Melting KiCad – making curved traces

KiCad has improved a lot, but one of the features it’s really lacking is the ability to do smooth, rounded traces with teardrops (fillets on pads and vias).

A lot of early, hand drawn PCBs had this look, where every connection is smooth and slightly melted.

When people first switched to using computers to design circuit boards, the routing options were very limited and traces were forced to have sharp corners. Some people forget that our tendency to restrict traces to 45° angles is mainly a holdover from before there were any other options.

Some of the benefits of teardrops and smooth traces are controversial, but the following can generally be agreed upon:

  • Smooth corners are potentially less prone to errors in the etching process
  • In the case of drill/pad misalignment, teardrops reduce the chance of a breakout
  • For flexible PCBs, sharp corners are stress concentrators, so removing them reduces the chance of cracking
  • Denser routing is possible when arbitrary angles are permitted
  • There may be some electromagnetic compliance (EMC) benefits, since sharp transitions represent a sudden change in impedance

Curved traces are apparently on the roadmap for KiCad 6, which hopefully isn’t too far in the future, but I’m not holding my breath.

Another way to add functionality is via “action plugins” – Python scripts. This is in many ways more limited, but has the massive benefit of not needing to recompile the KiCad source code.

See the details in the post here.

The improvements to the teardrop plugin have been submitted and merged into Niluje’s kicad_scripts repo. The plugin can be found here.

Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here:

Join Adafruit on Mastodon

Adafruit is on Mastodon, join in!

Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Join over 36,000+ makers on Adafruit’s Discord channels and be part of the community!

CircuitPython – The easiest way to program microcontrollers –

Maker Business — “Packaging” chips in the US

Wearables — Enclosures help fight body humidity in costumes

Electronics — Transformers: More than meets the eye!

Python for Microcontrollers — Python on Microcontrollers Newsletter: Silicon Labs introduces CircuitPython support, and more! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi

Adafruit IoT Monthly — Guardian Robot, Weather-wise Umbrella Stand, and more!

Microsoft MakeCode — MakeCode Thank You!

EYE on NPI — Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey

New Products – Adafruit Industries – Makers, hackers, artists, designers and engineers! — #NewProds 7/19/23 Feat. Adafruit Matrix Portal S3 CircuitPython Powered Internet Display!

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at !

No Comments

No comments yet.

Sorry, the comment form is closed at this time.