diff --git a/src/docs/part1/simple_detector.md b/src/docs/part1/simple_detector.md
index d8127ff0aa50ad4ebc4d8de990087fd2bde2aac6..d8ed2a85f0ee676f8fa912fe9fac1de43c25188c 100644
--- a/src/docs/part1/simple_detector.md
+++ b/src/docs/part1/simple_detector.md
@@ -100,9 +100,17 @@ This
 
 Later on you can see its use:
 ```cpp
-      auto pos1 = cellid_converter.position(h.cellID);
+  auto pos1 = cellid_converter.position(h.cellID);
 ```
 
+### Cell size
+
+You will see this:
+```bash
+...
+Segmentation-Cell Position : 39,102,-100
+ dim 1, 3, 
+```
 
 
 
diff --git a/src/docs/part2/adding_detectors.md b/src/docs/part2/adding_detectors.md
index b13e1d8242c94f897e79b328d6d28d06ce876a08..11692dcfd2fc0d761c117e6b8b3c2a90adbe6307 100644
--- a/src/docs/part2/adding_detectors.md
+++ b/src/docs/part2/adding_detectors.md
@@ -43,19 +43,17 @@ Building a new (generic) detector using dd4hep is rather straight forward if we
 make the following assumptions.
 
 1. We will use the built-in sensitive detectors
-2. We will use the built-in data model (hits) associated with these detectors
+2. We will use the dd4pod data model (i.e. use `npsim`)
 
-These items can be customized by using the DD4hep plugin mechanism. This will 
-be covered in another tutorial.
 
 ### Compiling a new detector
 
 For this tutorial we will build a simplified Roman Pot detector.
 We will discuss the detector built in the source file
-`src/GenericDetectors/src/SimpleRomanPot_geo.cpp`.
+`src/MyDetector.cpp`.
 To compile this detector into the GenericDetectors library the detector needs 
 to be added to the list of sources in the cmake file 
-`src/GenericDetectors/CMakeLists.txt`.
+`CMakeLists.txt`.
 
 ```bash
 dd4hep_add_plugin(${a_lib_name} SOURCES
@@ -89,7 +87,7 @@ The argument signature of the `build_detector` is:
 - `SensitiveDetector sens`: The sensitive detector to be assigned to the 
   sensitive volumes/elements of the detector. 
 
-The DD4hep plugin macro `DECLARE_DETELEMENT(SimpleRomanPot, build_detector)` 
+The DD4hep plugin macro `DECLARE_DETELEMENT(MyDetector, build_detector)` 
 stamps out the necessary boiler plate code to register a new detector called 
 `SimpleRomanPot` which is build by calling `build_detector`.
 
@@ -99,15 +97,15 @@ The `<detector>` tag defines a new instance of a detector and requires the
 attributes "id", "name", and "type". For example:
 
 ```xml
-<detector id="1" name="MyRomanPot" type="SimpleRomanPot"
-          vis="RedVis" readout="RomanPotHits" zoffset="1.0*m">
+<detector id="1" name="aNeatDetector" type="MyDetector"
+          vis="RedVis" readout="MyDetectorHits" zoffset="1.0*m">
 </detector>
 ````
 
-This defines an instance of the detector named "MyRomanPot" of type 
-"SimpleRomanPot" (i.e. the type-name given in the first argument of the DD4hep 
-`DECLARE_DETELEMENT` macro) and with id=1. The additional attributes (vis, 
-readout, zoffset) will are optional.
+This defines an instance of the detector named "aNeatDetector" of type 
+"MyDetector" (i.e. the type-name given in the first argument of the DD4hep 
+`DECLARE_DETELEMENT` macro) and with id=1. Each `<detector>` must have a unique id.
+The additional attributes (vis, readout, zoffset) are optional.
 
 The detector tag is provided as the second argument in the `build_detector` 
 function. It can be parsed *how ever you want* in order to extract detector 
@@ -115,7 +113,6 @@ information. The allowed attributes are listed in
 [`UnicodeValues.h`](http://test-dd4hep.web.cern.ch/test-dd4hep/doxygen/html/_unicode_values_8h_source.html) 
 where it is clear how to add new attributes.
 
-
 #### Geometry Construction
 
 If you are familiar with Geant4 or TGeo geometry construction then this will be