git)
Build type: Release
Branch: master
Hash: 6cdeab9c1469a41f24ae5e8fa9091c9bdfbb90db
Python version: 2.7.15rc1
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: French/France (fr_FR)

[wandererfan]

I have completed modelling one part afterwards, I have converted it into " Shape2D View".
I exported that file as .dxf and saved.

When I am opening that file and checking dimensions, all are 25.4 times more than that of original one.

The Dxf spec is dimension-less until version R2000/AC1015. The FreeCAD legacy exporter only does R12 and the newer exporter only does R12 and R14.

The app that reads the Dxf file (e-drawing) is supposed to map the dimension-less input into the desired units, but some (many? most?) apps just interpret incoming dimensions as inches.