Create Surfaces from Curves

A common way of working in 3-D is to draw curves that represent edges, profiles, cross-sections, or other surface features and then to use surfacing commands to create surfaces from those curves.

Edge curves

You can create a surface from three or four curves that form the sides of the surface.

EdgeSrf command iconCreate a surface from edge curves

1. Open the tutorial model EdgeSrf.3dm.
2. On the Surface menu, click Edge Curves.

Review the help topic for the EdgeSrf command.

3. Select the four curves.

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Objects change to yellow when you select them.

A surface is created from the curves that form its edges.

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Extrude curves

Extruding creates surfaces by tracing the path of a curve in a straight line.

ExtrudeCrv command iconCreate an extruded surface

1. Open the tutorial model Extrude.3dm.
2. On the Surface menu, click Extrude Curve, and then click Straight.

Review the help topic for the ExtrudeCrv command.

3. Select the curve (1).

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4. At the Extrusion distance prompt, drag a distance with your mouse and click.

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Loft curves

Lofting creates a smooth surface that blends between selected shape curves. This surface looks similar to the Sweep a curve with two rails example, but is created without rail curves. Instead, the edges of the surface are created by fitting smooth curves through the shape curves.

Loft command iconCreate a lofted surface

1. Open the tutorial model Loft.3dm.
2. On the Surface menu, click Loft.

Review the help topic for the Loft command.

3. Select the three curves (1), (2), and (3), and press Enter.

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4. In the Loft Options dialog box, click OK.

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5. Try some of the Style options and then click Preview to see the various loft styles.

Revolve curves

Revolving a curve creates a surface by revolving a profile curve about an axis. This is sometimes called lathing.

Revolve command iconCreate a revolved surface

1. Open the tutorial model Revolve.3dm.
2. In the status bar, click Osnap.
3. In the Osnap panel, click End.
4. On the Surface menu, click Revolve.

Review the help topic for the Revolve command.

5. Select the profile curve (1) and press Enter.

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6. At the Start of revolve axis prompt, snap to one end of the axis line (2).

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7. At the End of revolve axis prompt, snap to the other end of the axis line (3).

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8. At the Start angle... prompt, select the FullCircle option.

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Revolve curves with a rail

Rail revolve creates a surface by revolving a profile curve around an axis while at the same time following a rail curve. This is basically the same as Sweep Along 2 Rails, except one of the rails is a central point.

RailRevolve command iconCreate a revolved surface with a rail curve

1. Open the tutorial model RailRev.3dm.
2. On the Surface menu, click Rail Revolve.

Review the help topic for the RailRevolve command.

3. Select the profile curve (1).

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4. At the Select rail curve... prompt, select the rail curve the revolve will follow (2).

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5. At the Start of RailRevolve axis prompt, snap to an endpoint of the axis line (3).

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6. At the End of RailRevolve axis prompt, snap to the other end of the axis line (4).

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Sweep along one rail curve

Sweeping creates a surface with cross sections that maintain the initial orientation of the shape curve(s) to the path curve.

Sweep1 command iconCreate a sweep surface

1. Open the tutorial model Sweep1.3dm.
2. On the Surface menu, click Sweep 1 Rail.

Review the help topic for the Sweep1 command.

3. Select the rail curve (1).

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4. At the Select cross section curves ... prompt, select the cross-section curve (2), and press Enter.

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5. In the Sweep 1 Rail Options dialog box, click OK.

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Sweep along two rail curves

Using two rails for a sweep creates a smooth surface through two or more shape curves that follow two curve rails. The rails also affect the overall shape of the surface. Use this command when you want to control the location of the edges of the surface.

Sweep2 command iconCreate a sweep surface with two rail curves

1. Open the tutorial model Sweep2.3dm.
2. On the Surface menu, click Sweep 2 Rail.

Review the help topic for the Sweep2 command.

3. Select the first rail curve (1).
4. At the Select second rail... prompt, select the second rail curve (2).

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5. At the Select cross section curves prompt, select the two cross-section curves (3) and (4), and press Enter.

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6. In the Sweep 2 Rails Options dialog box, click OK.

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