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Start with the physical or electrical requirement

Describe the requirement in ordinary engineering terms before drawing the boundary. A connector may need component access, an antenna may need a defined copper-free region, and a mounting feature may need physical space. Those requirements are not equivalent. Translate each into the relevant layout constraints and manufacturing notes instead of using one oversized polygon for all purposes.

Record the source of the requirement: a component reference design, mechanical envelope, system isolation rule or reviewed manufacturing constraint. Include the controlling dimension and tolerance where applicable. An attractive shaded region has little value if nobody knows why it exists or whether a later revision may change it.

Avoid copying a distance from an unrelated tutorial as a universal rule. Voltage, environment, material, construction and applicable standards can affect a real separation requirement. A keepout is a way of representing part of that requirement in CAD; its presence does not establish that the requirement itself is adequate.

A drawn boundary is not a complete instruction

Select the object classes that must be restricted

Altium documents object-specific restrictions for vias, tracks, copper, SMD pads and through-hole pads. Review the selected classes explicitly. An object type that is not restricted may be allowed in the region; a via-only restriction is therefore different from a broad copper exclusion. The exact behavior should be checked with representative objects in the installed version.

For example, a region intended to prevent vias near a mechanical operation may still allow a surface trace if the engineering requirement permits it. A region intended to exclude poured copper may require a different configuration from one intended to block routing. Describe that distinction in the design record so another engineer does not broaden or narrow the constraint accidentally.

Do not treat a polygon-pour cutout and a general keepout as interchangeable merely because both can produce an empty-looking area. Choose the object that expresses the intended operation, then inspect the final copper after regeneration. The official keepout documentation discusses the difference; your release still needs a visible outcome check.

Altium Keepout Layer review

Set the layer scope deliberately

A restriction applied on a particular signal layer and one defined for all layers can produce different results. Confirm where the object lives and what the software interprets that layer assignment to mean. A bottom-side issue is not resolved by a top-layer restriction simply because the two overlap in a combined view.

Inspect multilayer cases in a way that makes the affected copper layers visible separately. Copper planes and signal-layer objects do not necessarily share the same editing semantics. Avoid extrapolating a two-layer demonstration to every plane or stack configuration. The worksheet asks for scope information so an unresolved layer question remains visible.

Use a small test object in a copy of the design when investigating behavior. Try a representative track, via or pad on the intended layer and examine both editing behavior and the relevant rule result. Remove the test object before release. A screenshot of an empty region does not establish which object classes the constraint actually checks.

Keep the board shape, courtyard and machining distinct

The board shape describes the physical board boundary in the native design. A courtyard describes component placement space. A keepout constrains selected layout objects. A fabrication outline or routing instruction communicates physical manufacture. These may have related geometry, but their meanings and export paths differ.

If a slot is needed, define the appropriate physical feature and provide the agreed manufacturing information. A keepout around that location can support clearance planning, but it does not instruct a fabricator to remove substrate. Likewise, a mounting screw envelope may need both mechanical clearance and electrical restrictions; one editor object may not describe the full requirement.

The mechanical-layer guide explains how to label drafting and manufacturing roles. Do not put a dimension line into the same undifferentiated output as the finished contour and expect the recipient to infer the intended operation. A clear drawing separates what must be made from what merely helps a human read the design.

Inspect regenerated copper and exported data

After editing a restriction, regenerate relevant design-dependent objects and examine the resulting copper. Review narrow slivers, unexpected return-path interruptions and clearances near pads or vias. A local geometry fix can affect a signal return or power path elsewhere in the design, so the review should consider the circuit function as well as the highlighted area.

A keepout may influence the native design without appearing as a corresponding object in manufacturing output. Altium documents export limitations for layer-specific keepouts. The receiving file review should therefore examine the resulting copper and physical instructions, not assume that a factory receives the same constraint objects shown in the editor.

For a worked review, imagine an antenna exclusion area required on several layers. The top view looks clear, but an inner copper layer was not included in the intended restriction. A layer-by-layer output inspection exposes the discrepancy. The correct remedy depends on the antenna design requirement, not a rule that every antenna must use the same all-layer clearance.

Record the reason and the next engineering action

The worksheet produces a self-reported review brief from the selected scope and entered requirement. Treat its result as a list of issues to confirm. It does not infer a safe voltage spacing, approve a component envelope or certify DRC completion. Keep the relevant drawing or source requirement with the brief when asking another engineer to review the area.

For manufacturing discussion, provide the affected layer or feature, the required finished result and a marked drawing with units. Distinguish a firm requirement from a proposed layout approach. This makes it possible to discuss alternative constructions or fabrication details without accidentally changing the circuit requirement.

Use mm-to-mil conversion when the controlling dimension needs a second unit, and the release checklist before handing off files. This page is based on official documentation and a local worksheet; native Altium editing and rule behavior were not exercised here. Verify the actual design in the licensed application used for the project.

Retain the meaning behind the drawing

Attach dimensions to identifiable physical features and state the controlling unit. A scale factor, layer number or shaded area is incomplete without its purpose. Keep physical geometry, annotations and editor constraints distinguishable so another engineer can decide which information governs manufacture and which supports design review.

When a transformation or layer mapping changes, inspect a representative feature before applying it broadly. Compare both global dimensions and local relationships, including side convention and origin. Retain the source, settings and observed result. The worksheet can organize arithmetic or a declared review state, but the native design and receiving output must still be examined. Do not turn a consistent-looking drawing into a production approval without resolving the actual feature requirements.