You can either add a regular Maya Area Light, in which case Arnold will assume a rectangle/quad source or if you require a different shape, you can alter the light node type to be an Ai Area Light. There are two ways to use an Arnold area light in MtoA. The built-in lights available in Arnold Area Light Another workaround is to use distant/directional lighting. Similarly, the spot_light in Arnold has a lens_radius parameter that, when set to a non-zero value, and coupled with a low angle, has the apparent effect of flattening the decay, like in a Hollywood-style searchlight. However, Arnold's quad and disk area lights have a spread parameter, that when set to a low value, will give you something similar to a constant fall-off.

Ensure that Light Linking is set to none when instancing lights, otherwise, the instanced light will not render.Īrnold does not support constant light decay.

Information about creating per-light AOVs can be found here.

To improve the quality of the atmosphere_volume shader, you must increase the atmosphere_volume samples.

Volume Samples do not apply to the atmosphere_volume atmosphere shader.

The Maya Ambient light and Volume light are not supported by MtoA.

Similarly, the spotlight in Arnold has a lens_radius parameter that, when set to a non-zero value, and coupled with a low angle, has the apparent effect of flattening the decay, like in a Hollywood-style searchlight.

Arnold does not support constant light decay.

Info: More information about light samples and removing noise can be found here. You can use standard Maya lights when rendering with MtoA. If you select a light and then inspect the Maya Atttribute Editor, as well as the regular light attributes, you will also see a new group of Arnold attributes for the light, which is where any additional settings used by Arnold can be accessed.

The Arnold User Guide provides the full documentation for Arnold lights.

The Arnold for Maya User Guide explains how to set up Arnold lights in the Maya user interface.

Maya to arnold