9.3.1 Constructing a tweak

Commands which change output generally look like

\override Voice.Stem #'thickness = #3.0

To construct this tweak we must determine these bits of information:

• the context: here Voice .
• the layout object: here Stem.
• the layout property: here thickness.
• a sensible value: here 3.0.

Some tweakable options are called “subproperties” and reside inside properties. To tweak those, use commands in the form

\override Stem #'details #'beamed-lengths = #'(4 4 3)

For many properties, regardless of the data type of the property, setting the property to false ( ##f ) will result in turning it off, causing Lilypond to ignore that property entirely. This is particularly useful for turning off grob properties which may otherwise be causing problems.

We demonstrate how to glean this information from the notation manual and the program reference.