Instructions

To use the DSC method, simply follow these few steps:

Step 1: Setup

It is recommended to use the setup (drawing, logging etc.) provided in the DEMO folder (the demo.cpp, user_interface.h, user_interface.cpp and draw.h source files). However, if you want another setup, you can use the default setup as starting point.

Step 2: Create your own velocity function class

Create a your own velocity function class which extends the VelocityFunc class. This class should as minimum override the get_name() and deform() functions. The get_name() function should return a string with the name of the velocity function and the deform() function should have the following signature:

• For each interface node **n** in the dsc
  

  •   Calculate a new position **p** according to the velocity function
    

  •   Call `set_destination(n, p)`
    

• Call `deform()`
  

Three examples of velocity functions can be found in the repository in the DEMO folder: A rotation function (rotate_function.h), a function which smooths the model (average_function.h) and a function which moves the interface in the normal direction (normal_function.h).

Step 3: Create a new initialisation function

Several default initialisation functions are provided with the DEMO application (for example rotate_cube(), smooth_armadillo() and expand_armadillo()). Use these as your starting point when creating a new initialisation function. An initialisation function should contain the following:

• Generate (using the Tetralizer class) or import (using the import_tet_mesh_() function) a 3D model.
• Optional: Create a new instance of the DesignDomain class (defining the design domain).
• Create a new instance of the DeformableSimplicialComplex class.
• Create a new instance of a velocity function class (for example the one created in step 2).
• Optional: Create a new instance of the Log class.

Note: If you use the default setup in the DEMO application, you have to add the initialisation function to the keyboard_() function.

Step 4 (optional): Add custom simplex attributes.

If your application requires attributes to be stored at each simplex (each node, edge, face or tetrahedron), extend the corresponding attribute class found in attributes.h and give this as a template parameter when instantiating the DeformableSimplicialComplex class instead of the default attribute class. For example, let us say that our application requires a double value called x to be stored at each node. We then extend the NodeAttributes class and add x as a variable to this new class. This could look like this:

template<typename MT>
class MyNodeAttributes: public NodeAttributes<MT> {
    double x;
public:
    double get_x(){
        return x;
    }

    void set_x(double _x) {
        x = _x;
    }
};

We then give MyNodeAttributes as a template parameter to the DeformableSimplicialComplex class instead of the default NodeAttributes class:

dsc = new DeformableSimplicialComplex<MT, MyNodeAttributes<MT>>(DISCRETIZATION, points, tets, tet_labels);

Step 5 (optional): Change the DSC parameters

When the DeformableSimplicialComplex object is constructed, several parameters are set to control the min/max edge length, min/max angle etc. of the simplicial complex. You can change these parameters by extending the DeformableSimplicialComplex class and override the constructor.