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Full Version: Moi3d dfx export issues

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From: bemfarmer
26 Sep 2022   [#2] In reply to [#1]
Hi Matadem

I do not have SheetCam or know much about it, but did a little google searching:
DXF from other software seems to also have scaling issues:

CrossFire PRO
May '20
it may be the way you are saving the file from fusion do not export to a .dfx file. Instead right click on the box it will be on the left side of the sketch under “Origin” “Sketch” this will bring up a menu and you will see save as a dfx. Click on that and save the file as a .dfx and the open that file in sheetcam. If you export the file it will be off in dimension…

(MoI has a Save AS dxf, and also an Export to dxf. (I do not know what the difference may be, if any.)

- Brian

Old MoI posts, 2007:
From: BurrMan
26 Sep 2022   [#3] In reply to [#1]

When exporting from MoI what are you setting options as? 1 unit in MoI = ??? Etc….

Are you drawing in MoI from the start in cm? (MoI has an option to scale on unit system change which can be unticked also. So if you are changing units for the export, it could be goofing there…)

Try resetting the sheetcam custom scaling dialogue back to 25.4 then getting out of the custom and use the inch or metric options. To match MoI export settings.

Sounds like sheetcam is reading it as mm…

So you can also convert to mm in MoI before export.

Or set scale factor of “1 MoI unit” in export dialogue to readout the other end scaled to the mm 10 factor

From: Michael Gibson
27 Sep 2022   [#4] In reply to [#3]
@Burr -

You wrote:
> When exporting from MoI what are you setting options as? 1 unit in MoI = ??? Etc….

That option is for output to a printer page result, it's used for PDF, AI, and SVG output.

MoI's DXF export writes to model space entities, not "paper space" so it doesn't have that same option.

- Michael
From: Michael Gibson
27 Sep 2022   [#5] In reply to [#1]
Hi Matadem,

> I am setting up sheetcam software right now...
> However when drawing in metric size a rectangle of 121.4cm x 243,8cm and when I try to export
> a dfx file from Moi 3d it comes up too small when I import in sheetcam.
> Sheetcam has an option to import metric, inches and custom.

Can you please post an example file that is not working for you? Please post both the .3dm file and the .dxf file.

That way I can check a couple of things.

When MoI writes out a .dxf file, it sets the unit system in the $INSUNITS header variable and many programs will check there and use the units that are set there but not all programs do that.

Thanks, - Michael
From: Michael Gibson
27 Sep 2022   [#6] In reply to [#2]
@ Brian,

> (MoI has a Save AS dxf, and also an Export to dxf. (I do not know what the difference may be, if any.)

The difference is that Export is short for "Export selected objects" - it writes only the selected objects out to the file you specify.

"Save As" on the other hand does all objects not just selected ones.

- Michael
From: bemfarmer
27 Sep 2022   [#7] In reply to [#6]
Thank you Michael,

I'll second Burr's 1:25.4 setting in SheetCam, indicates 1 inch = 25.4 millimeters. It seems that sheetcam expects or relates millimeters and inches. (or custom)
So using cm in MoI dxf export/save accounts for a scale factor of 10.
The small portion of the scale factor, perhaps ~ 0.16 +/-, seems to be some typical problem with scale in Fusion, a different Cad than MoI.
A 2020 Adobe Illustrator version had some recurring scale "bug" also.
It is funny to me that Illustrator keeps reintroducing the same(?) scaling "bug".

I have no idea why Save dxf might be better at scale than Export dxf, or if there is no difference in MoI.
Hopefully an example .3dm will be supplied, for testing.
(I'll resist making more comments, due to lack of knowledge :-)

- Brian

Ok, one more link, re Inkscape scaling problems:

I've read that the 2018 version of dxf is the one to use for dxf.
Quote: "DXF and STL are both very popular CAD file formats. The other thing that they have in common is that they don't specify the units. The amount of money and time that has been wasted in the world because of this is insane.
Make sure to tell whomever is importing a DXF what units were used for exporting. As an extra check, add some reference feature and call out that it's 10mm (or another appropriate round number) long."

Onshape always exports with the dimensions set to that the document is set to - to make sure I'm making sense, if I have a line in my drawing or sketch that has 500mm, the resulting DXF will say 500 (no unit) then in that $INSUNITS header it will say "1" for inches, so some software will load that line as 500 inch.
From: Matadem
27 Sep 2022   [#8]
Good day.
It seems when drawing in 1200mmx2400mm Moi will export and import in sheetcam just fine.

but not when drawing in cm. 120cmx240cm

Attached the file drawn in cm and a pic how small it turned out in sheetcam
the red square would be the material with a size of 48"x96"

and a pic of one drawn in mm attached as well.

Thank you!

export in cm.3dm

Image Attachments:
import in cm.jpg  import in mm.jpg 

From: Michael Gibson
27 Sep 2022   [#9] In reply to [#8]
Hi Matadem, thanks for posting the file.

It sounds like you have found the solution - for export into Sheetcam you should set your units in Moi to mm before you make your DXF export.

When MoI writes out a .dxf file, it does set a property in the .dxf file called $INSUNITS which many programs will look at to know what unit system the DXF file should be processed as. You may want to contact Sheetcam tech support and ask them to also look at that $INSUNITS setting in the .dxf file so they could handle importing a DXF file with cm units set in it.

Another option is that it looks like Sheetcam has a "custom" setting for how to process the units in the DXF file. If you have generated a DXF file that is in centimeters you can probably use the "custom" setting in Sheetcam with the right scale factor put in to make it load in ok. Sheetcam tech support can probably tell you what scale factor you will need to do it that way.

- Michael

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