Parameters entries and expected formatting

MVSim uses a custom parameter parsing system defined in TParameterDefinitions and TParamEntry classes. This system extends standard C sscanf format specifiers with additional types commonly used in robotics and simulation.

Parameters can be defined in XML as either:

• XML attributes: <block mass="50.0" static="true"/>

• XML child elements: <block><mass>50.0</mass><static>true</static></block>

Both forms are equivalent and parsed using the same system.

All those defined by standard sscanf, plus these extensions:

MVSim extensions to sscanf formats

Format specifier	C++ pointer to…	Expected format
%lf_deg	double	A number, in degrees.
%s	std::string	A string. Whitespace will be trimmed.
%color	mrpt::img::TColor	A color like #RRGGBB[AA] ([00-FF] each)
%pose2d	mrpt::poses::CPose2D	Expects X Y YAW_DEG
%pose2d_ptr3d	mrpt::poses::CPose3D	Expects X Y YAW_DEG
%pose3d	mrpt::poses::CPose3D	Expects X Y Z YAW_DEG PITCH_DEG ROLL_DEG
%point3d	mrpt::math::TPoint3D	Expects X Y Z YAW_DEG PITCH_DEG ROLL_DEG
%bool	bool	Expects true, false, 1, or 0 (case-insensitive)

Special handling

NaN values

Some parameters use NaN (Not a Number) as a sentinel value to indicate “not set” or “use default”. For example:

• Block visual_scale: NaN means use the class-defined model_scale

• Block zmin / zmax: NaN means auto-calculate from visual model

When parameters have default NaN values, omitting them in XML leaves them as NaN, which triggers the appropriate fallback behavior.