Good subjects have a fairly compact, simple structure with lots of surface detail. Examples include human faces, some animals, fruit, pots, stuffed toys, and some statues. Other suitable subjects are shown in the Gallery on this website.

Poor subjects often have either a complex structure, little surface detail or are very shiny or polished.

Generally such subjects will result in an inferior quality 3D model. Examples of poor subjects include plants, flowers, whole animal skeletons, engineering structures where the internal structure is visible, and subjects with many 'holes' through the structure.

Other unsuitable subjects are those with little surface detail or which have shiny or polished surfaces, include many man-made plastic and metal objects.

However sometimes the scanner can create an acceptable 3D model from such objects. To some extent it is a matter of trying, and examining the result. You will soon get an idea of what makes a good subject.

The Scanetica 3D Scanner requires two good quality (stereo) photographs, with greater than about 1.5 megapixels. Suitable cameras include high quality SLR type cameras, as well as compact digital cameras and some types of camera phones. In addition the two photographs can be taken with either one or with two cameras.

One Camera

The most accurate models are made when there is no movement in the subject in the interval between the two photographs. Even very tiny movements may affect the accuracy of the model. So with people it is important that they try to remain as still as possible, and the time between taking the two photographs is as short as possible, to minimize any movement that is unavoidable.

Of course, inanimate objects generally make good subjects even when using a single camera.

Two Cameras

Two cameras have the advantage of allowing almost simultaneous photographs. With practice it is possible to get the interval between the pair of photographs down to a small fraction of a second. This is likely to give more accurate models of subjects such as human faces, as well as allow reasonable models of some animals.

The two cameras do not need to be of the same type, make or model, as long as they can both take good quality photographs with greater than about 1.5 megapixels. The two cameras could be mounted on two tripods, or, more easily, on a suitable dual camera mount such as described below.

The most important aspect of taking stereo photographs for use with Scanetica 3D scanner is to have suitable lighting. This may be natural lighting outside or artificial lighting inside. Wherever it is, you need bright, even lighting.

Outside

Choose a location that provides diffused, bright, even illumination.

On a sunny day, direct sunlight will cause heavy shadows. Consequently you will need to find a shaded area with solid shade. Speckled shade that is often found under trees and bushes will not be suitable.

Cloudy days provide diffused light, which generally provides ideal lighting conditions.

Inside

Natural sources of bright and even light are generally unavailable at inside locations. Even a large window looking out over a bright sunny area does not give even lighting. Therefore, photography inside requires some sort of artificial lighting. Care must be taken to avoid shadows on the subject. A single artificial light, or light from a single window, will cause shadows. Therefore multiple lights must be used.

It is also important to avoid reflections. Reflections can create strange 'holes' in your 3D model. Generally the smaller the source of light, the more likely you are to create reflections on your subject.

Given these problems, several fluorescent lights are best since they will reduce the problem of reflections. Otherwise several halogen lights or even strong tungsten filament lights may be suitable. In each case after arranging the lights to give even lighting over the entire subject you should ensure you adjust your camera for the correct colour balance for the type of light source you are using. (Refer to your camera's manual for further information).

Camera Flash

If you are having trouble finding a venue with suitable bright, even lighting then you could try taking the photographs with the camera flash. This can give reasonable results with non-reflective subjects although the sides of the subject may appear too dark and the delay in recharging the flash for the second photograph may allow too much movement if using a single camera with a person as subject.

When choosing a location, it is best to choose a place that will give a neutral background behind the subject if possible.

The colour of the background is important. If the background is bright white or very dark, the automatic exposure setting on most cameras will result in an under- or over-exposed subject. Also if the background is strongly coloured, the colour balance of the subject may be affected giving an oddly coloured model.

A flat background without detail is not essential but will assist you in 'clearing' the background, a step you need to do before the program can make the model. The aim of clearing is to define which parts of the photograph are to be included in the final model. A good background can be provided by using a large piece of light grey card, light neutral coloured cloth, or a painted wall.

One Camera

The simplest way of using a single camera to take suitable stereo photographs is to hand hold the camera; no mount is required. This allows you to move the camera sideways and take the second photograph as quickly as possible, which is important for human models.

Two Cameras

If you are using dual cameras to take the two stereo photographs then having them securely mounted enables one person to take simultaneous photographs. The best solution is to use a dual camera mount. Such a mount can consist of a wooden, plastic or metal bar upon which both cameras can be mounted and which itself can be fixed on a tripod, as shown opposite.

It would also be possible to have the cameras mounted on two tripods, although you may have problems setting them up a reasonable distance apart (ie one tenth of the distance to the subject).

A particularly easy way of making models of many subjects, including very small subjects, is to use a turntable. This eliminates any guessing as to whether the angle of the stereo photographs is reasonable, and generally makes taking photographs easier. This method requires only a single camera.

You may already have a suitable turntable. If not a simple cardboard turntable is easy to make using the instructions provided here.