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Creating New Leaves (Solids/Primitives)

A family of commands exists to allow the user to add more actual solids (leaf nodes) to the model database. To obtain a precise duplicate of an existing solid (presumably to be changed by a subsequent editing command), the copy (cp) command can be used. It is important to note that the copy operation is different from creating an instance of an existing solid; there are occasions to use both operations. If the precise configuration of the solid desired is not important, the make command can be used to create a stock prototype solid of the desired type with the given name, which can then be edited to suit. The mirror command makes a duplicate of an existing solid reflected about one of the coordinate axes.

If the actual numeric parameters of a solid are known, then the in command can be used. In addition to prompting for the descriptions of the full generic primitive solids, this command also accepts abbreviated input formats. For example, a wedge or an RPP can be entered with a minimum of parameters, even though a database ARB8 is created. Similarly, the parameters for a right circular cylinder can be given, resulting in a truncated general cone (TGC) being stored. This is not a very sophisticated way to build solids, but it receives a surprising amount of use.

A number of commands also exist to create new solids with some higher level description. For example, the inside command creates a new solid inside an existing solid, separated from the existing solid by specified tolerances. This is quite useful for creating hollow objects such as fuel tanks. It is possible to create a plate with a specified azimuthal orientation and fallback angle, or to create an ARB8 (plate) by specifying three points and a thickness, or to create an ARB8 given one point, an azimuthal orientation, and a fallback angle.



Next: Specific Cases Up: CREATING NEW OBJECTS Previous: CREATING NEW OBJECTS



Wed Feb 16 13:46:53 EST 1994