diff --git a/doc/RTD/source/ParameterFiles/output_selection.rst b/doc/RTD/source/ParameterFiles/output_selection.rst
index b84a776c7dcac2136dedd2324cfef43d7a5455ea..728079023b937d699819e595d18b5a233773c29b 100644
--- a/doc/RTD/source/ParameterFiles/output_selection.rst
+++ b/doc/RTD/source/ParameterFiles/output_selection.rst
@@ -6,12 +6,11 @@
Output List
~~~~~~~~~~~
-In the sections ``Snapshots`` and ``Statistics``, you can specify the
-options ``output_list_on`` and ``output_list`` which receive an int
-and a filename. The ``output_list_on`` enable or not the output list
-and ``output_list`` is the filename containing the output times. With
-the file header, you can choose between writing redshifts, scale
-factors or times.
+In the sections ``Snapshots``, ``Statistics`` and ``StructureFinding``, you can
+specify the options ``output_list_on`` and ``output_list`` which receive an int
+and a filename. The ``output_list_on`` enable or not the output list and
+``output_list`` is the filename containing the output times. With the file
+header, you can choose between writing redshifts, scale factors or times.
Example of file containing with times (in internal units)::
diff --git a/doc/RTD/source/ParameterFiles/parameter_description.rst b/doc/RTD/source/ParameterFiles/parameter_description.rst
index 0454d30a6139a9b43b09908b7ba44155d37f11b4..9f2ed813accc3e4aa91b2b916fb0c27a391544ee 100644
--- a/doc/RTD/source/ParameterFiles/parameter_description.rst
+++ b/doc/RTD/source/ParameterFiles/parameter_description.rst
@@ -438,7 +438,7 @@ in the internal units of time. Users also have to provide the difference in time
In non-cosmological runs this is also expressed in internal units. For
cosmological runs, this value is *multiplied* to obtain the
scale-factor of the next snapshot. This implies that the outputs are
-equally space in :math:`\log(a)` (See :ref:`Output_list_label` to have
+equally spaced in :math:`\log(a)` (See :ref:`Output_list_label` to have
snapshots not regularly spaced in time).
When running the code with structure finding activated, it is often
@@ -935,8 +935,8 @@ to control whether they are used or not. If enabled these will be used to
repartition after the second step, which will generally give as good a
repartition immediately as you get at the first unforced repartition.
-Also once these have been enabled you can change the `trigger:` value to
-numbers greater than 2, and repartitioning will be forced every `trigger`
+Also once these have been enabled you can change the ``trigger`` value to
+numbers greater than 2, and repartitioning will be forced every ``trigger``
steps. This latter option is probably only useful for developers, but tuning
the second step to use fixed costs can give some improvements.
@@ -945,7 +945,70 @@ the second step to use fixed costs can give some improvements.
Structure finding (VELOCIraptor)
--------------------------------
+This section describes the behaviour of the on-the-fly structure
+finding using the VELOCIraptor library (see
+:ref:`VELOCIraptor_interface`). The section is named
+``StructureFinding`` and also governs the behaviour of the
+structure finding code when invoked at snapshots dumping time via
+the parameter ``Snapshots:invoke_stf``.
+The main parameters are:
+
+ * The VELOCIraptor parameter file to use for the run:
+ ``config_file_name``,
+ * The directory in which the structure catalogs will be written: ``basename``.
+
+Both these parameters must always be specified when running SWIFT with
+on-the-fly calls to the structure finding code. In particular, when
+only running VELOCIraptor when snapshots are written, nothing more is
+necessary and one would use:
+
+.. code:: YAML
+
+ Snapshots:
+ invoke_stf: 1 # We want VELOCIraptor to be called when snapshots are dumped.
+ # ...
+ # Rest of the snapshots properties
+
+ StructureFinding:
+ config_file_name: my_stf_configuration_file.cfg # See the VELOCIraptor manual for the content of this file.
+ basename: ./haloes/ # Write the catalogs in this sub-directory
+
+If one additionally want to call VELOCIraptor at times not linked with
+snapshots, the additional parameters need to be supplied.
+
+The time of the first call is controlled by the two following options:
+
+* Time of the first call to VELOCIraptor (non-cosmological runs): ``time_first``,
+* Scale-factor of the first call to VELOCIraptor (cosmological runs): ``scale_factor_first``.
+
+One of those two parameters has to be provided depending on the type of run. In
+the case of non-cosmological runs, the time of the first call is expressed
+in the internal units of time. Users also have to provide the difference in time
+(or scale-factor) between consecutive outputs:
+
+* Time difference between consecutive outputs: ``delta_time``.
+
+In non-cosmological runs this is also expressed in internal units. For
+cosmological runs, this value is *multiplied* to obtain the
+scale-factor of the next call. This implies that the outputs are
+equally spaced in :math:`\log(a)` (See :ref:`Output_list_label` to have
+calls not regularly spaced in time).
+
+Showing all the parameters for a basic cosmologica test-case, one would have:
+
+.. code:: YAML
+
+ StructureFinding:
+ config_file_name: my_stf_configuration_file.cfg # See the VELOCIraptor manual for the content of this file.
+ basename: ./haloes/ # Write the catalogs in this sub-directory
+ scale_factor_first: 0.1 # Scale-factor of the first output
+ delta_time: 1.1 # Delta log-a between outputs
+
+
+------------------------
+
+
.. [#f1] The thorough reader (or overly keen SWIFT tester) would find that the speed of light is :math:`c=1.8026\times10^{12}\,\rm{fur}\,\rm{ftn}^{-1}`, Newton's constant becomes :math:`G_N=4.896735\times10^{-4}~\rm{fur}^3\,\rm{fir}^{-1}\,\rm{ftn}^{-2}` and Planck's constant turns into :math:`h=4.851453\times 10^{-34}~\rm{fur}^2\,\rm{fir}\,\rm{ftn}^{-1}`.
diff --git a/doc/RTD/source/VELOCIraptorInterface/index.rst b/doc/RTD/source/VELOCIraptorInterface/index.rst
index 312b9cd3f893dd44f814ad80ac40748db12bd4d5..2ef4533ca8d1f5e47f01b761b68528e9040048a2 100644
--- a/doc/RTD/source/VELOCIraptorInterface/index.rst
+++ b/doc/RTD/source/VELOCIraptorInterface/index.rst
@@ -1,6 +1,8 @@
.. VELOCIraptor Interface
Folkert Nobels, 8th October 2018
+.. _VELOCIraptor_interface:
+
VELOCIraptor Interface
======================