Graphics Programs Reference
In-Depth Information
the
Size
value is set to
1.000
). At a value of
0.000
, the shadow is at its maximum
crispness, or sharpness. By increasing the
Size
value, the softness of the shadow
increases too.
Differently from the mesh-light, varying the
Size
value of a lamp doesn't require us
to adjust the
Strength
value to keep the same light intensity.
There's more...
In several cases, you would want the emitters to not appear in your render. There
are node arrangements to accomplish this (by using the
Light Path
node in a very
similar way to the
Setting the World material
recipe we have seen before), but the
easiest way to do this is as follows:
1. Start with the last saved blend (
start_11.blend
) with the 3D window
on the left also set to the
Rendered
mode, to see the scene out of the
Camera
view (so the
Emitter
plane is rendered too).
2. With the
Emitter
plane still selected, go to the
Object
window under the
Properties
panel.
3. Look in the
Ray Visibility
tab (usually, at the bottom of the
Properties
window), where there are five items:
Camera
,
Diffuse
,
Glossy
,
Trans-
mission
, and
Shadows
with corresponding checked boxes.
4. Uncheck the
Camera
item and watch the
Emitter
plane disappear in the
rendered 3D window, but the scene still lit by it, as shown in the following
screenshot:
By checking any one of the items, the corresponding property won't take
part in the rendering. In our case, by unchecking the
Camera
box, the
mesh won't be rendered, although still emitting light. Be careful that, at
