I'm working with a lot of legacy 2D DXF drawings and the imported lines are not constrained.

jacob_luetkemeyer · July 2016

I'm wondering if there's a way I could generate constraints based on the geometry of an imported sketch. For example If i import a rectangle and change the length dimension, how do i make the rectangle to behave like a constrained rectangle instead of dimensionalizing just 1 line at a time.

mahir · July 2016

I'm not aware of any autocontstraint functionality at the moment. Maybe in the future? For now, you can just select everything and add a fix constraint. For the simple rectangle example, you can add a dimension to the two parallel lines adjacent to the side you're lengthening. That would apply an implicit parallel constraint and probably keep recangle rectangular.

jacob_luetkemeyer · August 2016

Thank you for your feedback! Although that would fix my problem with the rectangle, most of my DXF files are more complicated. My company has over 6000 dxf files that we would like to import into onshape. Most of which are not basic geometric shapes.
Not only are the lack of constraints an issue but we have double lines, points not connected with a gap of <.0001"
Re-working the sketches is at the time our best option but I'm hoping to find a more automated approach.

3dcad · August 2016

+1 for perfect 2d dxf/dwg handling in drawings

brucebartlett · August 2016

+1 for improved dxf import into the sketcher.

@dave_cowden posted in another thread that he had worked out a solution to get better quality DXF files into Onshape for a featurescript library he's work on, this maybe of some help but ultimately we want this in the standard issue of Onshape.

dave_cowden · August 2016

Yes, i solved the not matching problem-- I had to to import like 1000 DXFs. The problem, I found, comes in with the fact that DXF represents arcs as center/start-angle/end-angle. this leads to the possibility of errors, because the end points in the adjoining segments are slightly different in the file, and you get precision problems.

jacob_luetkemeyer · August 2016

@dave_cowden I've seen the feature script for the profile generators and I'd like to say that's a fantastic tool and an impressive use of featurescript. Now if I could only get my 6000 DXF files into OS without going through generous amounts of time rebuilding the drawings. If there is any featurescript or external tools that someone could direct me to it would be a huge help. Simply stated, there needs to be an automated way to "clean up" the DXF files we import.

dave_cowden · August 2016

Ha, yes there is. I have written such a tool. I did about 2k of them to do the profile generators. Why dont you send me a PM and we can work out the details. I'm sure we can work something out.

lougallo · September 2016

@jacob_luetkemeyer Currently we do not try to recreate constraints upon import. I have added you to the improvement.

stvnvl_8501 · July 2023

any news on this? an easy way to add constraints to imported 2D drawings would prove very handy (even if it's an "at your own risk") option ;-)

dave_cowden · July 2023

Hi @stvnvl_8501,
The code I wrote did not solve the problem by allowing added constraints. That would indeed be cool. I was simply importing the dxf, and then converting individual line segments and arcs with almost matching endpoints to polylines and then trying bto close them. In practice, I found that the dxfs exported for 80/20 and many standard steel profiles needed this treatment.

What you ended up with in in shape was still a completely unconstrained sketch.. it just had the end points connected correctly.

I'm working with a lot of legacy 2D DXF drawings and the imported lines are not constrained.

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