Rebuild

Toolbar Menu

Curve Tools

Surface Tools

Edit

Rebuild

 History enabled

The Rebuild command reconstructs selected curves or surfaces to a specified degree and control point number.

Steps

  • Select the curves or surfaces.

    Or, press Ctrl (CMD) + Shift to select a polycurve segment.

Curves and extrusion objects

To rebuild curves

  1. Click Preview to see what the rebuilt curves will look like.
  2. When you are satisfied with the results, click OK.

Note

  • Turn on control points and curvature graph to see the details of the curve structure.
  • A group of curves will be rebuilt with curves of a specified degree and specified number of control points. The knot of the resulting curve more evenly spaced. To rebuild a curve with uneven knot spacing but a more accurate fit, use the FitCrv command.

Rebuild options

Point count

Reports in parentheses the current number and sets the number of control points in the result.

Degree

Reports in parentheses the current number and sets the degree of the curve. Degree in Rhino can be up to 11.

Point count and Degree values change automatically to fulfill the minimum requirement of Point count = Degree + 1. For example, when Point count=4 and Degree=3, reducing Point count also reduces Degree; increasing Degree also increases Point count. In closed curves/surfaces, the start and end points are overlapped and counted as one. They have one less point than open curves/surfaces.

Delete Input

Deletes the original geometry.

 History enabled

History is supported when Delete Input is unchecked.

Create new object on current layer

Creates the new objects on the current layer. Clear this check box to place the new objects on the layer of the original curves.

Preserve end tangent directions

The new curve matches the input curve end tangents if the curve is open, the degree is two or more, and the point count is four or more.

Make SubD friendly

Makes the output curve compatible with SubD. Details...

When this option is enabled, the Degree option is disabled. The output curve can only be degree 3.

Select Master Curve

Rebuild a curve to match another curve's parameter structure. The SubD friendly state of the master curve will be ignored.

The Loft, Sweep1 and Sweep2 commands create a better surface from section curves with the same parameter structure.

Span counts

Reports in parentheses the minimum number of spans and the proposed number of spans.

Maximum deviation

Reports the maximum deviation from the original curve when Preview is clicked.

Preview

Displays a preview of the output.

If you change the settings, click the Preview button again to refresh the display.

To access hidden command-line options

  • Type a hyphen in front of the command name: -Rebuild.
Command-line options

SubCrv

Type subcrv to select part of a curve as input.

Surfaces

To rebuild surfaces

  1. Click Preview to see what the rebuilt surfaces will look like.
  2. When you are satisfied with the results, click OK.

Rebuild Surface Options

Point count

U

Reports in parentheses the current number and sets the number of points in the u direction.

V

Reports in parentheses the current number and sets the number of points in the v direction.

Degree

U

Reports in parentheses the current number and sets the degree in the u direction.

V

Reports in parentheses the current number and sets the degree in the v direction.

Point count and Degree values change automatically to fulfill the minimum requirement of Point count = Degree + 1. For example, when Point count=4 and Degree=3, reducing Point count also reduces Degree; increasing Degree also increases Point count. In closed curves/surfaces, the start and end points are overlapped and counted as one. They have one less point than open curves/surfaces.

Options

DeleteInput

Deletes the original geometry.

Current Layer

Creates the new surfaces on the current layer. Clear this checkbox to place the new surfaces on the layer of the original surfaces.

Retrim

Trims the rebuilt surface with the original trimming curves.

Span counts

U

Reports in parentheses the minimum number of spans and the proposed number of spans in the u direction.

V

Reports in parentheses the minimum number of spans and the proposed number of spans in the v direction.

Maximum deviation

Reports the maximum deviation from the original surface.

Calculate

The calculation tests how far away the new surface is at knot line intersections and half-way between knot lines. Conducts tests at knot line intersections and halfway between knot lines.

The display color indicates how far away the new surface is from the original. Points are green if the surface is within absolute tolerance, yellow if it is between tolerance and 10 times tolerance, and red if it is farther away than that.

Preview

Displays a preview of the output.

If you change the settings, click the Preview button again to refresh the display.

RebuildUV

Toolbar Menu

Surface Tools

Not on menus.

The RebuildUV command reconstructs selected surfaces to degree 3, with a specified control point number, in either the u or v direction. The surface structure in the other direction is left unchanged.

Steps

  • Select surfaces to rebuild.
Command-line options

Direction
(Surfaces only)

Specify the u, v, or both directions.

PointCount

Specifies the number of control points in the result.

Type

Loose

The surface control points are created at the same locations as the control points of the original. This is a good option if the control points will be edited later.

Normal

The surface has an average amount of stretching between the curves. This is a good choice when the curves are proceeding in a relatively straight path or there is a lot of space between the curves.

Straight sections

Creates a ruled surface. The sections between the curves are straight.

Tight

The surface closely follows the original. This is a good choice when the input curves are going around a corner.

Uniform

Makes the object knot vectors uniform.

DeleteInput

Yes

Deletes the original geometry.

No

Retains the original geometry.

CurrentLayer

The output will be on the current layer.

ReTrim

Trims the rebuilt surface with the original trimming curves.

RebuildCrvNonUniform

Toolbar Menu

Curve Tools

Not on menus.

The RebuildCrvNonUniform command interactively modifies selected curves by non-uniformly re-spacing the control points.

Steps

  1. Select the curves.
  2. Drag the points on the curves.
  3. Click the direction arrows to reverse the curve direction.
Command-line options

RequestedTolerance

Specifies the maximum distance the rebuilt curves can deviate from the originals. If you do not provide enough control points, the rebuilt curves may deviate more than RequestedTolerance from the originals.

The maximum deviation from the original curves is reported at the command line and marked with a point on the curve.

MaxPointCount

Specifies the maximum number of control points per curve used to rebuild.

Quarters

Displays two more controls along each curve to influence how the RebuildCrvNonUniform command distributes control points. The controls at the end of the curves can be used to shorten the resulting curves.

DeleteInput

Yes

Deletes the original geometry.

No

Retains the original geometry.

ResetPoints

Resets the editing points to their original locations.

SubCrv

Type subcrv to select part of a curve as input.

Elmo

Toolbar

Menu

Not on toolbars.

The Elmo command rebuilds curves with more customizable options.

The polycurve is rebuilt with fewer control points and its kinks preserved.

Command-line options

PointCount

Number of control points in the rebuilt curve.

VariablePointCount

Rebuilds curves with various number of control points that produces the smallest separation..

Minimum/Maximum

The lowest/highest number of control points allowed for the rebuilt curve.

Degree (1~11)

Degree of the rebuilt curve.

TangentMatch (No/Start/End/Both)

Controls whether the tangent direction at the start, end, or both ends of the input curve is maintained. Choose No to ignore the tangent direction at both ends.

SubDFriendly

Makes the resulting curve compatible with SubD.

Smoothing (None/Low/Medium/High/Custom)

Controls the smoothness of the resulting curve.

  • The smoothing value can be set to 0 (None), 0.01 (Low), 0.1 (Medium), 1 (High), or a custom value between 0 and 10.

  • Higher values result in greater deviation from the input curve.

Uniformity (None/Low/Medium/High/Custom)

Controls how evenly the control points are spaced along the rebuilt curve.

  • The Uniformity value can be set to 0 (None), 0.01 (Low), 0.1 (Medium), 1 (High), or a custom value between 0 and 10.

  • Higher values result in more even spacing between control points.

KinkSplit

Controls whether to split the kinks of polycurves. This option is only available for polycurves or curves with discontinuous curvature.

KinkAngle

The minimum angle (in degrees) between adjacent curve segments to be considered a kink. Curve segments that exceed this angle are split at the kink.

SplitAtCurvatureChanges

Splits curves at locations where the curvature are not continuous, even if they are not sharp kinks

The degree-2 curve's curvature graph is discontinuous at two locations.

See Also

Rebuild

Reconstruct curves, surfaces, and extrusion objects to a specified degree and control point number.