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Add ambient shadows to surfaces

Add ambient shadows

Materials

 

Add lighting and the environment > Add ambient shadows > 

Advanced ambient shadows settings

Why adjust ambient shadow settings?

Standard ambient shadow calculations may make objects too dark or muddy in certain situations. You may want to:

1. Make objects that are occluded by other objects stand out better (such as car accelerators or interior controls).
2. Make the shading more vivid for indented objects (such as the keys on a keyboard). Make concave surfaces clear (less “muddy”).
3. Reduce the effect of ambient shadowing by adding more illumination to an object.

Number of samples

When calculating ambient shadows, the software shoots out a hemisphere of rays (samples) from a grid of sample points on the surface, and calculates how many of these rays hit other geometry. The larger the proportion of rays that hit other geometry for any particular point, the darker that point will appear.

A small number of samples means a fast calculation. A large number of samples means a slower calculation time but could result in more realistic ambient shadows.

Shadow map resolution

Shadow map resolution determines how many sample points are used per given area to calculate ambient shadows. A higher resolution (with a large number of samples) could result in sharper detail, but will take longer to calculate.

A resolution value of 1.0 is recommended. A value less than 1.0 will provide a faster calculation time, but poorer results. Values higher than 1.0 will give sharper detail, but will increase calculation time.

This value is related to the texture resolution used in materials, and influences the size of material textures. For example, a shadow map resolution or 2.0 will result in material textures of roughly twice the area of those with a shadow map resolution of 1.0.

NoteYou can tell when higher sampling or resolution is required if surfaces show dark patches, “burn marks” at seams, blotching, or other blemishes.

Shadow samples spread

By default, sampling rays are cast (or spread) in a hemisphere of 180 degrees. Use this setting to reduce this spread to a smaller angle.

This setting is particularly useful to add detail to grooves or surface depressions (for example, the indentations around keys on keyboards).

Use drop-off

Select this check box to consider the distance of surrounding objects as one criteria when calculating ambient shadows. Drop-off is useful to lighten up surfaces in corners or recesses that are surrounded by other surfaces.

(When this setting is not checked, the same level of ambient shadowing is calculated for surrounding objects, regardless of their distance away.)

This check box must be selected to use the following controls:

Drop-off distance

Specifies the drop-off distance (that is, the distance beyond which surrounding objects are no longer considered in ambient shadow calculations).

Drop-off rate

Calculates lighter ambient shadows as surfaces are further away from the sampling point.

An Abrupt setting creates darker ambient shadows for surfaces close to the sampling point, and then quickly reduces the influence of surrounding objects the further away they are.

A Slow setting creates the same brightness of ambient shadowing regardless of the distance of surrounding objects, up to the drop-off distance.