Advanced Lighting

Advanced Light Materials

The Advanced Materials root node for lights gives you greater control over the lights color input. Most significantly the ability to add light "gels" or "Gobo" materials.

Gobo is a term from the real world lighting industry. It's an object that GOes BefOre the light. A Gobo can be a stencil or color gel placed between the light source and the subject.
 

You can access a light's Advanced Material by clicking the Advanced Material button on the Light Property tab. You can also access the light directly from the materials room on the Edit tab.

Accessing the Light's root node

This will take you directly to the light's root node on the Edit Material tab in the Material Room.

The Light root node will be displayed whenever a light is selected in the Material Room

 

Setting up a Gobo

You can connect any 2D image or procedural texture to the color input of the Light root node to create a "Gobo". This is intended to be used exclusively with spot lights. While you can technically add a Gobo to the other light types it's unlikely to produce any beneficial result. Gobo lights work with both the SuperFly and FireFly render engines. They are not displayed in the OpenGL preview render.

Adding a Gobo makes a spot light work like a projector. It will cast the light using the image for the color of the light in that area. It can be an image or any 2D Image source. 3D image sources while they are allowed to be connected, they are not likely to produce anything but psychedelic results.

You can drag and drop a image into the Edit tab of the Material room to automatically create an Image Map sharer node. Connect the Image map's Color output to the Color input on the Light root node. To make the connection drag the "bulls-eye" dot from one node to the other.

 

An image map attached to the Light root node's Color input.

It probably doesn't look like anything happened when you made the connection between the image map and the light's color input. That's normal. Gobo lights are not displayed in the preview window. You will need to render the scene to see the result.

Rendered Image

The sharpness of the Gobo image is controlled by the scale of the light. If need a sharp image set the light's scale very low. Even to zero. For a softer Gobo effect increase the scale of the light. The scale setting also affects the sharpness of the shadows cast by that light. You think of the light's scale parameter as working like a focus for the light. Smaller scales make sharper shadows and Gobo projections.

Shadow and Gobo "focus"

Other adjustments to the light will also affect the projected image. If you rotate the light the projection will move with the light. You can affect the size of the projection by adjusting the Angle Start and Angle End parameters. These change the spot light's spread angle and the area of the projected image.