These functions are used to select the current element of a scene (environment, obstacle, robot, trajectory) or to get information on this current element.
The function int p3d_get_desc_number(int type) returns the number of elements of type type (P3D_ENV, P3D_OBSTACLE, P3D_ROBOT, P3D_BODY, P3D_TRAJ).
The functions char *p3d_get_desc_curname(int type) , void *p3d_get_desc_curid (int type) and int p3d_get_desc_curnum(int type) return the name, pointer and number of the current element of type type.
The current element can been changed by selecting another element of the description. The functions void *p3d_sel_desc_name(int type, char* name) , void *p3d_sel_desc_num(int type, int num) and void *p3d_sel_desc_id(int type, void *id) select the element of type type, of name name, of number num or of pointer id, and returns this element.