--- a
+++ b/Docs/Scaling/intro.md
@@ -0,0 +1,99 @@
+(scaling-intro)=
+
+# Introduction to Scaling
+
+:::{sidebar} Scaling Tutorials
+
+The three tutorials covers the different scaling 
+methods shown in the table below:
+
+```{toctree}
+:maxdepth: 1
+
+lesson1
+lesson2
+lesson3
+
+```
+:::
+
+Musculoskeletal models must be scalable to sizes of different
+individuals to be useful for product design. Scaling pertains not only to the overall geometry,
+but also muscle insertion points, muscle parameters, wrapping
+surfaces etc. AnyBody has a both generic and user-define scaling laws for models in the repository.
+
+For details on scaling theory behind please take a look at [Rasmussen 2005](https://paperpile.com/shared/sqkoXwnHARTiI82J2Sarhcg).
+
+Size related parameters of models in the {doc}`AMMR </index>`
+are seldom defined as constant numbers, but instead computed from global measurements
+(e.g., total height, weight of human) based on a scaling law. Thus all body models
+expect the definition of a scaling law, although user can
+choose the actual law.
+
+Currently there are six pre-defined scaling laws available in AnyBody:
+
+
+```{eval-rst}
+.. list-table::
+   :widths: 3 7
+   :header-rows: 1
+
+   * - Scaling law
+     - Description
+   * - :any:`ScalingStandard <_SCALING_STANDARD_>`
+     - scale to a standard size; i.e. use 50th percentile sizes for a European male
+   * - :any:`ScalingNone <_SCALING_NONE_>`
+     - do not scale; i.e. use underlying cadaveric dataset as is
+   * - :any:`ScalingUniform  <_SCALING_UNIFORM_>`
+     - cale segments equally in all directions; input is joint to
+       joint distances
+   * - :any:`ScalingLengthMass <_SCALING_LENGTHMASS_>`
+     - scale taking mass into account; input is joint to
+       joint distances and mass
+   * - :any:`ScalingLengthMassFat <_SCALING_LENGTHMASSFAT_>`
+     - scale taking mass and fat into account; input
+       is joint to joint distances
+   * - :any:`ScalingXYZ  <_SCALING_XYZ_>`
+     - scale taking mass and fat into account; scale segments along X, Y, Z axes;
+       input is scale factors along X, Y, Z axes.
+```
+
+**Please also notice that each scaling law scales the strength of the
+muscles, in addition to the size and mass of the bone.** This strength
+scaling is done automatically in most cases. We will come back to it
+when needed. Users who need a more comprehensive introduction can view
+this recorded previous webcast titled [“Anthropometrical Scaling of
+Musculoskeletal
+Models”](https://www.anybodytech.com/download/anthropometrical-scaling-of-musculoskeletal-models).
+
+## Overwriting default input parameters
+
+After selecting a scaling law, the user can override the default input
+parameters. All input parameters can be accesed in the
+`Main.HumanModel.Anthropometrics` folder.
+
+For example, to adjust the height of
+the model, the user can add the following code to the `Main` file:
+
+```AnyScriptDoc
+Main.HumanModel.Anthropometrics.BodyHeight = 1.8; // overwrites the default value
+```
+
+### Using legacy `AnyMan.any` files
+
+To keep backward compatibility with older models, AnyBody still supports using custom `AnyMan.any` files.
+You can specify your own file with by setting the `BM_SCALING_ANTHRO_FILE` BM statement:
+
+```AnyScriptDoc
+#path BM_SCALING_ANTHRO_FILE "My_Own_AnyMan.any"
+```
+
+This method is not recommended for new models, but it is still supported for older models.
+
+:::{admonition} **Next lesson:**
+:class: seealso
+Now head for {doc}`lesson1`.
+:::
+
+% ..  image:: _static/intro/image1.jpeg
+%     :width: 80%