[solved] Create dxf file with splines in an external application

General Chat
1

Hello Together,

I am on developing an airfoil manager. To use the airfoils in qcad, i implement an dxf export.

The airfoil can exported as:

  • Lines
  • Poligonline
  • Spline

Now i try to export two Splines to the dxf file.
One spline for the top side, one line for the bottom side.
Additional i try to export one line as the airfoil chord.

Unfortunately, only the bottom line is displayed, if i open the file in QCad.
Has anyone a little bit mor knowledge about dxf files and can help me?

Also i like to minimize the header.

Attached files:
DXF_Header
DxfHeader13.txt (28.5 KB)
dxf file with 2 Splines

Thank you and BR
Rainer

p.s. OS Windows or MAC, QCAD Professional V3.27

2

I can confirm that the file “A 18_2Splines.dxf” contains exactly one spline entity (i.e. one “SPLINE” entry in section “ENTITIES”).

3

Hello Andrew,

sorry i have attached the wrong file.
This is the correct file :
A 18_2Splines.dxf (32.5 KB)
Thank you and BR
Rainer

4

The new file shows two splines. One zero length and one which is 201.33970578 in length. No units used.

Husky-2022.02.10-01.png
Husky-2022.02.10-01.png524×284 5.39 KB

5

Correction:
1 Spline + 1 zero length line.

Before saving that could have been a Null-Line entity.
Only selectable with TA.
On reload those pop up as zero length lines at the origin angled 0 degrees.

Regards,
CVH

6

Hello Together,

In the file should be two Splines and one Line.
Unit should be mm.

First Spline starts on line 3948
Second Spline starts on line 4228
The Line starts on line 4508 ans should be from 0,0 to 200,0

LINE
8
0
10
0.000000
20
0.000000
30
0.000000
11
200.000000
21
0.000000
31
0.000000

What is wrong in the dxf file, that only the second spline is displayed and the line has the wrong length?

Thank you and BR
Rainer

7

A couple of things:

  • the file has multiple ENTITIES section for each entity (not sure if this is allowed, certainly not common)
  • In the chosen revision of DXF, LINE needs DB entries:
100
AcDbEntity
100
AcDbLine
  • Both splines use the same handle (ID) which would explain that only one is imported:
  5
38
8

I am not a specialist in this but this is how a line (0,0,0) - (0,200,0) looks like exported by QCAD in R13 dxf:

SECTION
  2
ENTITIES
  0
LINE
  5
39
330
279
100
AcDbEntity
  8
0
100
AcDbLine
 10
0.0
 20
0.0
 30
0.0
 11
200.0
 21
0.0
 31
0.0
  0

Further, if I export 2 random fitpoint spline there is no termination of the section between them:

ENDSEC
  0
SECTION
  2
ENTITIES
  0

I can copy both of the splines sections textual to the test file with the line … :wink:
… one by one. But I didn’t manage to include both at the same time. :frowning:
With copy/paste under QCAD from 2 trials to a new drawing file I get:
A 18_2Splines_v2CVH.dxf (66 KB)
Regards,
CVH

9

Hello together,

thank you for your Help!
With the Info from Andrew, i could fix my probelm!
A 18_2Splines.dxf (32.5 KB)
Thank you an have a nice weekend!

BR
Rainer