--- /dev/null
+.. |bspline.icon| image:: images/bspline.png
+.. |bspline_p.icon| image:: images/bspline_p.png
+.. |add_pole.icon| image:: images/bspline_add_pole.png
+
+B-spline and periodic B-spline
+==============================
+
+The feature creates a free form spline curve in the current Sketch.
+
+To add a new B-spline to the Sketch:
+
+#. select in the Main Menu *Sketch - > B-spline* item or
+#. click |bspline.icon| **B-spline** button in the Sketch toolbar.
+
+To add a periodic B-spline to the Sketch:
+
+#. select in the Main Menu *Sketch - > Periodic B-spline* item or
+#. click |bspline_p.icon| **Periodic B-spline** button in the Sketch toolbar.
+
+
+Creation of B-spline curve
+""""""""""""""""""""""""""
+
+.. image:: images/bspline_creation_panel.png
+ :align: center
+
+Click in the view to specify the control polygon of B-spline curve. The curve will be shown after the second point is initialized. To stop adding new poles, click **Esc** button or **Apply** the operation.
+
+
+**TUI Command**:
+
+.. py:function:: Sketch_1.addSpline(degree, poles, weights, knots, multiplicities, periodic)
+
+ :param integer: degree of B-spline.
+ :param array: list of poles [(x1, y1), (x2, y2), ...].
+ :param array: list of weights for corresponding poles.
+ :param array: parametric knots of B-spline curve.
+ :param array: multiplicity of each knot.
+ :param boolean: True mentions that the B-spline curve is periodic.
+ :return: Result object.
+
+Each parameter is optional.
+
+Result
+""""""
+
+Created B-spline curve appears in the view.
+
+.. image:: images/bspline_result.png
+ :align: center
+
+.. centered::
+ Non-periodic B-spline created
+
+
+.. image:: images/bspline_periodic_result.png
+ :align: center
+
+.. centered::
+ Periodic B-spline created
+
+**See Also** a sample TUI Script of :ref:`tui_create_bspline` operation.
+
+
+Modification of B-spline curve
+""""""""""""""""""""""""""""""
+
+.. image:: images/bspline_modification_panel.png
+ :align: center
+
+.. centered::
+ Modification panel for B-spline curve
+
+The following options are provided to modify the already created B-spline curve:
+
+#. Change weight of each pole.
+#. Add new pole.
+
+The new pole is added after the current by pressing on the corresponding |add_pole.icon| button. The default weight for the new pole is 1.
+
+**Note:** adding the new pole after the last for non-periodic B-spline will not change the last point of the curve to avoid modification of full sketch.
--- /dev/null
+from salome.shaper import model
+
+model.begin()
+partSet = model.moduleDocument()
+Sketch_1 = model.addSketch(partSet, model.defaultPlane("XOY"))
+
+SketchBSpline_1_poles = [(-70, -5), (-50, 30), (-40, 3), (-20, 20), (-10, -5)]
+SketchBSpline_1 = Sketch_1.addSpline(poles = SketchBSpline_1_poles, weights = [1, 2, 2, 2, 1])
+[SketchPoint_1, SketchPoint_2, SketchPoint_3, SketchPoint_4, SketchPoint_5] = SketchBSpline_1.controlPoles(auxiliary = [0, 1, 2, 3, 4])
+[SketchLine_1, SketchLine_2, SketchLine_3, SketchLine_4] = SketchBSpline_1.controlPolygon(auxiliary = [0, 1, 2, 3])
+
+SketchBSplinePeriodic_1_poles = [(10, -5), (30, 30), (40, 3), (60, 20), (70, -5)]
+SketchBSplinePeriodic_1 = Sketch_1.addSpline(poles = SketchBSplinePeriodic_1_poles, weights = [3, 2, 1, 1, 1], periodic = True)
+[SketchPoint_6, SketchPoint_7, SketchPoint_8, SketchPoint_9, SketchPoint_10] = SketchBSplinePeriodic_1.controlPoles(auxiliary = [0, 1, 2, 3, 4])
+[SketchLine_5, SketchLine_6, SketchLine_7, SketchLine_8, SketchLine_9] = SketchBSplinePeriodic_1.controlPolygon(auxiliary = [0, 1, 2, 3, 4])
+
+model.do()
+model.end()
