8a (!{[0,0.5][0,0.5][0,0.5][0,0.5]}6bc de8d)
// omit zero values:
8a (!{[,0.5][,0.5][,0.5][,0.5]}6bc de8d)
// move all control points by same displacement:
8a (!{0,0.5}6bc de8d)
// change only second segment of broken slur ({} means 0 displacement)
8a (!{}{0,0.5}6bc \break de8d)
Things to consider:
Tweaking ties:
//show control points
1c~? 8c
//tweak:
1c~!{[0,0.5][0,0.5][0,0.5][0,0.5]} 8c
Show control points:
Tweak control points:
Things to consider:
Documentation for modifying slurs:
http://lilypond.org/doc/v2.18/Documentation/notation/modifying-shapes
Show control points code here:
https://github.com/openlilylib/snippets/blob/master/debugging-layout/display-control-points/display-curve-control-points.ly