The inspiration for this image came from an old photo of a meter in an abandoned factory.
I started by making a simple cube against a vertical grid. The meter originally had a thin wire coming out from below. Since this lacked a personality, I decided to replace it with a thicker metal cable, the type you find in old public telephones. Next, the smaller details of the meter were added. I deliberately avoided beveling any of the parts, choosing instead to achieve the look in texturing. This approach keeps the whole set extremely light and is commonly used in the gaming industry.
I did a basic lighting first before getting into texturing. To simulate the sun, a spotlight with high intensity & yellow color was used. Two additional white fill lights were also used. To get a tint of blue in the shadows, I gave a negative shadow umbra value to the key light. By doing so, the shadow gets a color oppposite to the light color and in this case blue is oppposite to yellow.
Having a large collection of textures & good photos serves as a good hunting ground to get things started. After finding the right images, I started cleaning them of unwanted details. The clone tool in Photoshop was particularly helpful in this. For texturing, I always prefer hunting for a good photograph similar to the desired look rather than blending multiple textures. I believe 'Natural' is best. In some cases, bits of an image were cloned repeatedly to create a much larger image. I normally do texture layering in Photoshop & prefer importing the flattened texture into Softimage XSI. Mixing textures in 3d is minimised as far as posible. This approach makes your work easily portable across different softwares.
Once the textures fell into place, I was not very happy with the initial lighting. The image didn't convey enough, if you know what I mean. To add the illusion of the whole set being larger than what it was & also for a better image balance, I needed some shadows falling onto my scene. I achieved this by placing 2 boxes - one on top and one on the right side of the Meter. Though they themselves are not visible, their shadows cast a nice look. I used an XSI shader called Dirtmap, which works on the ambient occlusion principle, for generating a diffuse shadow layer. The shader is available for Maya also but if you don't have it, try getting a similar result with Final Gathering / Global Illumination techniques or even through a dome-shaped array of shadow casting area lights.
Using the Adjust\Curves tool of Photoshop, I lifted the blacks in the render & then increased the saturation slightly to bring out the rust colors. The shadow layer was rendered separately and with the 'Multiply' option in Photoshop, placed on top of the normal rendered image. However, this makes the shadow regions lose their color and it changes to black or shades of grey. To compensate this, I made a copy of the bottom most layer & layered it on top of the shadow layer with 50% opacity and theblending option set to 'Color'. Now the shadow regions take the original color of the underlying image. Next, a black & white noise layer was prepared using the 'Noise' filter, blurred slightly & layered on top of the previous composition with an opacity of 10% and blend option set to 'Soft light'.
The rusty meter is ready for display at last!