Function trim_up_to_next 

pub fn trim_up_to_next(
    model: &mut NamedModel,
    namer: &Namer,
    sheet: ShellId,
    targets: &[SolidId],
    (start, end): (&HashSet<String>, &HashSet<String>),
    params: RemeshParams,
) -> GeopResult<ShellId>

Trims the sheet sheet up to the next face of any of targets: keeps the piece of it that its edges named start lie on — up to where it meets their boundary — and drops the rest. targets are not changed.

What the trimming creates is named by namer as a boolean names what it creates (see naming). Fails if the piece also reaches an edge named in end: nothing stopped the sheet.