[OpenSCAD] Rendering problems with QCAD-created DXF file (was Re: CSG rendering broken in latest Mac OS X)

[Andrew Plumb]

Hey Ethan,

In QCAD the Select Contour [tc] command is handy for catching open  
paths and their location.  Then you can use the Trim [tm] command to  
join things up.

See the attached b3.dxf for the fixed martini part.

Andrew.

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On 5-Jan-10, at 10:19 PM, Ethan Dicks wrote:

> On Tue, Jan 5, 2010 at 10:09 PM, Clifford Wolf  
> <clifford at clifford.at> wrote:
>> Hi,
>
> Thanks for taking the time to have a look.
>
>> The layers "ellipse1" and "ellipse2" both only contain asingle  
>> ellipse
>> entity. When trying to extrude those you should get an error
>> message like:
>>
>>        WARNING: Unsupported DXF Entity `ELLIPSE' (1x) in layer  
>> `ellipse2' of `b3.dxf'.
>
> I have seen that error but it wasn't consistent (see below).
>
>> A (clean) patch for dxfdata.cc to also support the DXF ELLIPSE  
>> entity would
>> be welcome.
>
> I don't know if I understand the environment well enough, but I'm
> willing to at least look at the code.  I won't be able to build it to
> test changes anytime soon though, due to limitations in what
> environments I have to work with right now.
>
>> The layer "martini" produces the follwing error messages:
>>
>>        WARING: Open paths in dxf_liniear_extrude(file = "b3.dxf",  
>> layer = "martini"):
>>            15.83700  -11.02500 ...   14.21700  -19.26200
>>            14.40000  -18.98700 ...   16.00000  -11.00000
>>
>> Just zoom to the coordinates 15.83700 / -11.02500 and 14.21700 /  
>> -19.26200
>> and you will see that there is a line in your dxf that does not  
>> correctly
>> connect to the other lines of the path.
>
> I suspected as much, but I didn't "see" anything when I looked it over
> in QCAD.  I certainly was _trying_ to make a closed path.  I'll see
> what I can do to close that shape up and play with extruding that.
>
>> A pitfall with this is that OpenSCAD caches the results of parsing  
>> a DXF
>> file. So you will see the error message only the first time you  
>> compile the
>> design. When you recompile it there won't be an error message  
>> unless the
>> timestamp and/or size of the DXF file has been changed.
>
> That makes sense from what I've observed - I occasionally saw errors,
> but couldn't pin down how/where/when.
>
>>> (speaking of which, there are a number of typos in diagnostic  
>>> messages)
>>
>> patches (or simple lists with corrections) are very welcome.  ;-)
>
> That I'm sure I can help with.  I can do context diffs easily.  Should
> I post them or send them to you directly or is there another preferred
> technique?
>
> Thanks,
>
> -ethan
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