Within 3d visualisation, the key to a successful studio is the application of real world photography. In order to get the best results you must apply the same rules and understanding, including lighting position, brightness and size.

There are many photography techniques and set ups that suit multiple scenarios such as portrait, architectural and product photography. One of the most common set ups for product photography is the use of what is known as a key light and a fill light. These lights are positioned over your object whilst the object then sits on a curved background, usually white or black. This tutorial will be split in two parts. The first will explain the theory behind this particular setup and the second will be a short video showing how it can be set up using Autodesk 3ds Max and V-Ray.

Angle of incidence

When a light ray hits a surface, known as the angle of incidence, it is reflected off the surface at the same angle. The surface does not have to be reflective, it can be anything. This can include walls, ceilings and even organic objects such as human skin.

A common problem in photography occurs when the light source is parallel to the back surface causing the reflected ray to bounce right back at the camera. This can be easily seen by taking a photo of an object that is just in front of a window, mirror or any other highly reflective surface.

To avoid this, the camera can be placed to one side. When the ray of light hits the surface at an oblique angle, this causes the reflected ray to miss the camera and is no longer visible in the lens.

Now we have a new problem. The camera is no longer positioned directly in front of the object. To fix this, the light from the camera is turned off and replaced with an additional light source, this known as a key light.

If light rays are lost then the lighting can become poor so the more rays that are bouncing around and reflecting in front of the camera the better. In order to keep the light rays from escaping, a reflector can be used to bounce it back towards the object.

Key light and fill light

The key light is used as the main light source and the fill light is used to reduce contrast. The key light is typically brighter and more prominent than the fill light. This is to simulate natural lighting that would mainly be coming from one direction. However for some product shots it may be desirable to have an even amount of light coming from two different directions.

Reducing unwanted harsh lighting and shadow

A single light source can generate a harsh light that results in high contrast. This can cause unwanted shadows and poor lighting. To overcome this problem, soft boxes are used. The light source is housed within a fabric enclosure that has a diffusing material. As the light bounces and exits through the diffuse layer it scatters producing a very even and soft light that also gives soft shadows. The light bounces within the enclosure because it is lined with a foil that acts as a reflector. Soft boxes come in various shapes and sizes and each producing a range of different results. Common shapes are square, rectangular and octagonal and can be arranged into small, medium and large sizes. There are other types of light sources that are used in photography such as an umbrella, however soft boxes are the most favoured due to the uniform lighting and soft shadows that they can produce.

The soft box can be used for reflection as well as lighting. A single light source without a soft box would create a very small circular reflection, which to the human eye can be seen as un-natural. With a soft box the reflection becomes much larger, more rectangular and looks much more like you would expect if you were to look at the object in real life. A soft box can also minimize shadows and dark areas on the opposite side to the light source. Naturally a small light source would create a shadow on the opposite side. Due to the light box being much larger in size and acting as a diffuser the light can reach around the back on the object.

Position and size

A basic rule of thumb is that the larger the light source, the softer the light will be. The closer the light source is to the object the larger the reflection will be.

• A small soft box at a given distance would create a small reflection and a harsher shadow
• A medium soft box at the same distance would create a much larger reflection and softer shadow.
• A large soft box at the same distance would again increase the reflection and the shadow will become much softer.

Another factor to consider when positioning the soft box is the light intensity. The further the soft box is away from the object, the higher the contrast will be, defeating the purpose of the soft box. If the soft box is close to the object, the light is much softer and more pleasing to the eye, so it is best to keep it close to the object. If you decide first on a large soft box and the position is correct but the reflection is too large, you could try a medium sized soft box instead but keep roughly the same position.

Stay tuned for part two which will show how this type of studio set up can be created using Autodesk 3ds Max and V-Ray.