diff --git a/src/db/db/dbBoxScanner.h b/src/db/db/dbBoxScanner.h
index fe7cbbff0..6a59239dc 100644
--- a/src/db/db/dbBoxScanner.h
+++ b/src/db/db/dbBoxScanner.h
@@ -297,10 +297,10 @@ public:
    *  @brief Get the interactions between the stored objects
    *
    *  Two objects interact if the boxes of the objects enlarged by the given value overlap.
-   *  The enlargement is specified in units of width and height, i.e. half of the enlargement
-   *  is applied to one side before the overlap check.
    *
-   *  An enlargement of 1 means that boxes have to touch only in order to get an interaction.
+   *  An enlargement of 1 means that boxes have to touch in order to get an interaction.
+   *  An enlargement of 0 means that boxes have to overlap in order to get an interaction.
+   *  To capture interactions between object precisely spaced d, use d+1 for the enlargement.
    *
    *  The box scanner will report all interactions to the receiver object. See box_scanner_receiver
    *  for details about the methods that this object must provide. 
diff --git a/src/db/db/dbLocalOperation.h b/src/db/db/dbLocalOperation.h
index 8f8651865..28ef522c9 100644
--- a/src/db/db/dbLocalOperation.h
+++ b/src/db/db/dbLocalOperation.h
@@ -114,7 +114,8 @@ public:
 
   /**
    *  @brief Gets the interaction distance
-   *  A distance of means the shapes must overlap in order to interact.
+   *  A distance of zero means the shapes must overlap in order to interact.
+   *  A distance of 1 means the shapes need to touch in order to interact.
    */
   virtual db::Coord dist () const { return 0; }