Modeling a Tire
The first thing to do is to get hold of good reference material; such can easily be obtained by searching Google or any of the manufacturer’s WebPages. Once settle on what type of tread pattern to create, either load it as a Rotoscope image in XSI or use it as it is.
Start by creating a Grid and lower the Y Length to 1.5. Increase the U Subdivisions to 19 or so and the V to 2. Select the middle V edge row and, in the top viewport, move it downwards so its just above the end of the grid. Move each of the U edge rows to form the proper gaps between the treads (additional screenshots can be found on the cover CD). Next move the polygons so you get sort of a V-shaped pattern. Select all the polygons that are to form the height of the tread, press [CTRL + D] to duplicate them and move them slightly upwards. With the polygons still selected, from the Modify>Poly.Mesh menu choose Bevel Components.
With the first section completed it’s time to create the remaining part of the tire. With your object selected, press [CTRL + Shift + D] to open the Duplicate Multiple PPG. Enter 45 as number of Copies and switch to the Transform tab. In the Z Translation box, enter 1.5 and click OK. Select all objects and from the Create>Poly.Mesh menu choose Merge. Lower the Tolerance to about 0.1 and click the Delete button in the PPG to freeze the new object. In the Transform Panel, click Transform>Move Center to Bounding Box before applying a Modify>Deform>Bend operator. In the PPG, change the Axis to Z and set the Angle to about -382. Change the Radius to about 11 and set the Z Offset to -37. To weld the seam together choose Modify>Poly.Mesh>Boundary Points/Edges. Hold down the [Alt] button and click with the middle mouse button on one of the edges at the very end at each side of the tire (hold down [Shift] as well to add to the selection) to select the entire row/loop. Duplicate the edges and scale them down a couple of times to form the side of the tire.
The project files used in this tutorial can be found at:
By focusing on a single section of the tread pattern you can allow more attention to go in to details; a technique that works for just about any type of tire.