     text: tr "~NODE-RELATION-EDIT.SUBTRACTED_FROM"
     postfixIco: "subtracted-from"
     formula: "-in"
-    magnitude: 0
+    magnitude: -1 # triggers '-' relationship symbol
     gradual: 0
     func: (scope) ->
       return -scope.in

    if vector && scalar
      magnitude = vector.magnitude * scalar.magnitude
      gradual = scalar.gradual
    {vector, scalar, accumulator, transferModifier, magnitude, gradual}

  @thicknessFromRelation: (relation) ->

    text: tr "~NODE-RELATION-EDIT.ADDED_TO"
    postfixIco: "added-to"
    formula: "+in"  # needs to be +in to differentiate from @transferred
    magnitude: 1  # triggers '+' relationship symbol
    gradual: 0
    func: (scope) ->
      return scope.in
