A fragment (sometimes called surface fragment) is a collection of Legs. Fragments have either a left or right orientation and can not cross the template attachment (usually CL) point or overturn on themselves.
The direction of a fragment is always from the template attachment point outwards.
The following table explains the Fragment properties.
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1. Side
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The side property indicates the side of the fragment with respect to the template attachment point. It can be either Left or Right. |
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2. Reference Surface |
The reference surface is used for testing occurrence and for closing operations (see Leg properties). The property can be an explicitly set reference surface or a surface variable. |
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3. Flags |
Display - display on or off Include in Volumes – if set the fragment cut/fill volumes will be calculated. Note fragment volumes are calculated between the fragment and the current merged surface (see Fragment Volumes). Include in Merged Surface - if set the fragment will be added to the merged surface. Material - specifies the material category for volume calculations. Exclusion - similar to legs, the fragment can be excluded if it ends above or below the reference surface. |
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4. Tie Points |
The fragment must have at least 1 tie point and can optionally have 2. If a 2nd tie point is specified the fragment will be stretched either horizontally, vertically or both. Tie Point Type The tie point can be any on of the following: Centerline – The centerline or template attachment point. Outside – The outer most point (furthest from CL) among the set of already processed fragments. Template point code – A coded point. Note the point must have already been processed. If the tie point doesn’t exist the fragment will be skipped. Component attachment point – The fragment is attached to the parent components attachment point. End of last surface fragment (successfully processed) - The fragment is attached to the end of the last fragment (or C/L if the first fragment). Note the fragment is always created. Start of last surface fragment (successfully processed) - The fragment is attached to the start of the last fragment (or C/L if the first fragment) . Note the fragment is always created. First Fragment in the component. - The fragment is attached to the first fragment in the component. End of previous fragment (if it exists). The fragment is attached to the end of the previous fragment only if it exists. This differs from “End of the last surface fragment” in that; if the previous fragment doesn’t exist this fragment will be skipped also. Start of previous fragment (if it exsts). The fragment is attached to the start of the previous fragment only if it exists. This differs from “Start of the last surface fragment” in that; if the previous fragment doesn’t exist this fragment will be skipped also. Tie Point Offsets Vertical and horizontal offsets can be specified for a tie point. These offsets can also be parameters. Fragment Stretching Using a Second Tie Point If a second tie point is specified, the fragment is stretched (adjusted) horizontally, vertically or both. Legs in the fragment can be flagged to be included or excluded from the adjustment (see Leg flag Adjust if parent surface has multiple ties ). In the stretch is horizontal or vertical only, the slopes of the legs are preserved and the length is adjusted |
For more information see Custom Template Components.