Lighting is a key component of how MARSO Marso identifies the material properties of a 3D-scanned object. MARSO 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.
Works well
Point Light
Built-in camera flash
Small strobe
Single LED
Does not work
Softboxes
Umbrella lights
Reflectors
Polarisation Filters
Ring Lights
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Small point light, Crisp shadows, Sharp highlights |
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Soft shadows, Irregular light falloff, Variable Intensity |
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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
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Smaller Light = Better Materials |
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.
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When there are too many shadows, the shadows themselves can result in artifacts in the form of prediction errors or ambient-occlusion regions being baked into the material channels. |
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Minimal Shadows |
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Too much Shadow |
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.
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We recommend an angle of 3° or less. For anything higher than 6°6.5°, you should use multiple lights. |
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.
Rig Size | Distance: Camera → Subject | Max Distance: Light → Camera |
|---|---|---|
Small | ~50 cm | 4.5 cm |
Medium | ~100 cm | 9.5 cm |
Large | ~150 cm | 14 cm |
To identify the angle use this interactive tool
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.
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Using additional lights will extend the capture and data processing times due to the higher number of photographs being captured. |
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To date, when using multi-lights, M-XR has used no more than 20°. Your scan may work, but we cannot guarantee. |
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
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Camera A - Top, Bottom, Left, Right Camera B - Top, Bottom, Left, Right |
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Camera A - Top, Bottom, Left, Right Camera B - Bottom, Right, Left, Top |
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.
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All three camera groups have four lights with the same orientation. |
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The middle camera group has a different orientation to the other camera groups. |