To create a decay light filter, right-click in the GafferThree's Object table and select Add → Decay Light Filter, or press the B key. Decay light filters are not shown in the Viewer, but they do offer a Decay Filter Manipulator in the Viewer, which is explained in a following section.
A decay filter in the GafferThree node parameters.
Decay filters can be applied on area lights, distant lights, spot lights and point lights.
To enable the Decay Filter Manipulator, select a decay light filter in the Scene graph or the Viewer. It will unlock a Manipulators → Decay Filter menu item in the Viewer. Choose this menu item or press the Tab key to display the decay filter manipulator.
Displaying the manipulator will also fill the Quick Editor with the decay filter parameters. The Quick Editor can be displayed by choosing Layout → Show Quick Editor, by pressing the A key, or by dragging the right edge of the Viewer to the left.
The decay filter manipulator offers controls on the Decay Range Start and Decay Range End parameters. Drag the manipulator boxes to edit values. The filter parameters are detailed in the next sections.
The Material tab contains several parameters which are explained in the following sections.
The Material tab of a decay light filter.
The curve gadget is very similar to the Curve Editor:
Points can be added with a CTRL + ALT + left mouse click, or by toggling on the point insertion mode by pressing the Points can be deleted by selecting them and pressing the |
Position
The position of the currently selected curve point.
Value
The value of the currently selected curve point.
Interpolation mode
How values are interpolated between curve points. Available interpolation modes are:
| Value |
|---|
| catmull-rom |
| bspline |
| linear |
| constant |
Presets
A list of predefined curves. Available presets are:
| Value | Description |
|---|---|
| Constant Min | A flat curve set at 0. |
| Constant Max | A flat curve set to 1. |
| Linear Min to Max | A straight line from 0 to 1. |
| Linear Max to Min | A straight line from 1 to 0. |
| Smooth Min to Max | A S-curve from 0 to 1. The lower and higher end values progress more slowly than the middle portion. |
| Smooth Max to Min | A S-curve from 1 to 0. The higher and lower end values progress more slowly than the middle portion. |
| Cut-On-Cut-Off | The curve starts and ends at 0, and is set to 1 for the middle 80% of the range and sharp S-curves for the transitions. |
| Cut-Off-Cut-On | The curve starts and ends at 1, and is set to 0 for the middle 80% of the range and sharp S-curves for the transitions. |