Begginers question on exports and dimensions

HI

Teaching myself librecad and run into one particular problem I cant figure out.  Whenever I export my features are 50% bigger in any app I import the DXF into then the measurements I have created them in. I'm working at 1:1 creating a small design 153mm across, feature when I export are approx 225mm across.

Now this looks like a setting issue somewhere but I just cant find it

Help! getting a little frustrated with this one now.

General factor and general scale are set to 1, and everything I can see is set to mm.  I'm going to be using this to transfer to a laser cutter and accuracy is quite important as its interlocking parts.  I have left clearance in the design but not much so I dont want to just reduce it by 50%

Thanks in advance!

can you upload a test case file to show this problem?

idmurp wrote

HI

Teaching myself librecad and run into one particular problem I cant figure out.  Whenever I export my features are 50% bigger in any app I import the DXF into then the measurements I have created them in. I'm working at 1:1 creating a small design 153mm across, feature when I export are approx 225mm across.

Now this looks like a setting issue somewhere but I just cant find it

Help! getting a little frustrated with this one now.

General factor and general scale are set to 1, and everything I can see is set to mm.  I'm going to be using this to transfer to a laser cutter and accuracy is quite important as its interlocking parts.  I have left clearance in the design but not much so I dont want to just reduce it by 50%

Thanks in advance!

idmurp wrote

 Whenever I export my features are 50% bigger in any app I import the DXF into then the measurements I have created them in.

Maybe its the app you are using and not LibreCAD ???

Hi

I tried in 2 different tools with the same error, I will upload the file this evening once I get home.

Cheers

Ian

puzzle_box_scale_test.dxf

File as requested

It still needs laying out and a bit of cleanup (dont judge me :p )

I'm not sure about what is the bug yet.

Could you give detailed steps to show the problem?

I just got the dxf opened here, but have no clue on the meaning of "export" or "50% larger", etc.
 

idmurp wrote

puzzle_box_scale_test.dxf

File as requested

It still needs laying out and a bit of cleanup (dont judge me :p )

When I measure in Librecad the biggest component is 153.9mm across, I created it by setting the size in mm of the circle when I created it.  

When I export to another format, or open in another cad program they are 50% bigger.  Problem is I need to export this into dxf, and then get it cut.  Im worried it will come out 50% bigger then I expected when I get it cut.

Is that clear?

I open your file in LibreCAD and draw a rectangle of 3120x1500
from -1000,-750 to 2120,750 and draw 2 dims, see attached screen capture:


I open your file in AutoCAD and draw a rectangle of 3120x1500
from -1000,-750 to 2120,750 and draw 2 dims, see attached screen capture:


The result is the same, then no problem with your dxf.

Another test, imported in Inkscape (in imput DXF dialog unset automatic scale)
and draw a rectangle of 3120x1500 all is ok:


In what programs you have trouble?

Cheers,
Rallaz

Could it be a matter of diameter/radius?

When I measure the biggest circle in the origin (X0.0, Y0.0), I get a diameter of 307.8.
If you enter 153.9 on creation of circle, LibreCAD creates a circle with a radius of 153.9 what results in a diameter of 307.8.
But 307.8 is 153.9 +100%.
Try to draw a dimension in LibreCAD or use the measure tools from info tool bar to verify this.

Can you please clarify the numbers. What is the desired diameter of this circle and what is the absolute diameter in mm of the exported circle?

Armin

HI

The 153mm is the diameter measured in librecad as below

However for example, when print previewed in the viewer it is significantly bigger, this is against an A4 sheet (210x297mm)



It wouldn't surprise me if this was my error.

Ian

Armin he's right.

Your circle have a 307.8 diameter.

See your screenshot:


And using "dimension->diametric" or "Info->list entities" :


About print preview screenshot:
Print scale 1:1
Circle bounding box 307.8 x 307.8
Paper dimension (A4) 210 x 297

Result: the circle is bigger than the paper

Tip: With "Modify->trim" you can trim a entity or extend it instead of redraw to complete arcs

Cheers Rallaz

OK....so the answer is, I'm a numpty.

oops

sorry for wasting your time!