# Car Modeling Using Nurbs Part 4

## Intro

(Please read): In this part of the tutorial we are going to be working on the Rims of the car. By using these techniques, anyone should be able to make any type of rim. I chose this ring because of the clean cut, but it can be more advance if you desire to spend some extra time on it. The basics are the same. In case you want to use the same rim picture, just save the picture on step.

## 1: Image Reference

When starting to work on independent parts the first thing we should do is find our problem areas. Once we have found that out, we can start thinking about the right approach towards the making of our surface. For this surface I have pinpointed four issues that I we are going to face. Don't forget, there is only so much preplanning. It's acceptable if you find more issues as you advance.

a. The hole with the smooth rectangular shape
b. The triangular hole
c. The ring under the main surface
d. The L loft shape

Now that we have a list, we can start elaborating using same order

## 2: Making The Circles

Lets start by making two circles and scaling them to find the Y proportions of our tire. As you can see this is not the best reference picture, but it will get the job done as a guideline.

## 3: Draw Curve

Now using the CV curve, draw an upside down L and modify it is similar to shape 1, in step 1 .

## 4: Duplicate

Proceed to duplicate the curve and scale it on negative X, so is a perfect mirror of the original curve. After that you can attach the curves together.

## 5: Pivot

Make sure the pivot is at the center of the grid. If for some reason its not, you can change this by pressing the Insert key on your keyboard to make your pivot translation active and then grid snap to the center.

## 6: Draw Curve

Proceed to make another curve as an upside down V shape to match shape 2, in step 1.
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## 7: Cut Curve

Using the inner circle in shape 1, continue by cutting the curves. This way we know for sure, we have a perfect round shape all around the rim.

## 8: Cut Curve

Repeat step 7 with shape 2.

## 9: Results

As you can see this is giving us a nice round continuity on our rim.

## 10: Rebuild Curve

After cutting our curve you probably have some uneven CV curves so go ahead and rebuild the curve to something cleaner.

## 11: Attach Curves

Now lets attach the two curves together. Make sure there is a nice smooth transition between the two curves (make modification by hand if needed).

## 12: Close Curve

Go to edit curves- Open/Close curve to close the curve.

## 12: Close Curve

Repeat the last step with the curve next to it.

## 13: Duplicate Options

Open the duplicate options menu and change the options. The reason for these numbers is very simple. We need 8 triangular shapes and 8 squares shapes, but since we all ready created 2 we need to complete14 more. 360/8 = 45.

## 14: Results

Here we have it. Not bad, we can already see the shape of the rim coming together.

## 15: Duplicate

Select the curves, duplicate and scale to about 30% of the original size.

## 16: Offset

Now move the original curves about 0.5 units to the front and the second new scaled curves 3 units towards the back.

## 17: Arc Curve

Take a look at picture "a". Now draw a curve to follow this shape. Select the outcurve of the rim, duplicate and scale, as show on image/example "b".

## 18: Extrude

Select the two curves we just created and extrude to make this shape. Note: Something to have in mind, extrude is base on curve direction. If your extrude is upside-down just change the curve direction and that will fix it.

## 19: Curves

If we take a second look at our reference picture on step 1. We can see that we need to create an "L" shape. Go ahead and draw the L shape, then duplicate the outcurve and scale, as it is show on the picture.

a = The L shape
b = The half circle

## 20: Extrude

Select the two curves we just create and extrude to make this shape.

## 21: Loft

Go back to our original shapes and loft them together.

## 22: Results

After completing the 3 lofts your picture should look like this. Now that we have all the elements needed. We can move on to making our rims.

## 23: Duplicate

Select the two-mayor lofts and duplicate. Hide them into a layer; we will need them later.

## 24: Detach Surface

two isoparms as show and detach the surface. Note: All we are trying to accomplish is making our scene cleaner to work on.

## 26: Detach Surface

Select two isoparms as show and detach the surface.

## 28: Move Geometry

This is a side view of what we should have so far. In my case, I build everything on the center so I move my lower part back.

## 29: Circular Fillet

Referencing step 27 take shape "a" and "b" and circular fillet them together.

## 30: Circular Fillet

Now take Shape "a" and "c" and circular fillet them together.

## 32: Delete Geometry

We don't need shape "c" anymore. Go ahead and delete it.

## 33: Trim

Proceed to trim shape "a".

## 34: Detach Surface

There is a small problem here we will need to fix. We need to select an isoparm and detach surface.

## 36: Repeat

Bring back the two lofts surface we duplicated in step 23. Repeat the whole process from step 24 to 36 with the triangular shape.

## 37: Duplicate

Using the same attribute from step 13 we can go ahead and duplicate our two parts.

## 39: Planar

Select the outer curve and planar.

## 40: Rebuild Surface

After we have created the planar surface proceed to rebuild the surface in a way that you will have about 9 CV's to work with in the middle.

## 41: Select CV's

Select the 9 CV's in the middle of our plane.

## 42: Move CV's

Move the CV's back to create a dent in our plane.

## 43: Circular Fillet

Now go one by one and a circular fillet all 16 pieces.

## 45: Results

This is the result after trimming the plane and all 16 individual parts.

Using what we have learned up to now. Create some cylinder and modified them to make some trims and circular fillets.

By selecting one of the isoparms from the back of our ring, I extrude the isoparm to give some depth. Note: you don't have to complete this step since the tires will be covering this part. I just did it so you can get a feel for it.

A lot of us have been taught to model only what the camera sees but in some cases you have to model a little more to get a good sense of the model, even if you know ahead of time that its going to be deleted