CoCreate OneSpace Designer - Commands Reference Manual

BSPLINE_INT terminate action

BSPLINE_INT specifies a B-spline using a sequence of interpolation points, through which the curve will pass.

Syntax


                         +---------------<---------------+
                         v                               |
----->(BSPLINE_INT)------+--->|data position|--------->--+---->
                         |                               |
                         +--->(:CLOSED)--------------->--+
                         |                               |
                         +--->(:OPEN)----------------->--+
                         |                               |
                         +--->(:TANGENT)--+--|angle|--+--+
                         |                |           |  |
                         |                +--|pos|----+  |
                         |                               |
                         +--->(:CLEAR_TANGENT)-------->--+
                         |                               |
                         +--->(:APPEND)--|open element|--+
                         |                               |
                         +--->(:ORDER)--|number|------>--+
                         |                               |
                         +--->(:BACK)----------------->--+

Options

The following options are available to create your B-spline.

:CLOSED - closes the B-spline creating tangency and curvature continuity at the first interpolation point. Curvature continuity is only achieved with an order of at least 3.
This option acts as a toggle with :OPEN.
:TANGENT - the specified interpolation point defines a tangent angle.
:APPEND - specifies a B-spline you want to append to another element. However, using :APPEND mutually excludes :CLOSED.
When the B-spline should be adjacent to existing elements, use :APPEND to specify the elements.
You can align either end of the B-spline with an existing element. The new B-spline has tangent continuity at the intersection point. You can select any type of open element, including another B-spline.
:ORDER - defines the control you have over the ultimate shape of your B-spline. The default B-spline order of 4 creates a curvature continuous curve that follows the interpolation polygon as closely as possible.
You can set a minimum order of between 3. There is no maximum value, however, a high order increases the performance, and decreases the possibility of wiggles between the interpolation points.
:BACK - deletes the last interpolation point specified.

The curve can be noncyclic or cyclic (having ends which meet smoothly). Tangent angle conditions may be specified at any interpolation point.

At each point you define, the "rubber band" facility displays the B-spline curve you are creating.

No two directly subsequent interpolation points may be coincident.

When to use

Use this action to create a B-spline anywhere in your active workplane.

When using this creation technique, OneSpace Designer automatically adds a series of interpolation points to the curve, as if you had defined them. You have no control over how many points are added, or where they are positioned. But, there is no difference between these points and user created interpolation points.

Note
It is dangerous to try to represent straight lines, rectangles, and/or circles (analytics), using B-spline interpolation points. OneSpace Designer will accept your points, and complete the operation. However, a body check performed at a later stage will report the body as corrupt.

Example

Enter BSPLINE_INT, and specify the interpolation points to define the B-spline.

BSPLINE_INT 100,100 100,73 75,73 35,27 COMPLETE