Disable routing to a pad? - Page 1
Forum section: electronics / general

author: microbug
author_rank: Frequent Contributor
timestamp: April 09, 2025, 09:25:49 am
content: Hi all,This has been driving me up the wall recently. I'm routing a board that has a large electrical through hole pad on the top layer (a surface mount threaded pillar). On the bottom layer it's just a mechanical hole. However, every time I try to start routing from the circled pads that fall under the top layer copper for this pad, Altium starts routing from the centre of the bottom layer mechanical hole rather than the ESD diode pads circled (or if I use differential routing, I just get an error about no complementary net existing).Is there a solution here that I'm missing? So far I've been manually moving the pad out of the way every time I need to route under it...Edit: starting the routing from the other pads that aren't under the pillar also works, but this doesn't work everywhere because some nets are completely under a pillar.

author: ajb
author_rank: Super Contributor
timestamp: April 09, 2025, 04:30:00 pm
content: Have you tried removing the bottom layer pad from the pillar Pad Stack (setting the size to zero)? Or maybe create the footprint with the non-plated hole and top side pad as separate objects?

author: thm_w
author_rank: Super Contributor
timestamp: April 09, 2025, 08:26:04 pm
content: Is hotspot snap set to off (Shift+E)?

author: tooki
author_rank: Super Contributor
timestamp: April 09, 2025, 08:40:31 pm
content: Try using single-layer mode (shift+S, I think) and/or setting snapping to the current layer only (and make sure you’re starting with the bottom layer active!).You can also try reducing the hotspot snap distance.

author: microbug
author_rank: Frequent Contributor
timestamp: April 10, 2025, 08:03:49 am
content: None of those suggestions work unfortunately. Even with snapping turned off entirely / single layer mode / zero size bottom layer hole, it still snaps to the centre of the hole when clicking anywhere within the diameter of the top layer pad.

author: tooki
author_rank: Super Contributor
timestamp: April 10, 2025, 09:01:43 am
content: Ok, I tried it and can reproduce the issue. It’s not an issue of where the snap point is, but that it’s picking up the wrong net. For some reason, it’s prioritizing the through-hole’s net, even if it correctly snapped to the SMD pad. I can’t find any workaround, either.

author: Pseudobyte
author_rank: Frequent Contributor
timestamp: April 10, 2025, 10:44:44 pm
content: Quote from: ajb on April 09, 2025, 04:30:00 pmThis is the only work around. Just tried this and it works.

author: wraper
author_rank: Unknown
timestamp: April 10, 2025, 10:49:32 pm
content: Quote from: microbug on April 09, 2025, 09:25:49 amThose USB capacitors are begging to crack due to mechanical stress if placed like this.

author: tooki
author_rank: Super Contributor
timestamp: April 11, 2025, 11:22:15 am
content: Quote from: Pseudobyte on April 10, 2025, 10:44:44 pmActually, a potentially better way (if it works!) might be to make a custom footprint where the pad itself has a very minimal ring, and then has a circular copper region added for the threaded insert. That would allow the hole to be plated.

author: hwasti
author_rank: Contributor
timestamp: June 02, 2025, 12:09:33 pm
content: Quote from: Pseudobyte on April 10, 2025, 10:44:44 pmThat is almost the right answer.You need a non-plated hole, with a separate copper circle around it on the top side so you can solder your "pillar" to it. That will work in Altium, but it will not work in real life. Even the slightest side-load on the "pillar" in manufacturing, shipment, handling or assembly, and the pad will peel right off the board.That pad needs several vias on it to make sure it cannot peel off.If you need to ground this "pillar", you can assign the copper circle on top to ground and the vias will provide the connection.I have a footprint with the non-plated hole and a pad on the top layer. This footprint is associated with a component in the schematic that connects the pad to ground.But you can do it with free primitives as well.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 03, 2025, 11:20:22 am
content: As a workaround:1. Move the big round thing away.2. Draw the track.3. Move the big round thing back to where it was.I am a KiCad user myself, don't have altium, but I guess this should work for you.

author: microbug
author_rank: Frequent Contributor
timestamp: June 03, 2025, 02:19:11 pm
content: Yes, this was my approach rather than changing the footprint. Accompanied by some grumbling at Altium.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 03, 2025, 02:27:28 pm
content: You can always try out KiCad for free.Maybe it avoids some of the grumbling and makes you more enthusiastic about electronicsIf you like KiCad, you can go on keeping using it for free, no cloud stuff or license anxiety.Also, Both KiCad and altium have importers for each other's projects. The KiCad one works quite good. I don't know how good the altium version works.

author: microbug
author_rank: Frequent Contributor
timestamp: June 03, 2025, 02:49:00 pm
content: I do really like KiCad and have used it many times. Sadly Altium is still far ahead of it for such a complex project (7GHz RF, heterogeneous stackup, complex DRC requirements, tight mechanical tolerances requiring a more advanced 3D viewer/editor).

author: tooki
author_rank: Super Contributor
timestamp: June 03, 2025, 06:04:41 pm
content: Quote from: Doctorandus_P on June 03, 2025, 02:27:28 pmYou can use KiCad to successfully make almost any PCB. But you have to do a lot more by hand. KiCad is getting better (and I almost think it’s accelerating), but Altium is still way ahead in a lot of things. And not just in advanced features. KiCad lacks (or in some cases, lacked until recently) a lot of banal functionality.I mean, the bug that is the subject of this thread is in exactly one of those things: snap behavior. In Altium it’s highly configurable, and that makes it extremely useful. In KiCad it’s quite basic.