obj_query

    SCHEMATIC objects use the dotted spelling:
    "Text,Location.X,Location.Y" for net labels
    "Designator,Name,ConnectionX,ConnectionY" for pins.
    ConnectionX/ConnectionY are the pin's ELECTRICAL end --
    the point a wire or net label must sit on to attach.
    Location is the BODY-side root and is NOT the connection
    point; deriving the end by hand from Orientation and
    PinLength is a common source of wrong conclusions about
    what is wired.
    "Designator.Text,Comment.Text,LibReference" for components
    A managed (Workspace) component also reads, but does not
    write, "LibIdentifierKind,LibraryIdentifier,DesignItemId,
    VaultGUID,ItemGUID,RevisionGUID,SymbolReference,
    SymbolVaultGUID,SymbolItemGUID,SymbolRevisionGUID". Read
    off a part Altium placed, they are the values the managed
    tools need.

    PCB PRIMITIVES DO NOT. They are a separate, flat set,
    and mixing the two is the single commonest mistake here:
    a caller who used Designator.Text infers a dotted rule,
    writes Net.Name on a track, and gets an error naming the
    right spelling. Net is the one that catches people, and
    it is plain "Net":
    "Net,Layer,Width" for tracks
    "Net,Layer,HoleSize,Size" for vias
    "Designator,Comment,Pattern,Rotation,X,Y" for components
    "Text,Height,StrokeWidth,IsDesignator" for texts
    Full set: ObjectId, X, Y, Layer, Descriptor, Selected,
    Net, X1, Y1, X2, Y2, Width, Radius, StartAngle,
    EndAngle, XCenter, YCenter, HoleSize, Size, TopShape,
    TopXSize, TopYSize, Rotation, Name, Text, Pattern,
    Designator, Comment, SourceDesignator, Kind,
    RemoveDead, RemoveNarrowNecks, RemoveIslandsByArea,
    StandoffHeight, OverallHeight, BodyOpacity3D, InComponent, Component,
    InPolygon, IsKeepout, Locked, Layer1, Layer2,
    IsRedundant, Mode, Height, StrokeWidth, IsDesignator,
    IsComment, UseTTFonts.

    On a text, Height and StrokeWidth are writable in mils
    (Altium's own names, Size and Width, answer the same).
    On a via, Size and HoleSize are writable; a write that
    would leave the hole as large as the pad is refused, so
    give Size first to grow a via and HoleSize first to
    shrink it. Lengths read back in decimal mils.
    On a pad, Name and Designator both read and write its
    designator; an empty one is refused.
    On a 3D body, BodyOpacity3D reads and
    writes 0 (clear) to 1 (solid), not a percentage.
    IsDesignator and IsComment pick out component labels:
    filter "IsDesignator=true" for every designator.

    A board type walks EVERY primitive of that type, a
    footprint's own tracks and a hatched polygon's tracks
    with the routing, on the same copper layers. Filter
    "InComponent=false|InPolygon=false" keeps to free copper;
    Component is the owning footprint's designator.

    An unrecognised PCB property is REFUSED and the reply
    lists the valid ones. It used to come back empty, which
    is indistinguishable from a property that is genuinely
    blank, and that ambiguity has three times been read as
    "the bridge cannot see this data".

    A track on a mechanical layer really does have no net,
    so filter to copper before concluding anything from an
    empty Net: filter="Layer=TopLayer".
scope: Document scope:
    "active_doc", current sheet only (default)
    "project", all SCH sheets in focused project
    "doc:C:\path\to\Sheet.SchDoc", specific sheet by path (no focus change)
    "project:C:\path\to\Project.PrjPcb", specific project by path
    "lib_component:NAME", a named symbol in the active SchLib
    "lib_component:NAME@3", part 3 of a MULTI-PART symbol.
        A SchLib iterator yields one part at a time, so
        without the suffix only part 1 is visible and a pin
        on part 3 reports matched:0. Query each part in
        turn to cover the whole component. The suffix is
        read from the RIGHT, so a LibRef containing '@'
        still works.
        Ask for the `OwnerPartId` property to see which
        part a returned primitive belongs to (0 means
        shared across every part).
filter: Pipe-separated property=value conditions (AND logic), e.g.:
    "Text=VCC", match net labels with Text equal to VCC
    "Designator.Text=R1", match component with designator R1
    "" (empty), match all objects of the type
    On a PCB type a length (X, Y, X1, Y1, X2, Y2, Width, Size,
    HoleSize, ...) matches as a number in mils, to 0.00005
    mil, with '.' or ',' as the decimal point:
    "X2=3172.6356" and "X2=3172,63560" are the same filter.
limit: Maximum number of objects to return (0 = unlimited)