geom/doc/salome/gui/GEOM/input/creating_curve.doc

/*!

\page create_curve_page Curve

To create a \b Curve in the <b>Main Menu</b> select <b>New Entity - >
Basic - > Curve</b>

There are three <b>Curve Construction</b> menu choices corresponding to three
possible types of curves: Polyline, Besier or B-spline (Interpolated).
The curve is defined by a list of \b Points through which it passes.


\n There are two ways to define these <b>Points</b>:
<ul>
<li> <b>By Selection</b> manual picking of the points in the Object Browser or 3D Viewer.
<li> <b>Analytical</b> parametric definition of the points through
python expressions.
</ul>

\n The \b Result of each operation will be a GEOM_Object (edge).

<b>Polyline</b>

\image html polyline.png

Polyline or polygonal chain is a connected series of line segments. It
can be defined by the following parameters:

\image html curve2.png

<ul>
<li><b>Points</b> at least 2 points which will serve as nodes on the curve.</li>
<li><b>Build a closed wire</b> checkbox allows creating the curve as
closed wire.</li>
</ul>

\n <b>TUI Command:</b> <em>geompy.MakePolyline(ListOfShapes,isClosed)</em>

<b>Bezier</b>

\image html bezier.png

Bezier curve is a curve completely contained in a convex hull of its
control points. It can be defined by the following parameters:


\image html curve3.png

<ul>
<li><b>Points</b> at least 2 points used to approximate the curve.</li>
<li><b>Build a closed edge</b> checkbox allows creating the curve as
closed edge.</li>
</ul>

\n <b>TUI Command:</b> <em>geompy.MakeBezier(ListOfShapes,isClosed)</em>

<b>B-spline</b>

\image html interpol.png

B-spline is a union of curve segments defined at each node span. It
can be defined by the following parameters:

\image html curve4.png

<ul>
<li><b>Points</b> at least 2 points which will serve as nodes on the curve.</li>
<li><b>Build a closed edge</b> checkbox allows creating the curve as
closed edge.</li>
<li> If <b>Reorder vertices taking into account distances</b> is
checked, the interpolation algorithm does not follow the order of
vertices but searches for the closest vertex.</li>
<li><b>Tangents</b> are two vectors, defining the direction at the ends of the
curve. It is necessary to set both vectors or none. This option is available only
if both above check boxes are not checked.
</li>
</ul>

\n <b>TUI Command:</b>
<br><em>geompy.MakeInterpol(ListOfShapes,isClosed,doReordering)</em>
<br><em>geompy.MakeInterpolWithTangents(ListOfShapes,Vector1,Vector2)</em>

<b>Analytical Definition</b>

The input parameters for analytical definition are common for all
types of curves. 

\image html curve1.png

<ul>
<li><b>X(t)equation, Y(t)equation, Z(t)equation</b> are python
expressions for X, Y and Z coordinates of the basic points of the curve.</li>
<li><b>Min t, Max t</b> are minimum and maximum values of the parameter \b t.</li>
<li><b>Step</b> is the number of steps of the parameter \b t.</li>
</ul> 

\n <b>TUI Command:</b> <em>geompy.MakeCurveParametric(XExpr, YExpt, ZExpt, tMin, tMax, nbSteps, curveType, True)</em>

\n<b>Advanced options</b> \ref preview_anchor "Preview"

Our <b>TUI Scripts</b> provide you with useful examples of creation of 
\ref tui_creation_curve "Basic Geometric Objects".

*/