A SOFA component is a class or a class template that inherits, directly or not, from
sofa::core::objectmodel::BaseObject. A component must also respect some conventions:
- the declaration must begin with the
SOFA_CLASSmacro. It will expand to some code required by SOFA, that will enable some kind of reflection mechanisms;
- a component must be registered in the
ObjectFactory, using the
RegisterObjectmechanism (see example below), otherwise SOFA won’t be aware of it.
Here is a minimal example, for a component that does nothing:
Once the plugin is compiled, this component can be used in an XML scene file. You should also add a
RequiredPlugin element in the root node in order to load
MyPlugin when the scene is loaded.
This is a basic example; most components don’t inherit directly from
BaseObject, but from a subclass which represent a specific aspect of a simulation. For example, force field components inherit from
sofa::core::BaseForcefield, or one of its subclasses.
Add Data to your component
Almost every component has parameters, inputs, or outputs: they are referred to as Data; in a scene file, those are the XML attributes of the component. Each XML attribute of a component is actually a member of the class, declared in a special way: it is encapsulated in a Data. For example, in order to add a float Data named
myparam to our component, we will add this member to
Then we must register and initialise it in each Constructor of MyComponent:
This allows us to use this Data in scene files; it can be assigned a value like so:
Last modified: 30 November 2021