Lights

Lighting is a key component of how Marso identifies the material properties of a 3D-scanned object. Marso is designed to work with easily accessible lighting hardware, yet there are still key considerations to be made.

A single light works best when placed close to the lens, however, in scenarios where this is not possible, we suggest using multiple lights sequenced one light at a time.

Light Type

For best results, we recommend using as small of a light as possible. Sometimes this can be achieved by removing any diffusion or reflectors attached to an existing light fixture to expose just the bulb.

Open

Open

Small point light,

Crisp shadows,

Sharp highlights

Soft shadows,

Irregular light falloff,

Variable Intensity

Large effective area,

Soft shadows,

Soft / smooth reflections

Light Size

The size of the light source plays a key role in M-XR’s ability to identify roughness. By using a relatively small light source, glossy surfaces can be predicted as the reflections are sharper. It is worth noting that the size of the light source is however relative to how close the light is to the subject.

The example below illustrates this effect when the same-sized light is used for near / far scans

Light Placement

The closer a light is to the centre of the camera, the less apparent shadows will be in the source photography. Reducing shadows, results in better material predictions.

As mentioned in Light Size, this distance between a light and a camera is relative to the overall scale of the scene. An easier way to think about this is with angles, by imagining a triangle between the camera, light, and subject which creates an angle between the light & camera and shown bellow.

For the same camera & light pairing, the distance from the subject can drastically change this angle.

Generally speaking, the further a camera is from the subject, the more you can get away with a light being placed further from the centre of the camera - but closer is still preferable.

Multiple Lights

In situations where an individual light cannot be placed close to the camera, the use of multiple-lights will increase the consistency of material channels.

OLAT (one light at a time)

When using multiple lights, they must be sequenced one light at a time, and in the same order each time the sequence runs for each camera position.

For multiple cameras, only one camera and light pair should be photographed - there cannot be more than one light turned on within a scene, for sequence order please see here. The sequence of lights between cameras should also be consistent.

For example

Placement

When using more than one light source, it is important that such lights can be turned on and off, or triggered individually.

• Use the same brand/model of light

• Place lights opposite one another

• Keep lights rotationally symmetrical

For systems with multiple cameras as shown below - ensure that each light group has the same relative positions as their parent camera.