Rebuild Surface

Rebuild Type

• Rebuild – Change the degree (from 1 to 9) and the number of spans of the surface (along U or V independently) while maintaining the original distribution of spans and parameterization.
• Non-rational – Rebuild a rational surface as a non-rational surface (all CVs with equal weights).
• Reduce spans – Simplify the surface by removing extraneous edit points.
• Del multi-knots – Remove multi-knots from the surface.
• Uniform rebuild – Convert the surface to uniform parameterization.
• Match knots – Convert the surface to match the parameterization and degree of another surface.

Rebuild options

These options appear when Rebuild Type is Rebuild.

Rebuild Direction

• U and V – Rebuild the surface in both directions.
• V Only – Rebuild the surface in the V direction only. (Edges in the U direction are not affected.)
• U Only – Rebuild the surface in the U direction only (Edges in the V direction are not affected.)

Change Number of CVs

• On – Change the number of CVs (and hence of spans) in the rebuilt surface. Either a slider or two number fields appear(s) allowing you to set the number of spans in the U and/or V direction(s).
• Off – The number of CVs in the rebuilt surface is equal to the number of CVs in the original.

Change Surf. Degree

• On – Change the degree of the surface as it is rebuilt. Either a slider or two number fields appear(s) allowing you to set the degree of the rebuilt surface in the U and/or V direction(s).
• Off – Do not change the surface degree.

Non-rational options

This setting appears when Rebuild Type is Non-rational.

Tolerance

The maximum amount of deviation from the original surface permitted during the rebuild (in current linear units).

A low number matches the original more exactly, but does not simplify the surface as much. A high number does not match the original as well, but simplifies more.

Continuity Angle

The maximum angle allowed between the normals of the original and rebuilt surfaces. A smaller value matches the original more exactly, but usually requires the tool to add more spans to the surface.

Reduce spans options

This setting appears when Rebuild Type is Reduce spans.

Tolerance

The amount of deviation from the original surface permitted during the rebuild (in current linear units).

A low number matches the original more exactly, but does not simplify the surface as much. A high number does not match the original as well, but simplifies more.

Rebuild Direction

• U and V – Rebuild the surface in both directions.
• V Only – Rebuild the surface in the V direction only. (Edges in the U direction are not affected.)
• U Only – Rebuild the surface in the U direction only (Edges in the V direction are not affected.)

Del multi-knots options

This setting appears when Rebuild Type is Del multi-knots.

Rebuild Direction

• U and V – Rebuild the surface in both directions.
• V Only – Rebuild the surface in the V direction only. (Edges in the U direction are not affected.)
• U Only – Rebuild the surface in the U direction only (Edges in the V direction are not affected.)

Uniform rebuild options

These settings appear when Rebuild Type is Uniform rebuild.

Rebuild Direction

• U and V – Rebuild the surface in both directions.
• V Only – Rebuild the surface in the V direction only. (Edges in the U direction are not affected.)
• U Only – Rebuild the surface in the U direction only (Edges in the V direction are not affected.)

Change Number of CVs

• On – Change the number of CVs (and hence of spans) in the rebuilt surface. Either a slider or two number fields appear(s) allowing you to set the number of spans in the U and/or V direction(s).
• Off – The number of CVs in the rebuilt surface is equal to the number of CVs in the original.

Change Surf. Degree

• On – Change the degree of the surface as it is rebuilt. Either a slider or two number fields appear(s) allowing you to set the degree of the rebuilt surface in the U and/or V direction(s).
• Off – Do not change the surface degree.

Control Options

Keep Originals

Keep the original curve after creating the rebuilt curve.

Auto Update

Automatically update the new curve when the values in the Rebuild Curve window change.

MixMax Display

Automatically create and display min, mean and max locators between the original and rebuilt surfaces.

Max Deviation

Show the maximum deviation between the original and rebuilt surfaces on the prompt line, as well as the (U,V) location where it occurs.

Buttons

Update

When Auto Update is turned off, use this button to update the rebuilt curve with the current values.

Undo All

Undo all the changes made by the Rebuild curve tool and return to the original curve.

Next

Finish rebuilding the current curve and prompt for a new curve to rebuild.

Use this tool to remove multi-knots from a curve or surface, or rebuild a curve or surface so it has the same shape but fewer spans/patches.

Remove spans

1. Shift-select the tool icon: .
2. Set Rebuild Type to Reduce Spans and turn Auto Update on.
3. Click the curves or surfaces.

4. Click Go.

5. Use the Tolerance control to adjust how much the tool can simplify the curves.

   A low value creates a more exact copy but simplifies the curve less. A high value is less exact but simplifies more.

   Tip: If you click an isoparametric curve or trim edge with the Rebuild curve tool, it will be rebuilt into a curve on surface. You can only rebuild these curves as degree 1 or 3 curves.

Remove multi-knots

1. Shift-select the tool icon: .
2. In the Rebuild Type pop-up menu, choose Del Multi-Knots.
3. Click the curves or surfaces.
4. Click Go.

Convert rational to non-rational geometry

1. Shift-select the tool icon: .

2. Click the rational surfaces.

3. Click Go.

4. Use the Tolerance and Continuity Angle controls to adjust how close the new surface must come to the shape of the original.

   A low value creates a more exact copy but with more complex geometry. A high value is less exact but creates simpler geometry.