A type SReal exists in Sofa, giving a default type for floating point variables. Depending on the Sofa Configuration, it can be simple or double precision.
If your component has a "Data" dedicated to visualization purpose, making its name beginning with show will place it inside the Visualization tab, displayed when you try to modify a component in the GUI.
Add a link to an example scene in the Modeler
To have an example linked inside the Modeler, you have to create a .scn file with the exact same name as your component. It must be placed in examples/Components and a subdirectory corresponding to its base class (forcefield, constraint, ...)
Graphic Documentation of a special Scene
To pop-up a small documentation of a scene, when loaded in Sofa, you need to create a .html file, with the same name as your .scn file. An example can be found for examples/Demos/chainHybridNoGroup.scn.