Filter Forge supports animation via procedural rendering. Most animation tools utilize a different keyframe approach, where the software creates interpolation between certain frames. On the contrary, Filter Forge uses filter components that define certain image-altering operations to be performed at a specific time.
At the moment, the rendered animated result can be saved to an image sequence. Future Filter Forge versions will add support for saving into MPEG4 files and sprite sheets to be used in game engines.
If a filter supports animation, select the File > Render Animation... command from the Main Window menu to render the resulting image sequence. For details, see Render Animation dialog.
What Filters Can be Animated
A filter is considered an animated filter when any of the following components are present in the filter:
- Time – outputs elapsed time in seconds from the animation start till the current frame.
- Normalized Time – outputs time from the animation start till the current frame normalized to the 0...1 range. The first animation frame has Normalized Time of 0, and the last frame has Normalized Time of 1.
- Current Frame – outputs the current frame number.
- Frame Count – allows you to specify the number of frames for the animation.
- Frame Rate – allows you to specify the constant frame rate for the animation.
Unlike many other Filter Editor requirements, to make a filter animated these components simply need to be present on the canvas, they don't need to be connected to the Result component subtree.
Timeline
Animated filters can be easily distinguished from non-animated ones since they display the Timeline at the bottom of the Main Window and Filter Editor. Timeline is a navigation bar that allows you to switch between frames in your animation and check on their appearance.
When you move the timeline head the Current Frame component value changes according to its position. You can specify the exact frame number in the Frame Number widget to the left of the timeline and go to this frame directly.
The number of frames in the timeline is determined by the Frame Count component value for non-project filters and by artboard properties for project filters. For details, see Artboard Properties.
In order for changes on the timeline to have any effect on the rendered image, the filter component tree requires a connected animation component that changes its output value in accordance with the current frame, for example a Normalized Time component.
Creating an Animated Filter
Here is a step-by-step guide to creating your first animated filter.
- Open Filter Editor.
- Add any component from the Animation category, for example Normalized Time.
- The Timeline will show up in the preview pane allowing you to navigate through animation frames.
- By default, your animation contains 90 frames. To change that, add a Frame Count component and modify its value. You don't need to connect the component, you can remove it from the canvas after modifying its value.
- Now you need to connect an animation component that changes its output in accordance with the timeline to the main Result subtree. The most basic example of an animated filter is to plug a red Color Control, a green Color Control, and Normalized Time to Blend. This filter will output a 100% red image at the start of animation and a 100% green image at its end.
- Save the filter and exit Filter Editor. You will see the Timeline in the main window preview pane as well. Move the Timeline head to see the red image gradually becoming green.
- Well done – you've created your procedural animation!
Animated Filters and Projects
Animated filters work best when added to Projects, since a Project allows you to apply animated effects to an image sequence rather than to a single file. For details, see Using Animated Filters with Projects.
