diff --git a/opossum/src/nodes/node_group/mod.rs b/opossum/src/nodes/node_group/mod.rs
index 43d663fe91c292c881757cbbe8c6575ed5608978..167b190e2f8c2cea59476fb005e1adcfcea30d94 100644
--- a/opossum/src/nodes/node_group/mod.rs
+++ b/opossum/src/nodes/node_group/mod.rs
@@ -368,13 +368,13 @@ impl NodeGroup {
     }
     /// Returns the dot-file header of this [`NodeGroup`] graph.
     fn add_dot_header(&self, rankdir: &str) -> String {
-        let mut dot_string = String::from("digraph {\n\tfontsize = 8;\n");
+        let mut dot_string = String::from("digraph {\n\tfontsize = 10;\n");
         dot_string.push_str("\tcompound = true;\n");
         dot_string.push_str(&format!("\trankdir = \"{rankdir}\";\n"));
         dot_string.push_str(&format!("\tlabel=\"{}\"\n", self.node_attr.name()));
         dot_string.push_str("\tfontname=\"Courier-monospace\"\n");
-        dot_string.push_str("\tnode [fontname=\"Courier-monospace\" fontsize = 8]\n");
-        dot_string.push_str("\tedge [fontname=\"Courier-monospace\"]\n\n");
+        dot_string.push_str("\tnode [fontname=\"Courier-monospace\" fontsize = 10]\n");
+        dot_string.push_str("\tedge [fontname=\"Courier-monospace\" fontsize = 10]\n\n");
         dot_string
     }
     /// Export the optic graph, including ports, into the `dot` format to be used in combination with
diff --git a/opossum/src/nodes/node_group/optic_graph.rs b/opossum/src/nodes/node_group/optic_graph.rs
index 9ef535516632cb88589f372cf48228b1ce68a404..79dbc6e64c6c98dce95a4891cc4e83f175c9250f 100644
--- a/opossum/src/nodes/node_group/optic_graph.rs
+++ b/opossum/src/nodes/node_group/optic_graph.rs
@@ -11,7 +11,7 @@ use crate::{
     optic_ref::OpticRef,
     optic_senery_rsc::SceneryResources,
     port_map::PortMap,
-    properties::Proptype,
+    properties::{proptype::format_quantity, Proptype},
     rays::Rays,
 };
 use log::warn;
@@ -34,7 +34,7 @@ use std::{
     collections::BTreeMap,
     rc::Rc,
 };
-use uom::si::f64::Length;
+use uom::si::{f64::Length, length::meter};
 use uuid::Uuid;
 
 /// Data structure representing an optical graph
@@ -681,10 +681,12 @@ impl OpticGraph {
                 .edge_endpoints(edge_idx)
                 .ok_or_else(|| OpossumError::Other("could not get edge_endpoints".into()))?;
 
+            let dist = self.distance_from_predecessor(end_nodes.1, light.target_port())?;
+            
             let src_edge_str = self.create_node_edge_str(end_nodes.0, light.src_port())?;
             let target_edge_str = self.create_node_edge_str(end_nodes.1, light.target_port())?;
 
-            dot_string.push_str(&format!("  {src_edge_str} -> {target_edge_str} \n"));
+            dot_string.push_str(&format!("  {src_edge_str} -> {target_edge_str} [label=\"{}\"]\n", format_quantity(meter, dist)));
         }
         dot_string.push_str("}\n");
         Ok(dot_string)
diff --git a/opossum/src/properties/proptype.rs b/opossum/src/properties/proptype.rs
index 911e742762be7e7ad8613ff150e085c81a9b2a25..deadbe64f37c91f6b790c6d9e582339f5468a403 100644
--- a/opossum/src/properties/proptype.rs
+++ b/opossum/src/properties/proptype.rs
@@ -266,7 +266,7 @@ pub fn format_value_with_prefix(value: f64) -> String {
 
     format!("{:8.3} {prefix}", value / f64::powi(10.0, exponent))
 }
-fn format_quantity<D, U, V, N>(_: N, q: Quantity<D, U, V>) -> String
+pub fn format_quantity<D, U, V, N>(_: N, q: Quantity<D, U, V>) -> String
 where
     D: Dimension + ?Sized,
     U: Units<V> + ?Sized,