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PLANAR_PATCH

Define a finite-thickness elliptical or rectangular patch in an arbitrary plane. A cell is assigned to the region if the cell intersects the patch (not merely if the cell center lies inside it). See Planar Patch in the Theory Guide.

Required Cards:

PLANAR_PATCH

Opens the PLANAR_PATCH block within a REGION block.

CENTROID <float float float>

Coordinates of the patch center \(\mathbf{c}\).

CENTROID x y z

RADII <float float>

In-plane semi-axes \(a\) and \(b\) (metres). The first radius lies along \(\hat{\mathbf{e}}_1\) (the XY-trace for ANGLES, or the projected AXIS for NORMAL). Both values must be positive.

RADII a b

HALF_THICKNESS <float>

Half-aperture \(h\) (metres) measured along the plane normal. Must be greater than zero. The patch occupies \(|\mathbf{n}\cdot(\mathbf{x}-\mathbf{c})| \le h\).

Exactly one of:

ANGLES <float float>

Trace angles in degrees. The first is the map-view (XY) trace from \(+X\) toward \(+Y\). The second is the XZ-section trace from \(+X\) toward \(+Z\). These angles define the plane of the patch.

ANGLES theta_xy theta_xz

NORMAL <float float float>

Plane normal (normalized internally). Requires AXIS.

NORMAL nx ny nz

AXIS <float float float>

In-plane direction for the first radius. Projected onto the plane (must not be parallel to NORMAL).

AXIS ax ay az

Optional Cards:

SHAPE <string>

ELLIPSE (default) or RECTANGLE.

Examples

REGION fault
  PLANAR_PATCH
    CENTROID 22.75 375. 150.
    ANGLES 45. 45.
    SHAPE ELLIPSE
    RADII 80. 50.
    HALF_THICKNESS 0.5
  /
END

REGION cap
  PLANAR_PATCH
    CENTROID 10.5 10.5 10.5
    NORMAL 0.d0 0.d0 1.d0
    AXIS 1.d0 0.d0 0.d0
    SHAPE ELLIPSE
    RADII 5.d0 3.d0
    HALF_THICKNESS 0.6d0
  /
END

REGION panel
  PLANAR_PATCH
    CENTROID 0. 0. 0.
    NORMAL 1. -1. -1.
    AXIS 0.707106781 0.707106781 0.
    SHAPE RECTANGLE
    RADII 20. 10.
    HALF_THICKNESS 1.
  /
END