DXF Import Comparison (Rhino, TurboCAD, BobCAD, DeltaCAD)

[yankeepapa]

Greetings-

To test PartWorks with various CAD packages I have available, I created a simple DXF file containing only a circle with a 1.8" diameter. The results of PartWorks operation were as follows:

Rhino: PartWorks showed 1.799" diameter
TurboCAD: PartWorks wouldn't load; DLL error
BobCAD: PartWorks wouldn't load; no error
DeltaCAD: PartWorks showed 1.811" diameter

I am not trying to say that PartWorks has an issue -- rather that there is an issue somewhere and I would like to find out whether it's PartWorks or the particular CAD software I'm using. Rhino gave the closest results, but was not 100% on target.

Has anyone else had similar results?

-David

[ed_lang]

Hi David,

To add to your post, I just tried the 1.8" circle in Corel X3 and exported it to PartWorks. PartWorks inported a 1.8" circle.

Since I do not have the other CAD packages you tested I cannot try out those but Corel X3 works just fine.

I can also say that Corel 12 works fine as well as I get signs from a sign shop to route all the time and they use Corel 12.


Try different versions of the .EPS file to see if you hit on one that works for you.

[yankeepapa]

Ed-

I looked at Rhino (my current front-runner choice), and it doesn't have the ability to save .EPS files. Part of the reason I'm leaning toward Rhino is it's scripting language and available plug-ins.

Perhaps there are some Rhino settings I'm missing?

Maybe I'll try and download a demo version of Corel X3 and see if I can reproduce your results.

-David

[tony_mac]

Hi David,

PartWorks / VCarve Pro will not open / import the latest AutoCAD 2007 DXF files, which maybe the default option for some of the CAD packages your are testing.

Most CAD packages offer the option to export designs as older R12 or R14 DXF files, and these are supported in PartWorks / VCarve Pro.

Tony

[dana_swift]

David, thats an interesting experiment! So I tried it.. I used Intellicad (an Autocad clone) and generated a 1.8" circle. To be sure it really did I checked the properties in the CAD program.

Then I saved it as ASCII DXF.

First I looked at the DXF to see what was saved:
AcDbEntity
8
0
100
AcDbCircle
10
0.0
20
0.0
30
0.0
40
0.9
0

Note the next to last number is 0.9 which is the correct radius for a 1.8" circle. So.. the cad program did its job correctly. I suggest you check the dxf files you are getting from these various cad vendors and see if they are outputing the circle parameters correctly. Only if they are ok, is it worth checking the result in partworks.

That done- I checked it in partworks and the result is exact 1.8". So I am quite curious as to why you get any other value from other cad vendors.. I am highly suspicious of the DXF implementations of the various cad programs.

For those who love paper work, the current spec for the DXF file is published by Autodesk and is a free download. Very very tedious reading! But it is the absolute reference for whether a given cad program is putting out correct data.

How tolerant should a software vendor be for malformed input data?

It was interesting to repeat your experiment at any rate. Thanks

D

[yankeepapa]

All-

I decided to cross compare CAD packages to see if the DXF files generated by each could be opened by the others. I'm not done yet, but I selected TurboCAD as a starting point to see if it could open the Rhino and DeltaCAD files. It (TurboCAD) opened the files, showing the sizes portrayed by PartWorks (i.e. 1.799" and 1.811", respectively). It would appear that the DXF file is where the inaccuracies lie -- not with PartWorks.

-David

[gabepari]

I just generated a .dxf with a 1.8" dia circle using Rhino. Checked the .dxf with notepad, and sure enough, the radius was .9

Maybe you are compounding errors when you "save as" .dxf ?? (ie you have a setting wrong)

Open up the .dxf with a text editor and look for "AcDbCircle", a couple of lines down will be the radius of the circle. It "should" read .9 no matter what generated it.

Gabe

[yankeepapa]

All-

Well, I've learned some things. First, I *can* save files via TurboCAD to a previous format of AutoCAD. This allows the files to be loaded into PartWorks.

Also, I learned I *can* save precise data via Rhino. It helps if you have "snap" properly set.

This has been interesting. I should be happy that (at least some of) the issues were with me. I am the piece of the system most easily corrected.


-David

[paul_z]

David,

There is an issue with Rhino and arcs when exporting as dxf and then importing into Parts Works/V Carve. The guys at Vectric helped and we found that using the 2004 Polylines option seemed to eliminate the problem.

Paul Z

[scottcox]

I use TurboCad Pro v14 and when I save as dxf, V-Carve Pro v4.6 doesn't import. When I save as eps, it imports but I usually have to clean it up by rejoining vectors. Tedious to say the least.

[knight_toolworks]

I don't have many problems with a little older version of turbocad. but you need to make sure all the little details are done in each program to get a good import. like exploding the curves and and a few other details to get a good import.