Maya Rendering Guides

Creating the Wheel Covers

We'll be conducting some more patch work to create the wheel covers that attach to the body at the front wheels. Patch modeling is a way to create surfaces that need to attach to each other seamlessly. Although patch modeling is a fairly involved and advanced topic, having a little bit of an introduction to patching is a good idea. You will have another chance to patch model later in this chapter. For now, we will patch model the wheel covers at the front of the rocket, as shown in Figure 5.98, and create them to be seamless.

Figure 5.98 The wheel cover

Creating a Curve on Surface

You can load the scene file RocketModel_08.ma from the Scenes folder in the Red Rocket project to continue from this point or to check your work from the previous section.

1. Move the wheels up 0.381 units in the T-axis to get them up just a little bit closer to the body, as in Figure 5.99. Move the axles accordingly.
2. Select the bodyGeom surface and make it Live by pressing the Make The Selected Object Live icon ( O )■ This will enable you to create a curve directly on the surface of the rocket body. This curve, called a curve on surface, lies entirely on the surface of the body and cannot be pulled off. As such, it conforms perfectly to the contours of the surface, making the curve perfect for creating smooth patches for the wheel cover.

Figure 5.99 Move the wheels up closer to the body

Making an object Live in Maya allows you to create certain objects, such as curves, directly on their surface. Once you make an object live, its wireframe will turn a medium shade of green.

3. Select the CV Curve tool (Create * CV Curve Tool) and begin drawing an arc around the top of the front left, as shown in Figure 5.100. Start at the lower left and work clockwise to the lower right. Press Enter when you have laid down the last CV to create the curve on surface. Figure 5.101 shows a different angle of how the curve sits on the surface.

Figure 5.100 Draw a curve on surface to outline where the wheel cover meets the rocket body.

Figure 5.101 The curve on surface as shown from a different angle

1. Click the Make The Selected Object Live icon ( O ) icon again to deactivate the rocket body geometry.
2. You can adjust the CVs of the curve on the surface as you would adjust any other curve to smooth the arc. The CVs, however, are just confined to move across the surface of the rocket body and may not be pulled off. When you select one of the CVs, or the curve itself, and enter the Move tool, the cursor changes from the normal Move manipulator, as shown in Figure 5.102.

Figure 5.102

Lofting the First Shape

Now we can begin creating the surface of the wheel cover.

1. Select the curve on surface, and choose Edit Curves * Duplicate Surface Curves to create a copy of this curve. Center the pivot of the curve.
2. Move the curve out in the X-axis to be above and in front of the wheel. Adjust the curve to flatten it out parallel to the wheel, as shown in Figure 5.103. The curve on surface and this duplicated flattened curve will serve as our loft curves for the wheel cover.
3. Loft between the curve on surface and this new flattened curve. This will leave you with a straight surface between the two curves. Insert two isoparms lengthwise on the lofted surface, as shown in Figure 5.104.
4. Right-click the new lofted surface and select Hull from the marking menu. Select the second to last hull, closest to the body. Move the hull closer to the body and slightly down to create a smooth arc from the body to the wheel cover, as shown in Figure 5.105. Move CVs on the curve on surface as well as on the new lofted surface to finesse the transition from the surface of the body to the surface of the wheel cover.

Figure 5.103 Figure 5.104

Move out the curve and flatten it to the plane of the Insert two isoparms to add detail.

wheel.

Figure 5.103 Figure 5.104

Move out the curve and flatten it to the plane of the Insert two isoparms to add detail.

wheel.

Figure 5.105 Move the hull and adjust the CVs to create a smooth blend between the body and the wheel well.

Manually Editing the Wheel Cover Surface

Now you will need to put in some elbow grease to mold the wheel well into a perfect shape. The more time you spend on it, the nicer it will come out. Conversely, if you are interested in just the nuts and bolts of modeling, you can put in a minimum amount of time to just make it work. It's up to you. If you've done steps 1 through 9 in the preceding section, continue here.

Manually move the CVs and some hulls around to shape the wheel cover so it approximates the shape shown in Figure 5.106. In this image, CVs on both the original curves of the loft as well as CVs and hulls of the loft surface itself were sculpted to attain the shape you see here. In essence, the following needs to be done:

• The seam where the wheel cover meets the rocket body must be further sculpted to make it larger than the previous steps. This will also make it smoother.
• The outer lip of the wheel cover needs to be bent down (as shown in a few of the angles in Figure 5.106) by scaling the outer lengthwise hull downward and adjusting the other hulls lengthwise up to create an arc over the tire.
• The CVs on the ends of the wheel cover need to be moved out to give the tire more space inside the cover, and then adjusted to maintain a straight edge.

Figure 5.105 Move the hull and adjust the CVs to create a smooth blend between the body and the wheel well.

Figure 5.106 Several angles of the wheel well show you the shape you should aspire to in your modeling.

You can import the file wheelCoverSample.ma from the Scene folder of the Red Rocket project into your scene to skip creating this object, to use it as a template on which to build your own, or simply to check your work.

Figure 5.107 shows the original lofted shape up to this point of the exercise as it compares to the final shape of the wheel well shown in the light wireframe.

Figure 5.107 The light wireframe shape shows the intended shape of the wheel well compared to the solid surface you should have by this point of this exercise.

Figure 5.108 First, select the isoparms, and then detach the surfaces.

Front Wheel Cover

Once you have a satisfactory wheel well shape, as shown in Figure 5.106, you will need to cap the open end to cover the top half of the hubcap, as in the real rocket shown in Figure 5.98 earlier in the chapter. We can accomplish this with a simple loft with the following steps:

1. Because a loft requires more than one curve or isoparm to work, we need to break the single wheel well surface so that we can loft between them. We will create 3 surfaces out of this surface. Select two isoparms as shown in Figure 5.108 (left) and choose Edit NURBS * Detach Surfaces to break the wheel cover surface into three surfaces as shown in Figure 5.108 (right). The middle surface is deselected (does not have a wireframe visible on the shaded surface) in Figure 5.108 (right) to show the distinction among the three surfaces.

Select these two isoparms.

Surface 1

Surface 2

Surface 3

Select these two isoparms.

Surface 1

Surface 2

Surface 3

Figure 5.108 First, select the isoparms, and then detach the surfaces.

Figure 5.109 First, loft between the side surfaces in step 2 (left), and then stitch the loft surface to the wheel cover in step 4.

2. Now we will loft between the side surfaces (Surface 1 and Surface 3 in Figure 5.108). Select the edge isoparm of Surface 1, Shift+click the edge isoparm for Surface 3, and choose Surfaces * Loft □. In the Option box, set the Section Spans to 4. Click Loft to create the loft shown in Figure 5.109 (left). You will want as many Section Spans for this loft as you have spans in Surface 2 (in this case, 4). This will make it easier to stitch the front wheel cover to the three surfaces.

Figure 5.109 First, loft between the side surfaces in step 2 (left), and then stitch the loft surface to the wheel cover in step 4.

1. Now let's stitch the front cover to the wheel cover surfaces. Deselect any surfaces. Choose Edit NURBS * Stitch * Stitch Edges Tool, and your cursor will turn into an arrow.
2. With the Tool cursor, select the edge isoparm of the Surface 2 surface, and then select the edge isoparm of the front cover loft you just created. Press Enter to complete the tool. The front cover should stitch to the three surfaces perfectly, as shown in Figure 5.109 (right).
3. Select all the surfaces and delete their history (Edit * Delete by Type * History). Group them together and call the top node wheelCover.
4. Duplicate the wheelCover node, scale it to -1 in the X-axis, and place it over the right side front wheel. Save your work!

You can load the scene file RocketModel_09.ma from the Scenes folder in the Red Rocket project to check your work on the wheel cover.

Whoa! That was a lot of work, but in the end, it was fun and you got a great model out of it.

+1 0

Average user rating: 5 stars out of 1 votes