Creating a Revolved Rail Surface
Tutorial provided by Nemetschek North America
December 16, 2003
This VectorWorks tutorial covers the basics of revolving a NURBS curve around an axis point by creating a 3D tent.
Setting Up the Modeling Units
This tutorial works in inches.
To set up the units for modeling distances in inches:
1. Select Page > Units.
2. In the Units dialog box, select Inches from the Unit Name list.
All distances entered for designs will now be in inches.
Creating the Base
The Reg Polygon Settings dialog box opens.
3. Enter 5 for the Number of Sides, and then click OK.
4. Click on the 3D locus point and drag the cursor vertically upward. Press the Tab key to highlight the L field in the Data Display bar. Enter 2″ and press Enter (Win) or Return (Mac) to set the length. Click to set the size of the polygon.
5. With the polygon still selected, select Model > Convert to NURBS.
Creating the Axis
1. Select View > Standard Views > Right Isometric.
3. Clicking on the 3D locus point as the start point, move vertically upward until the I field in the Data Display bar reads -5″. Double-click to set the NURBS curve.
4. With the NURBS curve still selected, select Vertex Only from the Move list in the Object Info palette.
5. Click the right Edit arrow to highlight the top vertex of the NURBS curve.
6. Change the plane of the vertex to be perpendicular to the plane of the polygon. Change the Z value to 5″. Change the X and Y values to 0″.
Creating the Profile Curve
2. Click on the 3D locus, the top of the axis, and then one of the corners of the base to set the working plane.
click on image to enlarge
4. Click the NURBS Curve tool from the 3D Tools palette, and then select NURBS Curve By Interpolation Points from the Mode bar.
5. Click on the top vertex of the axis line, and then double-click on the corner point of the polygon that was selected to create the working plane.
A linear NURBS curve is created.
6. With the NURBS curve still selected, enter 2 in the Degree field of the Object Info palette.
7. Click the right Edit arrow to highlight the newly-created center vertex point, and then change the X value to 0, the Y value to 1/4, and the Zvalue to 1.
Revolving Around a Rail
1. Select Model > Revolve with Rail.
2. Click on the axis line, the profile curve, and then the base polygon.
3. The profile curve is revolved around the axis line, creating a grouped series of NURBS surfaces.
Editing a NURBS Surface
1. With the new group still highlighted, select Organize > Ungroup.
2. Click on an unused area of the screen to deselect all objects. Select one of the 3D NURBS surfaces.
3. In the Object Info palette, change the V Degree value to 2.
5. Click on the bottom center vertex and pull upward to create an opening in the tent. When the Z value in the Data Display bar reads 2.750″, click to set the change.
The tent is complete.