After you have started the chaining procedure by selecting the first element in the chain, you might encounter a branch point—that is, the ends of more than two elements might meet at the same place. This location is called a branch point because the chaining can branch to any one of these elements at this point. If this should occur, SURFCAM requires that you indicate which of the eligible elements to use as the next element.
In the drawing there are two curves, each made of arcs and lines. These curves intersect at a point that is the end point of four line segments.
If a chain is needed from the top end of the top curve down to its end on the left side of the drawing, that top end is selected as the beginning element. SURFCAM then searches down the elements one by one until it comes to the junction.
Since there are three different directions to continue the chaining, SURFCAM will place a small box at the junction, and will prompt you to select the next element or End to finish. At this point, you would select the line to chain next. This example uses the line toward the bottom left.
When this is done, SURFCAM will automatically chain the remaining elements since there are no more branch points. If you had chosen End, the chain would stop at the branch point.
When you are prompted to "Select beginning element," proceed as follows to describe the chain:
Select the beginning of the first element in the chain with the mouse. The word Close will appear on the menu, and you are prompted to select the ending element.
If there
are no more elements to chain, click Close.
Otherwise select the trailing end of the last element to be chained. The
elements are sequentially selected, the colors of the elements will change,
until a branch point or the end of the chain is reached.
If the end of the chain is reached, the chain is finished, otherwise
SURFCAM will place a small box at the branch point and will prompt you
to select next or end.
Select the element neighboring the branch point for the next element in the chain. SURFCAM responds as in the step above.
Repeat step 3 for each branch point encountered.