Tracing Polyline-connected Components - AutoCAD Electrical

• 

  Coinciding with the acquisition of VIA Development, Nate joined Autodesk in March of 2003 after a decade stint as an entrepreneur following a two-decade stint as a controls engineer and software applications developer at Owens-Corning. Nate is now the lead product architect for AutoCAD Electrical. He loves this stuff.

  About Nate

Latest Post

• Add to Bookmarks Send to Peer

  Tracing Polyline-connected Components - AutoCAD Electrical
  April 11, 2007, 02:58 AM Nate Holt

  This may not be such a great idea... but someone recently asked a question about trying to use AutoCAD Electrical to design PCB's. The answer is "No." It's not set up to do this. Yes, you could do BOM with no problem. But, for component connection and from/to extraction, you'd probably want to use polylines for the traces. AutoCAD Electrical is NOT set up to process point-to-point polyline traces... it is set up to process wire networks consisting of line segments.
  
  But, Just for grins...
  
  Okay, just for fun, let's say you're really desperate. You really want to use AutoCAD Electrical for just a very minimal implementation of this polyline thing. What you can do is use AutoCAD Electrical's "Application Programming Interface" API to create a crude From/To report generator that will process components interconnected with polyline traces.
  
  Normal AutoCAD Electrical Components BUT using Polyline Connections
  
  Here's a simple example. The components are normal AutoCAD Electrical symbols with the TAG1 and RATING1 attributes, terminal attributes, and invisible wire connection attributes, and so on. The traces are POLYLINEs drawn right up to the wire connection point attributes. That's it.
  
  
  
  
  
  From/To Extraction Program
  
  Here are parts of the simple AutoLisp utility that will process this type of drawing and give a rudimentary from/to report (download the whole thing here). The "key" call in this progam is the API function that returns wire connection point data. It is the (c:wd_get_sym_pntlst...) call shown about half-way down in the code snippet below. For each block insert in the drawing, it makes a call to this API function to return the list of data for all of the component's wire connection points. Then it cycles through each point, throws a small "crossing window" around its XY coordinate, and tries to capture a connected polyline. If one or more are found, it saves them in the "p_data" list for processing later.
  
  
  
  Now it has a big "p_data" list of all component connections that appear to tie to a polyline. The final step is to start through this list and find the two end connections on a per polyline basis (i.e. hopefully there are two connections in the list for each polyline found in the drawing). This is done by looking for a match on a common saved "handle" of the polyline entity. For each connection match on a given polyline's handle, the component's tag-ID, terminal pin attribute value, and a few other pieces of data are extracted with a few more API calls.
  
  
  
  Now, with component data found at each end of the polyline trace, the from/to entry is written out to the report in comma-delimited text format (not shown here, see full program). The program loops around until all polylines have been accounted for.
  
  
  Sample Report Output
  
  That's it. It more or less works. Here's the resulting report (called up in Excel):
  
  
  
  1. Download the attached pcb_trace.lsp file
  2. APPLOAD and reference the lsp file
  3. Type PCB_TRACE [Enter] at your command line
  
  
  
  
  

  0 Comment | Add Comment Controlling the Machine > All

Comments