[geda-user] line end styles?

[Dave McGuire]

Hey folks. Another possibly dumb question here. I am working with
microstrip and CPWG structures in PCB. I currently make trace ends
square by turning traces into elements and then setting their square
flags. That's a bit of a pain. Is there a way to change the end style
of a trace to something other than rounded?

Thanks,
-Dave

[onetmt]

Post by Dave McGuire
Hey folks. Another possibly dumb question here. I am working with
microstrip and CPWG structures in PCB. I currently make trace ends
square by turning traces into elements and then setting their square
flags. That's a bit of a pain. Is there a way to change the end style
of a trace to something other than rounded?
Thanks,
-Dave

I generally use polygons for pcb antennas.

[Dave McGuire]

Post by onetmt

Post by Dave McGuire
Hey folks. Another possibly dumb question here. I am working with
microstrip and CPWG structures in PCB. I currently make trace ends
square by turning traces into elements and then setting their square
flags. That's a bit of a pain. Is there a way to change the end style
of a trace to something other than rounded?

I generally use polygons for pcb antennas.

I had thought about that, but was hoping to avoid that approach, as
these are entire circuits, not just antennas. That'll be a real pain
for that many traces.

-Dave

[DJ Delorie]

Is there a way to change the end style of a trace to something other
than rounded?

PCB does not support alternate trace end cap styles, sorry.

[Dave McGuire]

Post by DJ Delorie

Is there a way to change the end style of a trace to something other
than rounded?

PCB does not support alternate trace end cap styles, sorry.

Ok, I'll work around it. Thanks for letting me know.

-Dave

[Peter Stuge]

Post by DJ Delorie
PCB does not support alternate trace end cap styles, sorry.

Why is this? Obviously it hasn't been implemented, but is that
because internal representation of lines/traces makes it extra
difficult, or rather that noone has had an itch yet?


//Peter

[DJ Delorie]

Post by Peter Stuge
Why is this? Obviously it hasn't been implemented, but is that
because internal representation of lines/traces makes it extra
difficult, or rather that noone has had an itch yet?

Because nobody's implemented it yet (which implies nobody itched
enough to do so ;)

Round end caps are ideal for traces because there's no need to worry
about miter angles.

[Gabriel Paubert]

Post by DJ Delorie

Post by Peter Stuge
Why is this? Obviously it hasn't been implemented, but is that
because internal representation of lines/traces makes it extra
difficult, or rather that noone has had an itch yet?

Because nobody's implemented it yet (which implies nobody itched
enough to do so ;)
Round end caps are ideal for traces because there's no need to worry
about miter angles.

And some exporters would become more complex, for example for non round
ends, the only way to perform Gerber export is basically to transform it
into a contour. Gerber only allows round apertures for circular interpolation.
Rectangular apertures are also allowed for linear interpolation, but only
when the rectangle sides are along the major axes, therefore they only
work satisfactorily for horizontal and vertical traces.

It's not that difficult to add polygons at the end of the traces and it
gives you much more freedom (I've had microstrip lines ending with strange
shapes for wire-bonding).

Speaking of Gerber, we should add a G01* block at the beginning of every
Gerber files produced by the exporter. The specification says that the
interpolation mode (G0[123]) is undefined at the beginning of a file.
I suspect that most Gerber readers assume linear interpolation but this
is not guaranteed.

Gabriel

[Gabriel Paubert]

Post by Dave McGuire
Hey folks. Another possibly dumb question here. I am working with
microstrip and CPWG structures in PCB. I currently make trace ends
square by turning traces into elements and then setting their square
flags. That's a bit of a pain. Is there a way to change the end style
of a trace to something other than rounded?

No. As others, I use solid polygons at the end of the traces.
And sometimes in the middle since I've not found any other way
of doing mitered bends in microstrip and coplanar waveguides.

Gabriel

[Dave McGuire]

Post by Gabriel Paubert

Post by Dave McGuire
Hey folks. Another possibly dumb question here. I am working with
microstrip and CPWG structures in PCB. I currently make trace ends
square by turning traces into elements and then setting their square
flags. That's a bit of a pain. Is there a way to change the end style
of a trace to something other than rounded?

No. As others, I use solid polygons at the end of the traces.
And sometimes in the middle since I've not found any other way
of doing mitered bends in microstrip and coplanar waveguides.

Hey, I hadn't thought of that...that's a damn fine idea. Thanks!

-Dave

[Peter Clifton]

Just out of curiosity, is there a guide or reference available somewhere describing a complete set of the kinds of structures useful for RF work? 

E.g. I didn't know square capped ends were useful until this email thread.

Perhaps a microwave pcb 101 I could read? 


---
Peter Clifton <***@clifton-electronics.co.uk >

(Sent from my phone)

-------- Original message --------
From: Gabriel Paubert <***@iram.es>
Date:01/07/2014 07:13 (GMT+00:00)
To: geda-***@delorie.com
Subject: Re: [geda-user] line end styles?

   Hey folks.  Another possibly dumb question here.  I am working with
microstrip and CPWG structures in PCB.  I currently make trace ends
square by turning traces into elements and then setting their square
flags.  That's a bit of a pain.  Is there a way to change the end style
of a trace to something other than rounded?

No. As others, I use solid polygons at the end of the traces.
And sometimes in the middle since I've not found any other way
of doing mitered bends in microstrip and coplanar waveguides.

Gabriel

[Mark Stanley]

Sent: Wednesday, July 02, 2014 at 6:34 PM
Subject: Re: [geda-user] line end styles?
Just out of curiosity, is there a guide or reference available
somewhere describing a complete set of the kinds of structures
useful for RF work? 
 
E.g. I didn't know square capped ends were useful until this email thread.
 
Perhaps a microwave pcb 101 I could read? 

This might be of assistance to you:

http://microwaves101.com/encyclopedia/mitered_bends.cfm

[Peter Clifton]

From recollection, it is  only supported on "pad" objects, which take a slightly different code path through the renderer / exporters.

Adding a square ended attribute wouldn't be hard for polygon clearance and export purposes, but I expect a lot of the DRC checking and connectivity scanning code will need altering as those are based on round capped geometry.

This said... should only be a matter of subbing in the pad equivalent code.

May inherit the same issue with not being able to determine the orientation of a zero length square capped trace. 


---
Peter Clifton <***@clifton-electronics.co.uk >

(Sent from my phone)

-------- Original message --------
From: Peter Stuge <***@stuge.se>
Date:02/07/2014 10:12 (GMT+00:00)
To: geda-***@delorie.com
Subject: Re: [geda-user] line end styles?

Post by DJ Delorie
PCB does not support alternate trace end cap styles, sorry.

Why is this? Obviously it hasn't been implemented, but is that
because internal representation of lines/traces makes it extra
difficult, or rather that noone has had an itch yet?


//Peter

[Peter Clifton]

Cool, thanks... Not what I was imagining the structure to look like at all.

Why they didn't call it a chamfered bend, I don't know. Perhaps that would just be too consistent with mechanical cad.


---
Peter Clifton <***@clifton-electronics.co.uk >

(Sent from my phone)

-------- Original message --------
From: Mark Stanley <***@technologist.com>
Date:03/07/2014 01:09 (GMT+00:00)
To: geda-***@delorie.com
Subject: Re: [geda-user] line end styles?

Sent: Wednesday, July 02, 2014 at 6:34 PM
Subject: Re: [geda-user] line end styles?
Just out of curiosity, is there a guide or reference available
somewhere describing a complete set of the kinds of structures
useful for RF work? 
 
E.g. I didn't know square capped ends were useful until this email thread.
 
Perhaps a microwave pcb 101 I could read? 

This might be of assistance to you:

http://microwaves101.com/encyclopedia/mitered_bends.cfm