Finetuning of ground clearance, resolves #467

Signed-off-by: Philipp Rosenberger <philipp.rosenberger@epro-systems.de>

Author: PhRosenberger

osi_object.proto

@@ -292,6 +292,7 @@ message MovingObject
     // The base parameters of the vehicle.
     //
     // \note The bounding box does NOT include side mirrors for vehicles.
+    // \note The height includes the ground_clearance, so always goes from top to ground.
     //
     optional BaseMoving base = 2;
 
@@ -442,11 +443,12 @@ message MovingObject
         //
         optional Vector3d bbcenter_to_front = 5;
 
-        // Static minimal distance in m of under-body plane to ground
-        // surface plane (i.e. disregarding driving dynamic effects or road
-        // surface effects) under neutral load conditions. Can be useful to
-        // approximate the clear area under a vehicle that a sensor can see
-        // through.
+        // Static minimal distance or space from the lowest point of the vehicle,
+        // under neutral load conditions (i.e. disregarding driving dynamic
+        // effects or road surface effects), to the surface plane below it.
+        // Can be useful to approximate the clearance area under a vehicle
+        // that a sensor can see through.
+        // \note \c ground_clearance is included in the bounding box height.
         //
         optional double ground_clearance = 6;