Extruding a Spline to Create an Object
Author: 2007-06-22 22:33:55 From:
Tips & Techniques - Modeling
Modeling:
Using Extrude NURBS to Create Objects
| Download:
PDF / | Works with:
XL | Requires:
Version 6+ |
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| | | Extrusion creates a solid object by pushing a spline or 2D profile along the axis perpendicular to the surface of the shape. It is just like the old playdough factory - - choose a shape and push the clay through the hole. Common models created with an Extrusion include gears, flying text and logos, etc. This tutorial will take you through the process of using Extrude NURBS in XL 6. |  |
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| |  | Step 1: First off, we need to create a spline to work with. Since extrudes are commonly used with flying text, we'll use a text spline. Create a text spline (Objects=>Spline Primitive=>Text). |
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| | | Step 2: Open the Text Spline's attributes by double clicking on the icon in the Object Manager. Replace 'Text' by typing 'CINEMA' in the text box. Leave all of the current settings and click OK. The spline will instantaneously change to the new text. |  |
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| |  | Step 3: Now, create an Extrude NURBS object (Objects=>NURBS=>Extrude NURBS). |
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| | | Step 4: Drag and drop the Text Spline into the Extrude NURBS object. You'll notice that in the editor window, the spline has now become 'extruded' or three dimensional. |  |
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| |  | Step 5: The object should now look similar to this. |
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| | | You can further modify the way the Extrude NURBS operates and appears. Double click on the Extrude NURBS icon in the Object Manager. Under the General tab, you'll notice that there are a few options. Isoparm Subdivision defines the number of isoparms used when viewing your scene in the Isoparms mode. The X/Y/Z movement field define the extrude distance on the particular axis. The Subdivision field allows you to determine the subdivision in the extrude. The Start/Stop popup menus allow you to choose what kind of 'capping' you would like on your extrude. Flip Normals reverses the direction of the normals. CINEMA usually points the normal the correct direction, however open contours are not easily calculated by CINEMA. In that case, use the Flip Normals option. |  |
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| |  | Under the Details tab, you can further modify the Extrude NURBS. These options allow you to change the way caps of the extrude appear. The Rounding popup menu allows you to select between several different types of rounding. Hull and Hole inwards are options that make the rounding either round inward or outward. Constrain Contour determines whether the object is preserved or if it is 'inflated' by the rounding. Regular Subdivision allows you to build the extrude from quadrangles instead of triangles. This can reduce the amount of artifacts you might experience when using Extrude NURBS. |
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| | | Using the Heirarchical checkbox... |
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| | | The Hierarchical checkbox is an option that allows an Extrude NURBS to effect multiple splines within its hierarchy. |
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| | | Step 1: Using the Extrude NURBS object from earlier, open the attributes for the Text Spline by double clicking on the icon in the Object Manager. Check the 'Create Separate Letters (Make Editable)' box. Click OK. |  |
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| |  | Step 2: Make the Text Spline editable (Structure=>Make Editable). You'll notice that the extrude in the Editor Window will disappear. This is because there is now an object group in the Extrude NURBS instead of a spline. |
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| | | Step 3: To remedy this, all you have to do is open the attributes for the Extrude NURBS object and check the Hierarchical box. Click OK. The extruded text should reappear in the Editor Window. |  |
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| | | Using two or more splines... |
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| | | Creating 'Hole Splines' by using multiple splines is fairly easy to do and can create some interesting effects. |
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| |  | Step 1: Create a Rectangle Spline (Objects=>Spline Primitive=>Rectangle). |
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| | | Step 2: Create a Flower Spline (Objects=>Spline Primative=>Flower). |  |
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| | | Step 3: Make both splines Editable (Structure=>Make Editable). |
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| |  | Step 4: Now we'll group the splines together (Objects=>Group Objects). Once the cursor has become a cross-hair, drag a marquee over the two objects to group them. |
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| | | Step 5: We now have to make them one spline. Select the Object Group and run the Connect function (Functions=>Connect). A new spline will appear in the Object Manager.This will be the spline that we will use with the Extrude NURBS. |  |
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| |  | Step 6: Create an Extrude NURBS object (Objects=>NURBS=>Extrude NURBS). Drag and drop the new spline into the Extrude NURBS. The spline will then become extruded. |
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