Application extension implementation and Part 21 File for SMCH
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Solid Model Construction History
Abstract Background Scope Model Overview EXPRESS short listing Implementation and Part 21 File
A sample test part was created on a CAD system and illustrates several concepts to be tested initially: sketch, extruded solid, fillet, Boolean operations. The CAD system translator software (pre-processor) for AP 203 generated the Part 21 file for the test part. The file includes the configuration management information, advanced boundary representation structures, geometric validation properties, etc.; of course, it did not contain the extruded solid, fillet, and Boolean operations. Thus, the Part 21 file was hand-edited to include the construction history information.
5.1 Implementation Test Part
The dimensions of the sketch in Figure 3 and the final solid model in Figure 4 are given in inches.
The sketch is the extruded a distance of 8 inches in the +z axis direction to generate an L shaped solid block. The edge forming the concave portion of the solid is filleted using a radius of 2 inches. A hole is created in the horizontal face that the fillet joins. The center of the top of the hole at (7.5, 6.0, 4.0) , the geometric center of the face. A right circular cylinder and a right circular cone are unioned together and then subtracted from the existing solid, to generate a hole with a cylindrical vertical side and a conical bottom. The radius of the top of the hole is 1 inches; the cylindrical part of the hole is height 2 inches and the conical part of the hole is height 1 inch. The semi-angle of the cone is 45 degrees. The final solid model is shown in Figure 4.
5.2 Part 21 File Example
The solid model generated by the AP 203 translator is represented in the Part 21 file as the advanced_brep_shape_representation entity (#11). The translator created all entities through # 400, and the entities beginning with # 410 contain constructs for capturing solid model construction history and were added manually.
The part 21 file SMCH.p21 is on a separate page for electronic readibility.
