Skip to content

lesson1.md

Latest commit

 

History

History
265 lines (201 loc) · 8.09 KB

lesson1.md

File metadata and controls

265 lines (201 loc) · 8.09 KB

::: {rst-class} break :::

Lesson 1: Creating a Standing Model

The standing model can be found in the AMMR folder under Applications/Examples. The main file is called StandingModel.Main.any.

While this file can be opened with the "File->Open" menu in AnyBody, do not do this! This tutorial will teach you an easier way to use the Standing Model as a starting template.

Key (modifiable) features of the standing model are:

  • Both feet are always connected to the ground.
  • The posture is defined by the joint angles for all major joints except the ankles.
  • The model automatically balances itself by maintaining its center of mass vertically above the ankle joints. For example, if the arms move forward, the entire body moves backward to maintain balance.
  • External forces can be applied to predefined nodes on the model. Muscle forces may change to resist these forces and maintain balance.

(model-templates)=

Model templates

To create a new standing model using the template model in the AMMR, click the "Create New from template" button Model_button in the toolbar:

:alt: Toolbar
:class: bg-primary
:align: center

The Template dialogue opens and displays a list of pre-defined templates supported in the AMMR.

Choose the "Human Standing" template and select the folder you want to save your new Human Standing model in. To demonstrate, let us save the model in the 'AnyBody.{{ AMS_VERSION_X }}/AMMR.v{{ AMMR_VERSION }}-Demo' directory which we extracted in the {doc}introduction <intro> of this tutorial.

Give the model a name, for example {file}MyStandingHuman, and press OK to save.

:alt: Template
:class: bg-primary
:align: center

Your new ‘MyStandingHuman.main.any’ file opens in the script Editor. The location of the file is shown in the title bar:

:alt: Script editor
:class: bg-primary
:align: center

:::{warning} If you saved your model in another location be sure to modify the {file}../libdef.any file so it points to AMMR repository you want to use.

The following line should always refer correctly to the libdef file regardless of where you save your model.

#include "<ANYBODY_PATH_INSTALLDIR>/AMMR/libdef.any"

:::

(loading-a-model)=

Loading a model

To see the 3D graphical representation of the model you need to load.

Load/reload is a frequent operation and has been assigned to function key F7. You may also load your model by clicking Load in the toolbar.

This action will load whatever file is chosen in the text editor. If a file is already loaded, the above action will simply reload the file until you give another file loading priority by right-clicking its tab and select “Load Model”.

:alt: Load Model
:class: bg-primary
:align: center

The model view

When loading is completed, the Model View window opens and shows the standing model. You can open it manually from View -> Model Views.

:alt: Model view
:class: bg-primary
:align: center

The icons in the toolbar at the top of the Model View window allow you to modify the image: zoom, pan, rotate, etc. They should be mostly self-explanatory. Now is a good time to play a bit around with them and to familiarize yourself with the options.

In practical use it is often necessary to change quickly between these functions, so keyboard shortcuts have been provided:

  • The Ctrl button activates the Pan function.
  • The Shift button activates the Zoom function.
  • The Ctrl-Shift combination activates the rotation function.
  • If you have a scrolling wheel on your mouse, this will zoom the model in and out.

Understanding the AnyScript Model Structure

This Human Standing Model is a model from the AnyBody Managed Model Repository (AMMR). It uses the Human Model from the AMMR, which is used by most models you will encounter when using the AMMR. Regardless of complexity, all models share a common structure used to set them up.

The models will typically have the following overall structure (notice, the AnyScript below is not excatly the same as the Standing Model used in this tutorial, but contains the same overall structure):

// Include the libdef file from the AMMR
#include "libdef.any"

Main =
{
  // Define the BodyModel configuration
  #include "Model/BodyModelConfiguration.any"

  // Include the Human model from AMMR
  #include "<ANYBODY_PATH_BODY>/HumanModel.any"

  // Define desired posture or movement of the model
  #include "Model\Mannequin.any"

  // Compose the model
  AnyFolder Model =
  {
    AnyFolder &BodyModel = .HumanModel.BodyModel;
    AnyFolder Drivers = {...};
    AnyFolder Environment = {...};
  };

  // Configuring the Study
  AnyBodyStudy Study =
  {
    AnyFolder &Model= .Model;
    Gravity = {0.0, -9.81,0.0}; // Gravity Vector
    nStep = 10; // Number of steps
    tStart = 0; // Start time
    tEnd = 10.0; // End time
  };
};

Let us go through the different components of this structure to understand how they work.

Path to AMMR:

:::{note} :class: margin You can open a file by double-clicking on its name in the AnyScript. :::

#include "libdef.any"

This means your model will include the content of the file called libdef.any. This file references to another libdef.any file located at the top-level folder of the AMMR, which specifies the AMMR directories to use in your model. You can have multiple versions of AMMR available on your computer, and this points to the version you wish to use. This line should be at the very beginning of your main.any file.

Configuring the Human Model:

Main =
{
  // Define the BodyModel configuration
  #include "Model/BodyModelConfiguration.any"

Here, the main declaration of the model, Main = {}, is initiated, and this file now becomes the main model file. All basic AnyScript contains a main file that defines the model’s structure, contents and the operations to be performed.

The file BodyModelConfiguration.any is included, which defines what parts of the human body model are included, through a number of switches called Body Model (BM) parameters. BM parameters are always prefixed with BM_ inside AnyScript. The values of these parameters are defined by #define and #path statements.

Including the Human Model

#include "<ANYBODY_PATH_BODY>/HumanModel.any"

The AMMR contains multiple musculoskeletal models. The above line includes the Human Model from the AMMR. The file path <ANYBODY_PATH_BODY> is defined in libdef.any.

It is important that the above configuration statements are placed before this line.

Defining the Posture and Movement

#include "Model\Mannequin.any"

This includes the file Mannequin.any which defines the posture and movement of the human body model.

Composing the Model

AnyFolder Model =
{
  AnyFolder &BodyModel = .HumanModel.BodyModel;
  AnyFolder Drivers = {...};
  AnyFolder Environment = {...};
};

This is where we combine the Body from the Human Model with extra things like drivers, external loads, and constraints. It could also be any models of the environment which the body interacts with or many other things.

The Study section

AnyBodyStudy Study =
{
  AnyFolder &Model= .Model;
  Gravity = {0.0, -9.81,0.0}; // Gravity Vector
  nStep = 10; // Number of steps
  tStart = 0; // Start time
  tEnd = 10.0; // End time
};

The AnyBodyStudy is where you configure and define your simulation. It specifies start and end times of the simulation, and the number of steps. It also configures which solvers are used.

Only the model elements which are referenced to within the Study will be included in the simulation. In this case, the line AnyFolder &Model= .Model; references to the Model folder, meaning everything in the Model folder is part of the simulation.

You can now proceed to {doc}lesson2.