Dave, Yu-Ming Luo,
        just to join the consensus here. I do exactly the same procedure
that Dave has explained. It would be a great boost to Protel if they would
implement a paired mechanical layers scheme. As boards get more dense and 2
sided assemblies the norm, there is presently too much work manually
fidgeting with these unruly procedures to do what other packages do
intuitively and automatically.
        I also would back a change in the designator string to something
like ".desg", ".des2" or just ".des", that would be a very simple change for
someone to implement at the source code level. The full ".designator" string
is just too damn long on small components, needlessly extending the
component boundaries far beyond what is practical.
        I previously used Accel EDA at my former employer, Accel had this
stuff very right. I could make 'any' custom attribute, schematic or PCB,
have any number of attributes and stuff those attributes from a database or
permanently store them in the part during library creation. For the custom
attributes you could make as many of them as you could practically use. One
could put the whole datasheet specs into custom schematic attributes if you
were so inclined. They did have a limit of one layer pair on the layer
swapping to match the component layer but it was all that I needed.

Brad Velander,
Lead PCB Designer,
Norsat International Inc.,
#300 - 4401 Still Creek Dr.,
Burnaby, B.C., V5C 6G9.
Tel. (604) 292-9089 direct
Fax (604) 292-9010
website www.norsat.com


> -----Original Message-----
> From: Dave Eloranta [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, August 21, 2001 6:47 AM
> To: 'Protel EDA Forum'
> Subject: Re: [PEDA] Customize layer pairs
> 
> 
> Yu-Ming Luo
> You have identified a long time problem with Protel. I have my library
> components constructed with a .designator string and an 
> outline much as you
> describe. Mine are on Mechanical 1, from days with only 4 
> mechanical layers.
> My outlines are 4mil lines centered ten mils beyond the max 
> part dimension
> or max pad extension whichever is greater. When I place 
> components and see a
> mil between outlines I'm confident that a pick and place 
> machine can get to
> it with a 25mil component to component spacing. When I have 
> components on
> both sides, I unlock components on one layer only and 
> globally change the
> .designator string to another layer for the 2nd page of the assembly
> drawing. I still need to reposition the strings manually. 
> Most importantly
> relock all primitives. One of the difficulties is the length of the
> .designator string. It should have an abbreviated form (4 
> chars would be the
> same length as R999 for example) so that it does not extend beyond the
> component so far. On a crowded area surrounding an OP AMP for 
> example a
> mouse click will select every component in the area depending on the
> orientation of the parts and the size of the .designator string. The
> .designator string also causes parts to autoplace farther 
> apart than I would
> normally place them. My recommendation is to have a process to center
> .designator strings on component pads centroid. This should be done by
> component layer and have orientation options  for specifing that
> .designators can be allowed freedoms. Check boxes would allow 
> no rotation
> changes if the 0, 90, 180, 270 were all checked.
> I have too many last things to do on every circuit board and 
> of course the
> truth is only one thing can be last and one priority can be 
> highest. I think
> this is an example of a low priority at Protel.
> Dave E
> 
> 

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