Using Area Lights
Area lights allow you to cast light more naturallythan directional lights and spot-lights. In this tutorial we'll take one scene and light it using only area lights and Final Gather.
For this set we'll be using a single area light to light a scene in a box. Download the scene set1.mb. This set contains a sphere with a default lambert, and two spheres on top of each other with a shader that looks like a high gloss red.
Step one - Create an area light, move it and rotate it so it is shining down from the top of the box at the objects.
Step two - Open the render settings.
Step three - Set the render using to Mental Ray. On the common tab, roll down and un-check enable default light.
Step four - Go to the tab Mental Ray in the render settings. Set the quality preset to production. Under secondary effects, check Final Gather. The reason we check Final Gather is because Final Gather computes all the light bouncing around the scene. Close the render settings window.
Setting Up The Area Light
Setting up the area is straight forward.
When setting up an area light it's pretty much standard every time. Always remember to check use light shape. Now when you render the image the area light is lighting the scene.