Btw - in case the English wasn't clear,=C2=A0 when we sa= y "bloated", we mean an object is grown.

The code might also be bloated.... it isn't the pretties= t corner of pcb's internals.

I'd suggest reading through the existing find.c code and= seeing how you get on understanding that.

2015-12-24 20:16 GMT+01:00 Britton Kerin (britton DOT kerin AT gmail DOT com) [via geda-user AT delorie DOT com] <= span dir=3D"ltr"><geda-user AT delorie DOT com>:

On Thu, Dec 24, 2015 at 4:51 AM, Nicklas Karlsson (nicklas DOT karlsson17 AT gm= ail.com) [via geda-user AT delorie DOT com] <geda-user AT delorie DOT com> wro= te:
There have been some= discussion about DRC clearance calculation. As I understand it now clearan= ce i calculated by growing objects on copper layer and check if netlist cha= nged. Someone suggested calculate distance is better but to know there is n= o copper from other object withing clearance distance is actually good enou= gh. There is however a need for distance then flooding copper within polygo= n areas.

Algorithm clearance:
1. A functio= n to check if there are other copper objects within clearance distance from= a net, currently implemented may be good enough.
1. Assign a net= name to all copper objects/"drawing primitives", probably all dr= awing primitives on copper layer.
1. For each net.
2. F= or each clerance value of this net.
3. For the nets this clearanc= e value should be used.
3. Check if this net are within clearance= distance of nets this clearance value should be used for.

The first question is if current algorithm make drawing primitives= of net which should be checked larger and check if netlist changed is good= enough? I expect lines and arcs would be no problem and I actually also ex= pect text will also work if there is a line width although text is usually<= /div>

I think text (on copper)= is not handled at all in DRC at the moment.
=C2=A0
less important but oute= r corners of square objects? Or outer corners with any angle?

I'm not sure what you mean here.<= /div>
=C2=A0
With this algorithm net different clearance between different nets sh= ould work although it must also be decided how the clearance values should = be attached to the nets. Even though current method to calculate distance m= ay not be perfect it would not stop other parts from being

This is the hardest part.=C2=A0 My under= standing is that at the moment pcb has a few basic types, and a boatload of= flags, only a some of which apply to each type.=C2=A0 There's a lot of= talk about adding attributes but I'm not certain it's a great idea= .=C2=A0 Attributes are a form of duck-typing, and if you've been lucky = enough to spend time with JavaScript you know how that can go. =C2=A0gschem= has all sorts of problems with the wonky, barely-known interpretations of = attribute sets.=C2=A0 Classes and inheritance feel harder up front but you = often end up with a much more maintainable system.
=C2=A0
implemented while= the distance check algorithm may or may not be improved in the mean time.<= /div>

Do anybody have any comments on the algorithm?

If you haven't already = I'd take a look through find.c to get a feeling for how the existing DR= C stuff works.=C2=A0 I think it would work without much change
to= do other clearances.=C2=A0 You probably just need to start at the high-cle= arance part of the net first.=C2=A0 Alternately, a filter could be added to= only throw
a violation if one of the involved parts had a specia= l clearance (I'm a little hazy on the exact order in which DRC finds ne= w connections, but I think the start points happen first).=C2=A0
=
Britton

=C2=A0

Nicklas Karlsson

=