Problem with DXF export/import


#1

Hi everyone!

I have this very simple object that I need to export to DXF for my supplier that uses CAD but he says he cannot import it correctly so I went to check and in fact, when I import it back it is completely corrupted.

placa.skp (170.1 KB)

I’m using SketchUp Make Version 15.2.687 and option Export to DXF or STL. For importing I’m using extension FreeDXF v0.9.0.

I’ve tried all 5 different options, e.g, polyface mesh, polylines, triangular mesh, lines and stl. The first option keeps most of the object intact but adds some strange lines like it happens sometimes when for instance we intercept some complicated objects. As you can see I don’t have any hidden geometry lines that could explain this. The other 4 choices are even worse because with the exception of ‘lines’ the object just seems to vanish whenever I import it back.

This is what I see when I import the DXF that I previously saved with polyface mesh option:


DXF conversion trouble
#2

What should I see in your model? To me it seems completely OK.

A mesh is always triangulated, a polyface mesh can have its coplanar triangulated edges hidden, but they are still there. When you import a mesh, by default all the triangle edges are visible. The SketchUp Pro DWG/DXF importer has the option “delete coplanar edges” that will clean the import automatically - I don’t know how the Ruby script alternatives perform in this respect.

Anssi


#3

Which is obsolete. Update to 15.3.x, see the Release Notes page.


#4

Maybe I didn’t make myself clear. I need to export my drawing to DXF (or any other format) so it can be opened in CAD without added geometry of any kind. So for me this is not only abnormal but even worse it is not acceptable as the guy who is going to work on CAD has no idea which lines to delete. It’s nice to know SketchUp Pro has this option to “delete coplanar edges” but unfortunately it’s completely pointless as again, the import is going to be made in CAD.
Is there any other format, option, plugin, whatever, that allows compatibility between Sketchup (Pro or free) and CAD?

I’ve updated my SketchUp by the way.
Thanks!


#5

Was the model geometry grouped before export ?

The Community STL extension requires that a group be selected before export.


#6

No but the result is the same with or without grouping.
I’ve tried this other extension but the outcome is exactly the same.


#7

First a few pointers on your Model…
If the correct orientation is as your initial image… you have your Axes inverted.
They can be Reset, but then your geometry is miles from the Origin !
When viewed with Hidden Geometry ON there is no subdivision of the faces.


The native Pro 3d DXF exporter exports edges/faces fine, with no subdivisions.
If you import that DXF using the Pro version importer, then it arrives back in with its faces as expected - no subdividing - with OR without merge-coplanar option ticked. Free exporters/importers will often triangulate meshes when geometry is exported or brought back in. This is what you are seeing… Since you are using free-extensions, then you get what you get…
STL/DAE/etc exporters triangulate meshes, as do their equivalent importers.


#8

Thanks TIG. So basically if I understood correctly SketchUp Pro doesn’t create these artefacts whereas the free extensions out there, because they triangulate meshes, do. That’s a pitty. I wouldn’t mind paying for some extension that does this right but a SketchUp Pro license is way too expensive for me.

Is anyone aware off any such extension? What other options do I have for instance using different formats?


#9

The Community STL extension requires that a group be selected before export.

It has an option to export only the selection, but a selection is not required.


#10

save as file dwg version to dwg2000

hope it is useful


#11

I don’t have these options on SketchUp Make I’m afraid.


#12

And they are not presented that way even on SketchUp Pro.

He must be showing the Save As… dialog from AutoCAD.

What is important (from his post, I think,) is he is suggesting that the DWG v 2000 file format works best between SketchUp and AutoCAD.

(I do not know if that is really true.)


#13

I have not had problems for years working with the latest DWG/DXF file type supported by the SketchUp importer.

Anssi


#14

HI Dan,

I have the same problem exporting a Sketchup DXF or DWG drawing. I am using BobCad, and it imports with the same effect. I have cleaned up simple images, as the mesh is in a different color. I am able to select on the color and delete.
Also, all 2D images must be exported, while looking straight down. No ISO’s.

Additionaly, all my files import into BobCad at a different scale. I have to rescale each time. Does anyone have a different CAD program, that imports saved DXF files from Sketchup, into any CAD program without distortion?


#15

Hi Anssi,

What CAD program are you using to import clean SU DXF files into?

The best I can achieve is, not group the drawing, under options only select “edges” and I use release 2010. I am sure other releases will work as well, though the latest release will not. In BobCad, I have to change the line color from red, and resize. Basically, it only can come in, as if all lines were selected from a solid. If I wish to have a CAD file showing a 3D image, I have too planar each surface, which is to much work for larger drawings.

Can someone tell me of a program which imports saved SU 3D files into, and looks the same as it did, in SU? Need to know if it’s just my CAD program, or a SU issue, as I have never encountered this problem importing other DXF files.


#16

What SketchUp ? (Make or Pro)
What SU version ?
What bitness, if PC ? (32bit or 64 bit)

What exporter ? (SU native or plugin)
If plugin what version ?


#17

if that be the problem scale …
I often compare from one program to another, and the average will always be differences when imported or exported.
live how we take the proportion with wisely, because basically unchanged original scale so that the image of imports or exports unchanged form.
greeting


#18

Just a word of caution: don’t install AnyCad Exchange3D, ever! in my quest for a converter I tried many and then found this one that silently installed a Chinese Antivirus and it was a pain in the *** to get rid of it because all the dialogues were in Chinese! The bottom line is, there is not one single free converter out there that gets the job done without adding artefacts. FBX converter for instance isn’t even capable of converting FBX to DXF. Actually it makes some conversion but the result is a very small file totally meaningless. So it seems that all these formats have some serious issues that makes converting between them a daunting task, if not an impossible one. If someone disagrees please do tell.


#19

It makes no difference what version SU it is. I have tried them all, and
all with the same consistent outcome. The faces become broken up, with
multiple lines extending from one point.
This happens regardless of Mac, or 64 bit PCs. Not sure of 32 bit.

I now uncheck faces. This solves the corruption, though only imports into
BobCad as lines. I rescale, and finish my CAD from there. If I want a
colored CAD surface, I have to Planar the top surface, and extrude.

This works fine for 2D milling and routing. Make 2013 has DXF export,
though no way to transition back from 2015. I run 2015 Pro.

Best Regards,

Steve Clayton

Steve Clayton, Inc.
201 Rogue River Pky.
Talent, OR. 97540
541 535-4440 Ext. 707
www.steveclayton.com


#20

I usually use Autodesk software.

Here is a screenshot of a model of mine in SketchUp:

And here is a screenshot of the same as exported to 2010 DWG and viewed in hidden-line mode in Autodesk DWG Trueview (their free DWG/DXF viewer/converter):

The result doesn’t show triangulation. Perhaps BobCad doesn’t support polyfaces.

Anssi