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Electronics => PCB/EDA/CAD => Altium Designer => Topic started by: slow_rider on June 04, 2026, 09:35:37 pm

Title: My TH vias are not connecting to the power planes in the board.
Post by: slow_rider on June 04, 2026, 09:35:37 pm

I have an 18 layer board, Among the planes I have +5V, -5V & +1.8V. There are TH vias with the same net names that I was hoping to connect to those planes in the stack-up, however no connections are made and the nets are reported unrouted.

I've tried adding a rule to power plane hookup for example: IsVia and InNet('+1.8V') but it does not do anything (testing the query does return the correct results).

Any advise?

Title: Re: My TH vias are not connecting to the power planes in the board.
Post by: thm_w on June 05, 2026, 10:10:00 pm

https://fedevel.com/forum/course-questions/19568-via-s-not-connecting-to-power-planes

https://electronics.stackexchange.com/questions/676556/using-vias-with-power-and-ground-planes-in-altium-designer-20-2-4-cross-error

Screenshot of the via properties, rules, plane settings might help

Title: Re: My TH vias are not connecting to the power planes in the board.
Post by: free_electron on June 05, 2026, 10:18:24 pm

Are they true planes ? and not polygons ?
If they are planes you need to assign the net to the plane or plane section.

This is not a rule problem. it is a net assignment problem

Title: Re: My TH vias are not connecting to the power planes in the board.
Post by: slow_rider on June 05, 2026, 10:58:19 pm

I have included the stack-up.

Layer 7 is a plane with net +1.8V.
Layer 11 is a plane with net +5V.
Layer 12 is a plane with net -5V.

Layers 1, 2, 3, 5, 9, 14, 16, 17, 18 are signal layers with polygon net GND.
Layers 4, 6, 8, 10, 13, 15 are true planes with net GND.

When enabling view of a single plane layer and I can see an X over the via, does that mean it is connected or not (attached screen capture).

I have a rule for power planes and polygons with the first object: IsVia and (InNet('+5V') or InNet('-5V') or InNet('+1.8V'))     

Title: Re: My TH vias are not connecting to the power planes in the board.
Post by: free_electron on June 06, 2026, 04:18:36 am

how is the plane connection defined ? direct connect or relief connect ? toggle it to relief connect and go in single-layer (shift-S) mode on one of the power planes. you should see the wagon-wheel of the thermal spokes around the via.
I believe that cross you see means it is connected. ( i rarely use true planes. i'd have to try it, can't remember)

Altium draws true planes in negative (industry standard)

What is that rule you keep talking about ? the connection mode ? (direct or thermal)

Title: Re: My TH vias are not connecting to the power planes in the board.
Post by: envisionelec on June 07, 2026, 05:22:20 pm

X over the via means a connection is made. Verify this in 3D mode, single layer.