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I created a board outline, then wanted to add a polygon pour as a GND plane in the bottom layer of my 2-layer PCB. Altium's design rule checker raises the following error:

Short-Circuit Constraint: Between Board Cutout (Multi-Layer) Region (0 hole(s)) Multi-Layer And Polygon Region (76 hole(s)) Bottom Layer Location : [X = 0mil][Y = 0mil]

Does anyone know a solution to this? There doesn't appear to be any short-circuits within the circuit schematic or routing.

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  • \$\begingroup\$ Then try redrawing the polygon to cover a smaller area and see if you can make it disappear. Fiddle around until the error comes back then, target that area to inspect. \$\endgroup\$
    – Andy aka
    Oct 16, 2021 at 15:03
  • \$\begingroup\$ I tried to polygon pour a small area and it shows the same error. I've targeted the error to be related to the board outline, but am unsure where to proceed from here. \$\endgroup\$
    – Kevin
    Oct 16, 2021 at 15:05
  • \$\begingroup\$ You probably have some constraint value that limits the extent of a flood to the edges of the board (the board cut-out). Try nipping the flood in a mm or so and see what happens. \$\endgroup\$
    – Andy aka
    Oct 16, 2021 at 15:07
  • \$\begingroup\$ It's a short circuit constraint, I'm not sure that this has to do with board constraints \$\endgroup\$
    – Kevin
    Oct 16, 2021 at 15:31

3 Answers 3

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Solution:

Delete board outline, create polygon pour, then create board outline from primitives again. The polygon pour must be the outer outline.

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Your board outline should occupy another mechanical layer on your board. You can do this by opening 'View configuration' tab and create a new mechanical layer as board outline. Then you can draw board outlines using primitives, Design > Board shape > Create primitives from board shape and set layer to 'board shape'

Board shape view configuration

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"Board Cutout (Multi-Layer) Region (0 hole(s)) Multi-Layer"

It looks like you've defined [what you thought was] the board outline, with a cutout region instead.

A board cutout is a Region object, tagged as board cutout and placed on Multi-Layer (the layer is forced when the option is enabled).

The proper way to define board outline is to draw it on a layer (typically Mech 1 or Keep-Out), and D, S, D (Design, Board Shape, Define from Selected Objects). Draw a contiguous non-overlapping path to avoid confusion or errors (a non-contiguous path will usually cause the "create from primitive external edges" dialog, and may not give the result desired).

The board outline is, I think, an object internally, a closed polyline much like a Region, but not selectable as such (or, not normally so). (As of AD14 or so, it used to be editable as such; this was dropped in favor of the redraw mechanism.)

In summary: board outline is positive space, which creates the board area as such. Board cutouts subtract from that outline, creating negative space within the board area. Board cutouts aren't meaningful outside the board boundary (you can't subtract from nothing).

Polygon placement with respect to board outline, doesn't matter; pouring is determined by clearance rules, including to board edge/outline and Keep-Out objects. Normally it's drawn similar to board outline for convenience.

Also check on board planning mode (press 1) to make sure a solid board region of the intended stackup (D, K / Design, Board Stackup) is present.

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