trace_t

struct trace_t
  Vector         startpos;            // start position
  Vector         endpos;              // final position
  cplane_t       plane;               // surface normal at impact
  float          fraction;            // time completed, 1.0 = didn't hit anything
  int            contents;            // contents on other side of surface hit
  unsigned short dispFlags;           // displacement flags for marking surfaces with data
  bool           allsolid;            // if true, plane is not valid
  bool           startsolid;          // if true, the initial point was in a solid area
  float          fractionleftsolid;   // time we left a solid, only valid if we started in solid
  csurface_t     surface;             // surface hit (impact surface)
  int            hitgroup;            // 0 == generic, non-zero is specific body part
  short          physicsbone;         // physics bone hit by trace in studio
  unsigned short worldSurfaceIndex;   // Index of the msurface2_t, if applicable
  IClientEntity* hit_entity;
  int            hitbox;              // box hit by trace in studio
};