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DXF format querries..!!!

Posted: Fri May 03, 2013 5:03 pm
by rakeshthp
I am trying to design and develop a DXF importer using C++. I have gone through the DXF references starting from version 2000 onwards. There are four things which have put the development on hold for me right now.

1) Handles for each entity. Are they really important? If so, then how are they related to other entities?

2) Entities such as ARC, POLYLINE, TEXT etc occurs in BLOCKS section and in ENTITIES section. What difference does these two sections make? Why not all the entities are placed in ENTITIES section?

3) What is INSERT entity? How does this work? Does it have any visualization (as it contains insertion point, scale and rotation factors)? If so, how is it represented graphically? As a point (as it contains only one point )?

4) I see that some points are in OCS and some are in WCS. How do I convert OCS to WCS? For this point I did some google research and didn't get much help, as most of them use auto-lisp for this and I am using C++.

Kindly learned people guide me, by clarifying these doubts.

Thanks in advance

Re: DXF format querries..!!!

Posted: Fri May 03, 2013 5:58 pm
by andrew
Are you using dxflib to parse the DXF input?

Re: DXF format querries..!!!

Posted: Sat May 04, 2013 5:11 am
by rakeshthp
Hi Andrew,

Thanks for your reply. Yes I did use it. But I found the POLYLINE entity wasn't getting read properly.. So I thought I might not be organizing the read information properly. Because, the AcDbPolyline2D type objects were displaying double polylines, as if one polyline is made up of control points and another made up of points generated from these control points. So I came to know that my knowledge of dxf format is not clear and so I started reading the dxf references and I came across these points.

I guess I posted the question in wrong category. Today morning I just saw that there exist category "Creating DXF/DWG itmes". Is it possible to shift this post in that section?

Thanks

Re: DXF format querries..!!!

Posted: Tue May 21, 2013 9:52 am
by rakeshthp
I am not getting the correct result. Does dxflib takes care of OCS to WCS conversion?

Re: DXF format querries..!!!

Posted: Tue May 21, 2013 12:10 pm
by andrew
rakeshthp wrote:I am not getting the correct result. Does dxflib takes care of OCS to WCS conversion?
No. This would have to be handled by the caller at this point.