Surface GeomFillSurface

Description
creates a parametric surface from two, three, or four boundary edges, trying to create a smooth transition between them.







Usage

 * 1) Press the  button.
 * 2) Select edges in the 3D view. The edges must connect together so that they formed a closed profile.
 * 3) Press.

once created, it is not possible to apply additional constraints to the created surface.

Options

 * ,, or.

Properties
A Surface GeomFillSurface ( class) is derived from the basic Part Feature ( class, through the subclass), therefore it shares all the latter's properties.

In addition to the properties described in Part Feature, the Surface Filling has the following properties in the property editor.

Data

 * the applied filling algorithm; Stretch, the style with the flattest patches;, a rounded style with less depth than Curved; Curved, the style with the most rounded patches.
 * a list of edges that will be used to build the surface.

View

 * : it defaults to ; if set to, it will show an overlay with the control points of the surface.

Twisting of the surface
The shape of the surface depends on the direction of the chosen edges; if edges are selected and the result is a surface that "twists" on itself, one of the edges may need its list of vertices in the reverse order. A surface that twists on itself will probably have self-intersections, and thus will be an invalid Shape; this can be verified with.

For example, if two curves have the points

and the resulting surface after using or  is a twisted surface, you may create a third curve that is equal to one of the two original curves but with a reversed list of points.

Either

or

should work to generate a surface that doesn't twist.

In practical terms this means that all edges used to generate a surface should be created preferably in the same clockwise or anti-clockwise direction. Following this simple rule usually guarantees that the surface will follow the smoothest direction and won't twist.

When the surface's property is, a face will be painted completely black if its normal direction points into the 3D view (away from the current viewer), indicating a flipped face with respect to the other colored faces.



Scripting
FreeCAD Scripting Basics.

The Surface GeomFillSurface tool can be used in macros and from the Python console by adding the object.
 * The edges to be used to define the surface must be assigned as a LinkSubList to the property of the object.
 * The type of algorithm must be assigned like a string to the property.
 * All objects with edges need to be computed before they can be used as input for the properties of the GeomFillSurface object.