Graphics3D[
{
  {RGBColor[0,0,1], PointSize[0.02], Point[{0.5,0,0}]},
  {RGBColor[1,0,0], Line[{{0,-1,0}, {1,0,0}}]},
  {RGBColor[0,1,0], Line[{{1,0,0}, {0,0,1}}]},
  {Polygon[{{0,0.4,0}, {0,0,0}, {0.3, 0, -0.4}}]}

},{Boxed -> False}]