WAYNE WESTERMAN
PHOTOSHOP RENDERING

Wayne Westerman is a professional designer working at the GM advanced design studio in Sweden. This tutorial gives a step by step guide to his digital rendering technique; further tutorials and articles by Wayne can be viewed at the following links:-
CarDesignNews Tutorial
Telegraph Article

Create and Scan Your linework.
I usually sketch on A3 or A4 layout paper with a black Biro. Don’t be afraid to use as many underlay as you need to get the sketch right, even professionals don’t get it right first time every time. A useful technique to help correct any perspective problems is to flip the drawing over and work on the reverse side of the paper. This will highlight any problems with your perspective. When you are satisfied with the design theme scan the drawing at 200/300dpi, this resolution will give good quality images when printed.

Paths in Photoshop appear as black lines, therefore changing the colour of the scanned linework with hue and saturation will make the paths more visible. Also choose a colour which will be visible over the colour you intend to render the car. Finally convert the linework layer to multiply mode. All subsequent layers will be placed underneath this layer allowing you to see both the linework and the rendering as it progresses.

To achieve a very quick impression of volume and proportion create 3 more layers. On the bottom layer (one above background) create a path which follows Y-zero (industry term for the cars centreline along it longitudinal axis) Convert the path to a selection and fill with a gradient, getting darker towards ground level. On the second layer create a path which outlines the wheelarch openings, tyres and shadow cast by the car, fill with black.
And on the third layer create paths which outline the DLO, (daylight opening, industry term for the glass graphics) one for the boot glass and one for side glass and screen (this car has no visible A-pillar). Fill with a dark hue.

Import the wheels. Use either a photographic image or in this case an existing Photoshop rendering. Size and position the wheels so the light is falling in the correct direction. Create a layer between the wheels and the wheelarch/shadow layer. Create a circular selection and using the airbrush tool add a lighter tone to create the top of the tyre. Deselect and add Gaussian blur.

Continue to block in volumes. Here the sill, grill, headlamp, taillamp and rear panel have been added with some tonal graduation to give more depth. Again paths were used to trace over the original linework layer and each element rendered on it’s own individual layer.

Adding More Depth to the bodyside
Duplicate the graduated bodyside layer. Using the linework layer as reference, create a path defining an imaginary horizon line and add points to close the path around the lower part of the body. Convert the path to a selection, invert the selection and delete everything outside. Make this layer slightly darker, lock the transparency and using different sized brushes stroke darker and lighter tones across the layer to create a stylised horizon on the bodyside.
For a really polished finish you could reflect the surrounding floor, gravel, grass paving stones etc. Unlock the transparency and apply Gaussian blur to soften.
Create a new layer and make the Y-zero path visible and convert to a selection with a soft edge brush apply dark tones to create the shoulder of the car.
To create more contrast create a layer beneath the previous two but above the original bodyside layer and apply white with a soft brush. Play with the opacity levels as you apply the white, delete and reapply until you achieve the desired effect. Remember this is on a separate layer so you can adjust the layer opacity at a later stage if you wish.

Creating the Glass and Interior. Reduce the opacity of the DLO layer to about 60% and create a new layer beneath it. Make the DLO path active and stroke with a hard edged brush. Apply a guassian blur. Convert the path to a selection and delete the portion of the brushstroke sitting outside your original linework.

Tip. To increase the speed of your work flow use only one path for all the rubber seal, interior edges and shuts around the DLO. Convert the path to a selection and delete on the inside or outside, just keeping the part you need.

With the selection still active paint in the A-pillar, B-pillar, headrest etc. Deselect.

On a new layer stroke the DLO paths with a small black brush to create the window seal. Duplicate this layer and place beneath the original. Lock transparency and fill with white. Unlock the layer and add Gaussian blur if you wish. Using the up, down, left, right arrows on your keyboard move the layer down and to the left.

Select the very first glass layer you created and in the select menu, load selection. Hit ok in the pop up menu and create a new layer. With a large soft brush with low opacity add black across the top of the glass and white down the front edge of the screen.

Create a new path to define the horizon on the glass, this should continue on to the sheet metal of the C-pillar. Convert the path to a selection and on a new layer add black with a large soft edge brush, have the opacity set low and build up the intensity until you achieve the desired effect. Try achieve a graduated tone, darker at the top lighter at the bottom to create more contrast with the white highlight created in the next step.

With the previous selection still active invert the selection and create a new layer. Spray white. Any over spray can be removed by activating the DLO path, inverting the selection and pressing ctrl+x.