CHAPTER 14

PARAMETRIC INTERSECTION OF SURFACES

An additional facility to compute the parametric intersection of one or more sculptured surfaces with a plane or other scupltured surfaces has been provided. INTSEC produces intersection data between surfaces which can be written onto the EXFILE or punched as APT source code. In the following intersection formats the plane surfaces and the first set of sculptured surfaces are the drive surface (DS) and the second set of surfaces is the part surface (PS) in the APT convention. PS and DS thicknesses and tolerances can be applied to the surfaces with APT THICK/, TOLER/, OUTTOL/ and INTOL/ statements. In all cases the thickness is used in the sense of the surface normals. Non_native geometry can be used if the appropriate evaluator is available.

14.1 The Intersection Between a Plane and surfaces

The following statement allows the intersection between a plane and sculptured (including non-native) surfaces. line 40 INTSEC/ ›,WITH! ›,ssurf ! ›,CANON! plane 1 o Between 1 and 40 sculptured surfaces can be intersected with a given plane surface (duplicate surfaces are eliminated from the list). o The intersection result of multipatch surfaces is ordered to a closed contour before output. o Internal multipatch boundaries can be noticed by double points in the output. o The extended EXFILE data definition is serviced (see section 12.5): The data types TP, TA, TV, PDS, NDS, PPS, NPS, UVPPS are available. o If CANON is coded, APT-source-coded point definitions are punched on FORTRAN file 7 in the following format: PTxxxx(i) = POINT/a,b,c where xxxx is an internal patch ordering number. The name and index of the surface involved is punched in columns 73 to 80 of the records.

14.2 The Intersection Between Surfaces

The following statement allows the intersection between sculptured (including non-native) surfaces. 20 20 INTSEC/ ›ssurf1,! WITH ›,ssurf2! ›,CANON! 1 1 o Up to 20 sculptured surfaces as drive surfaces can be intersected by up to 20 other sculptured surfaces as part surfaces (duplicate surfaces are eliminated from both lists, self intersection is not allowed). o The intersection results of multipatch surfaces is ordered to a closed contour before outout. o Internal multipatch boundaries can be noticed by double points in the output. o The extended EXFILE data definition is serviced (see Section 12.5): The data types TP, TA, TV, PDS, NDS, UVPDS, PPS, NPS, UVPPS are available. o If CANON is coded, APT-source-coded point definitions are punched on FORTRAN file 7 in the following format: PTxxxx(i) = POINT/a,b,c where xxxx is an internal patch ordering number. The name and index of the surface involved is punched in columns 73 to 80 of the records.