EVANJAMESLONG

Production Pipeline for creating a 3D Chevrolet Chevelle SS

By Evan Long

1. Pre-production

Although not a motor enthusiast, I am drawn to the American muscle cars of the 70’s and 80’s and have decided to model a Chevrolet Chevelle SS. I have found a range of images that I think will be helpful  in the production process. These images will give me information about form, colour and the details to be included in the modelling and texturing process.

Figures1-8: Images of the SS Chevelle to be used as references. The frontal, rear and orthographic views will be imported as image planes.

2. 3D Modelling

Before importing the images as reference planes, I need to adjust the image dimensions so they are all in alignment with each other. Photoshop rulers are  used to line up key visual identifiers on each view of the car.

Once I’ve imported the reference images into the front and side viewports in Maya, starting with a polygon cube, I will begin to shape out the body of the car using the side viewport as my main reference point.

Figure 9: Orthographic view of the SS Chevelle.

Figure 10: Perspective view of the blocked out body.

The following screenshots demonstrate the development of the model. I applied some texture shaders early on to help give me an idea of how the final model would look.

As the images demonstrate, I modelled half of the car to save time. Once happy with the shape, I used the duplicate special function to complete the model. All smaller details of the model were modelled by eye. I didn’t have orthographic views of the individual components that make up the car, so I had to work by eye or use pixelated images, which wasn’t ideal.

Figures 11-14: Stages in the modelling process.

Once the shape of the car was finalised, I spent some time refining the model by using the bevel tool to define edges. I extracted the doors, windows and bonnet for further adjustments. The wheels and headlights and other smaller details were modelled separately.

3. UV Mapping

Although I will be using some Mental Ray metallic paint shaders for the body of the car, I still need to perform a fair amount of UV unwrapping.

This includes creating UV maps for the boot, bonnet, the tyres, the car seats, the headlights, the steering wheel and the number plate. The following images demonstrate this process.

Figures 15-20: UV maps created using the UV editor and planar mapping function.

4. Texturing and Shaders

For the body of the car I will be creating a new shader within the Mental Ray plugin. This plugin has a metallic car paint preset which I will be starting from.The default setting requires some tweaking before committing to the shader. In particular, I found the reflected colour to be too bright, so turning this value down improved the appearance of the model. With some tweaking of the specularity and and reflectivity, I found a result i’m happy with for the body.

The UV maps I created earlier are then imported into Photoshop to develop further texture information for the model.

Here are some examples of the textures created in Photoshop.

Figures 21-24: Texture maps created in Photoshop

The seat and tyre UV textures were re-used as bump maps to add further detail to the model.

Figure 25: The final textured model

5. Rigging

I have decided to have the model drive into position for the initiation of turntable and then drive off when the turntable animation completes.To do this I have rigged the wheels using the expression editor. Following a tutorial, I used the measure tool to determine the radius of the wheels and then performed some calculations using 2 pi r to come up with rotational data that would allow the wheels to move in relation to the speed of the body of the car.I first combined the mesh components of the body and the wheels separately and then used the centre pivot tool on all objects.

0.864795 = radius

5.4309126

66.29834254143646

The following commands were then scripted into the Expressions editor by selecting the outliner objects and applying the data to each wheel and the car body.

FL_wheel.rotateX = Car_Combined_Body.translateZ*66.30;

FR_wheel.rotateX = Car_Combined_Body.translateZ*66.30;

RL_wheel.rotateX = Car_Combined_Body.translateZ*66.30;

RR_wheel.rotateX = Car_Combined_Body.translateZ*66.30;

Once the expression is named, I then parent the wheels with the car body by selecting the wheels and then body and going to /edit/parent.

This now allows me to move the car back and forth and have the wheels rotate in relation to the movement of the car body.

6. Animation

This model will be animated firstly by applying a turntable animation. This can be done by finding a suitable perspective view and then applying the Turntable animation in the animation editors.

I set my turntable to continue for 350 frames as i felt it was too fast with less frames.

I’ve also animated the wheels to turn and the driver’s door to open to demonstrate some functionality of the model.

7. Lighting

I’ve used 4 lights to light the model in my scene as well as creating and endless horizon to ensure the light is reflected evenly across the model as the camera rotates around it.

3 spot lights were used, with the intensity value turned down significantly. One light was placed each side of the model and a spotlight was placed at the rear of the model. The fall-off value of the spotlight was increased to create a softer shadow.

The shadow information was also adjusted by increasing the shadow rays to give a softer and more realistic shadow effect.

So here is the final model.