light settings

[whatevernevermind]

hi. i have a question about light settings. recently i watched a keyshot tutorial video. at 0.31st second  a plain was added. for material choosen light. and plain was hidden but plain's light was appear. how could it be.
http://www.youtube.com/watch?v=-nY0zBc443w

[Ed]

Double-click on the emissive plane to open the Material Editor.  The material type should be "Emissive"  Un-check "Visible to Eye"

Now it will continue to emit light, but the object is hidden.

Ed

[whatevernevermind]

thanks.

[elliasp]

About this topic, do you know if the render time is better when light emissive objects are hidden ?...

Indeed, it should take more time for the computer to calculate an emissive object, no ?...