V_Curve

Creates v-curve and v-surface on 3d polyline / 3D quadratic spline-fit polyline or a 3d mesh. Approximates a v-curve or a v-surface by b-spline of an even degree.

Command: v_curve

Options of command line

Parameters of the command depend on the selected object: a 3d polyline / 3D quadratic spline-fit polyline or a 3d mesh.

Select polyline: Select 3d polyline / 3d quadratic spline-fit polyline.

3D polyline / 3D quadratic spline-fit polyline

• Enter a creation option [Subdiv / Arrange / Degree / Create / Exit]: Enter an option.
• Enter an approximation option [Degree / Accuracy / Create / Exit]: Enter an option.

Subdiv (Subdivision)

Option defines the number of iterations of subdivision of segments of a v-curve. If the initial number of segments of a curve was N the resulting number will be N x (2 in a degree of an option Subdivision). The maximum value for Subdiv is 3. Enter new option Subdiv <current>: Enter an integer or press ENTER.

Arrange (Arrangement)

Option defines the mode of improvement of a curve. Value of an option 1 sets a mode of generation of points of a curve with redistribution of points on a contour of a curve with density to proportional curvature of a curve. Value of an option 0 sets a mode without redistribution of points. Enter new option Arrange <current>: Enter an integer or press ENTER.

Degree

• Option defines the even degree of an approximating b-spline in a range from 4 up to 10.
• Enter new option Degree <current>: Enter an integer or press ENTER.

Create
Creates v-curve in format of b-spline curve of an even degree.

3D mesh / 3D quadratic spline-fit on mesh

Enter a creation option [Subdiv / Degree / Create / Exit]: Enter an option.

Subdiv (Subdivision)

• Option defines the number of iterations of subdivision of segments of a v-curve. If the initial number of segments of a curve was N the resulting number will be N x (2 in a degree of an option Subdivision). The maximum value for Subdiv is 3.
• Enter new option Subdiv in direction U<current>: Enter an integer or press ENTER.
• Enter new option Subdiv in direction V<current>: Enter an integer or press ENTER.

Degree

Option defines the even degree of an approximating b-spline in a range from 4 up to 10.

Enter new option Degree in direction U <current>: Enter an integer or press ENTER.
Enter new option Degree in direction V <current>: Enter an integer or press ENTER.

Create
Creates v-surface v-curve in format of b-spline surface of an even degrees.

Restrictions on the form of 3d-polylines and on the form of rows and columns of a 3d-mesh

1). There should not be conterminous points; 2). The corner between parts of a polyline should be more than 90 degrees. 3). Rectilinear sites of a curve should be specified by three (or more) points on a direct line.

Recommendations

At approximation v-curve / v-surfaces by b-splines of high degrees (a degree of a spline 6, 8, 10) use a small degree of condensation v-curve / v-surfaces. It is recommended to set parameter Subdiv = 1.

The connected system variables
DelObj: whether specifies it is possible to delete initial object.