Which pcb program allows custom or complex pad design - Page 1
Forum section: electronics / general

author: swmcl
author_rank: Contributor
timestamp: November 04, 2016, 10:33:03 pm
content: Hi,I'm using a package that is more than a decade old. It only allows round or rectangular pads. Is there a package now that would allow me to create pads that are rectangular but with rounded corners?I'm not really thinking of an extended round pad. I'm thinking of a pad that is basically rectangular but has smaller rounds at the corners.While I'm at it, how 'bout some more unusual pad shapes ... I think it was a SOT23 variant the other day that had a centre pad that was a mixture of triangles and rectangular regions. I want to create something like that and then round it all off for EMI purposes in the main. Teardrops I assume would be possible also.Or do they all do it?! The actual pad designing 10 years ago was pretty lame really.I'm looking to upgrade to something mid-range like the Proteus level 3 (top cost). Would prefer to work on Linux if possible. Eagle looks a bit primitive but isn't discounted.Your thoughts appreciated ...Cheers,

author: lorth
author_rank: Contributor
timestamp: November 04, 2016, 10:42:54 pm
content: Eagle, Cadence Orcad, Cadence Allegro and Altium do it.I suposse Kicad as well.

author: jancumps
author_rank: Unknown
timestamp: November 04, 2016, 10:46:42 pm
content: Quote from: lorth on November 04, 2016, 10:42:54 pmYes.

author: swmcl
author_rank: Contributor
timestamp: November 04, 2016, 10:48:34 pm
content: Thanks guys,Is Altium on Linux?It probably costs a bomb ...

author: lorth
author_rank: Contributor
timestamp: November 04, 2016, 11:05:04 pm
content: Nop.... Kicad then

author: rob77
author_rank: Super Contributor
timestamp: November 04, 2016, 11:12:52 pm
content: Eagle also runs on Linux

author: sleemanj
author_rank: Super Contributor
timestamp: November 04, 2016, 11:19:56 pm
content: DipTrace can, it's a bit of a fiddle to draw the pad design directly in DipTrace itself, but you can import a DXF to make it easier.This is how I make offset hole pads, but the shape can be anything (closed, obviously).http://imgur.com/a/eCnD3

author: rob77
author_rank: Super Contributor
timestamp: November 04, 2016, 11:27:25 pm
content: DipTrace has no native Linux version, but runs under wine.

author: timb
author_rank: Super Contributor
timestamp: November 05, 2016, 12:10:18 am
content: Quote from: sleemanj on November 04, 2016, 11:19:56 pmVery nice!Be warned though, sometimes DipTrace goes crazy when exporting polygons with a large number of points (when you convert to pad it pulls it in as a poly). This can cause your fab to have troubles when they try to process the Gerbers.As an example, last week I created 3-way solder jumper. I wanted the outer pads to have rounded edges, so here's how I did it: I created a new pad, set the type to poly and then edited the points. I let it create a 360 point polygon, which was a circle! Then I deleted 180 of the points, leaving me a half circle. Finally, I added a few points to extend the square side.It came out beautifully! Unfortunately, during export, DipTrace turned those ~180 points into *thousands* of operations in the Gerber. OSHPark couldn't process it. So I ended up just using square pads. :-/I think I can fix the problem though... If you ever zoom in on a normal round pad in DipTrace, you can see it's not perfectly round; there's aliasing because they're using a limited number of points to create the circle. So, I suspect if I go back and do the half circle again, but start out with 36 points instead of 360, it'll export just fine.And to the OP: You might also look into a took like PCB Librarian. It'll let you create footprints and custom pads, then export them to pretty much any tool you want.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 05, 2016, 12:13:14 am
content: Just create the shape at the footprint level?And I assure you, custom pads are not some mysterious luxury, SciCards had this decades ago.Of course, you needed a PhD in topology and dark matter to do it, but it was there.

author: swmcl
author_rank: Contributor
timestamp: November 05, 2016, 12:31:18 am
content: Offset pads are excellent ...There is a surprising number of things one would do if they had the CAD drawing features available eh ...I don't need to run on Linux, I'd just prefer to get away from Windows at every opportunity. Most programs are absolute compromises on Linux as there still isn't enough demand for them to be properly implemented (aside from the fact that Linux platform is very moveable because of the politics and lack of central planning...)

author: DerekG
author_rank: Frequent Contributor
timestamp: November 05, 2016, 02:08:13 am
content: Quote from: swmcl on November 04, 2016, 10:33:03 pmIf your existing package allows you to place polygon copper "pours" on the board, you could simply pour the copper shape around the "square" pad & then open up the solder mask to suit. Complete this process for both sides if you need to.You could even make a library component with the above to make it easy.If you package does not allow you to make the library component with the hole for the pad (if through hole), then make the component (ie the copper pour with opened solder mask) with "no hole" & simply place it on top of your existing "square pad".There are many ways to accomplish what you want to do.