BSpline Surface


A surface defined using the standard BSpline definition based on the capabilities of the Mesh entity representing the control polygon. The surface supports the non-uniform knot vector but not the rational capabilities of NURBS. However, surface developed entirely interactively remain uniform. Multiple BSpline Surfaces can be combine into groups (BSplineSurfaceList) to optimise screen updates when not requiring manipulation. The BSpline Surface can be converted into a Facet surface (PolygonList), used to create Calculation Sections for hydrostatics calculations or the surface converted into a Mesh instance.


Menu: Create -> BSpline Surface... / Create -> Drag BSpline Surface.

Interactively create a BSpline Surface by Left-Clicking to draw a rectangle defining the corner points of the control polygon. The initial orientation of surface will be defined on the Default Edit Plane. Alternatively, the Create BSpline Surface dialog box can be used to define the surface and orientation parametrically.

See Also:-

Interactive Editing

Edit mode is entered by pressing F2 displaying the control polygon of the surface. The control points of the entity are selected and edited using the PolyCAD standard surface manipulation techniques.

See Also:-

Entity Attributes Panel

BSpline Surface Attributes Panel

Edit Menu

Multi-Select Menu

Display Options

Short Cuts

File Format


Import / Export

Format Import Export
AutoCAD DXF Yes as Mesh
Initial Graphics Exchange Spec. (IGES) Yes Yes
Defcar - ShipGEN Template Yes  
FastShip (SRF) Yes Yes
ACIS (Autodeck/Tribon/Aveva Marine Initial Design) Yes Yes