SV3d: DEFINITIONS =BEGINPoint3d: TYPE = ARRAY [1..3] OF REAL;Vector3d: TYPE = ARRAY [1..3] OF REAL;Matrix4by4: TYPE = ARRAY [1..3] OF ARRAY [1..4] OF REAL;Line3d: TYPE = REF Line3dObj;Line3dObj: TYPE = RECORD [base: Point3d,direction: Vector3d,mat: Matrix4by4 -- the z axis of this mat is on line, the origin is base.  mat is orthonormal.];Edge3d: TYPE = REF Edge3dObj;Edge3dObj: TYPE = RECORD [line: Line3d,start, end: Point3d];Poly3d: TYPE = REF Poly3dObj;Poly3dObj: TYPE = RECORD [len: NAT, seq: SEQUENCE maxVerts: NAT OF Point3d];PolyDatabase: TYPE = LIST OF Poly3d;Plane: TYPE = REF PlaneObj;PlaneObj: TYPE = RECORD [A, B, C, D: REAL];Circle3d: TYPE = REF Circle3dObj;Circle3dObj: TYPE = RECORD [origin: Point3d,radius: REAL,plane: Plane];Sphere: TYPE = REF SphereObj;SphereObj: TYPE = RECORD [center: Point3d,radius: REAL,radiusSquared: REAL];END.  ¦  File: SV3d.mesaAuthor: Eric Bier on August 12, 1983 7:27 pmLast edited by: Bier September 24, 1987 12:11:08 pm PDTContents: Definitions for three-dimensional types.base is the closest point on the line to the origin.  direction is the set of direction cosines of the line.  Parametrically, the line is base + t * direction, for all Real t.Plane equation: Ax + By + Cz + D = 0;The normal vector is [A, B, C];The y = 0 plane for instance has A = C = D = 0;If B = 1 THEN normal is [0, 1, 0] pointing up.  Plug in point (4, 5, 6) = 5 (pos, normal side, up).If B = -1 THEN normal is [0, -1, 0] pointing down. Plug in point (4, 5, 6) = -5 (neg, not normal side, up).Ê  ˜ Ihead™J™,J™7J™3JšœÏkœ˜Jšœ˜Jš	œ	œœœœ˜%Jš	œ
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