note-collision in Schumann

[philippe hezaine]

Hi
Excuse me. My first post was too big. I've removed the scans.
I'm French and newbie with lilypond. If possible, reply with easy sentences.
I rather prefer lilypond than go game, but sometimes ...
I'm typesetting Berceuse (Schlummerlied op124 n°16) of Schumann. Here is
my ly.file. I've put some measures before the
problem, because I want to show the voices configuration.
I wasn't succesfull with polyphonic model. So,each voice is a "relative
block".

 \version "2.6.4"
%    \renameinput "script-collision.ly"  ( don't work)

     \header {
       instrument = "Extrait de la Berceuse"
     }
        
  melodie  =  {
        \relative c'' {
        \context Voice = "melod" {
       \clef treble
       \key es \major
       \time 6/8
        \phrasingSlurUp
        \partial 8

        s8 % (partial) % because of acciaccatura
        \acciaccatura d8 \stemUp c8\( b! c es d c
        bes4. aes\)
        g\( bes
        aes g\)
        \acciaccatura g8 f\( e! f aes4 d,8 <es bes>4.^(       %~ TieUp
        es8 )\) b'8\rest r8
        \bar "||"
      }
   }
 }


  exceptionun = {
        \relative c' {
        \context Voice = "retouchun" {
        \partial 8

        s8 % (partial)
        s2.*4
        s4. s4 \once \override Stem #'transparent = ##t
        \slurDown bes8(
        \once \override NoteHead #'transparent = ##t
        \once \override Stem #'transparent = ##t
        bes4) s2
        \bar "||"


      }
    }
  }



   unebasse = {
        \relative c {
        \context Voice = "prembass" {
       \clef bass
       \key es \major
       \time 6/8
        \partial 8      
        
        s8 %(partial)
        s2.
        \phrasingSlurUp
        \stemUp
         f8[\( aes16 bes \change Staff=upper \stemDown
        d8]\) f\( \change Staff=lower
        \stemUp
        d16 bes aes8\)
        s2.*2
        s4. s4
        \change Staff=upper \once \override Stem #'transparent = ##t
        \once \override NoteHead #'transparent = ##t
        \slurDown
        aes8(
        \stemDown
        aes4)
        \set followVoice = ##t \once \override Stem #'transparent = ##t
         g8 s4.
        \bar "||"

     }
   }
 }

  deuxbasse = {
        \relative c {
        \context Voice = "deuzbasse" {
       \clef bass
       \key es \major
       \time 6/8
        \partial 8

        s8 % (partial)
	\change Staff=lower \stemDown es8\( aes16 c aes'8\) \change Staff=upper 
\stemDown \phrasingSlurDown c\( aes16 es \change Staff=lower \stemUp c8\)
        \stemDown es,2.
        \phrasingSlurUp
	es8\( bes'16 es \change Staff=upper g8\) \change Staff=lower des,\( g16 
bes \change Staff=upper
        fes'8\)
	\change Staff=lower c,8\( aes'16 c \change Staff=upper es8\) \change 
Staff=lower bes,\( g'16 des' \change Staff=upper e!8\)
% voilà la mesure difficile (le "hic")

        \phrasingSlurDown
     \change Staff=lower aes,,8\( f'16 c' \change Staff=upper f8\) 
\change Staff=lower \stemUp bes,,,8\( bes'16 f' \change Staff=upper
        \stemDown
        <<aes8\) bes>>


        \change Staff=lower \stemUp es,,8\( bes'16 es \change Staff=upper
        \stemDown
        g8\) bes\( g16 \change Staff=lower
        \stemUp
        es bes8\)

        \bar "||"
     }
   }
 }

  exceptiondeux = {
        \relative c {
        \context Voice = "retouchedeux" {

% I can't do it now. It's only for coda which is a variation
%of this problem

      }
    }
  }
     dynamics = {
        s8 % (partial)
         s2.*6
     }

     \score {
       \context PianoStaff <<
   \set PianoStaff.instrument = \markup{ \fontsize #6 {"16. "} \hspace #1.0
}
         \context Staff=upper <<
         \melodie
         \exceptionun
        >>

         \context Dynamics=dynamics \dynamics
         \context Staff=lower <<
           \clef bass
        \unebasse
        \deuxbasse
        \exceptiondeux
         >>

       >>
       \layout {
         \context {
           \type "Engraver_group_engraver"
           \name Dynamics
           \alias Voice % So that \cresc works, for example.
           \consists "Output_property_engraver"

           minimumVerticalExtent = #'(-5 . 5)

           \consists "Script_engraver"
           \consists "Dynamic_engraver"
           \consists "Text_engraver"

           \override TextScript #'font-size = #2
           \override TextScript #'font-shape = #'italic
           \override DynamicText #'extra-offset = #'(0 . 2.5)
           \override Hairpin #'extra-offset = #'(0 . 2.5)

           \consists "Skip_event_swallow_translator"

           \consists "Axis_group_engraver"
         }
         \context {
           \PianoStaff
           \accepts Dynamics
           \override VerticalAlignment #'forced-distance = #5
         }
       }
     }
     \score {
       \context PianoStaff <<
         \context Staff=upper
                \melodie \dynamics
                \exceptionun

         \context Staff=lower <<
        \unebasse \dynamics
        \deuxbasse \dynamics
        \exceptiondeux
        >>

       >>
       \midi {
        \tempo 4=68
         \context {
           \type "Performer_group_performer"
           \name Dynamics
         }
        
         \context {
           \PianoStaff
           \accepts Dynamics
         }
       }
     }
--------------------------------------------------------------------------------------------------------------------------------------------------------
What is the solutions ?  An "horizontal extra-offset"? One another
configuration? When I compile, lilypond says :
AVERTISSEMENT: pas de configuration initiale viable repérée: peut ne pas
repérer une pente de faisceau.
WARNING: Excuse me, I can't translate.

I hope I'm not boring. I've lose one's way
Regards