Merges two adjacent short cubics into a single cubic where the variable smallc in the file variables.xsl is the maximum length of the two curves. This is initially set to 40 but can be changed by the user.
The diagram below shows the curves resulting from multiple uses of merge.
Figure 13.2: Break Cubic
The algorithm used is to find the centre points of the two short cubics and then construct a new cubic that goes through the two end points and the two centre points. Checks are made to see if the new cubic is a good fit. The changes are not made if the fit is poor.