Filter Forge 11 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.
You can save the animated render result as an image sequence or as a video file in the MP4, WEBM, GIF, and APNG formats. Future Filter Forge versions will add an option to save animations as 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.
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.
If you want to see changes in the rendered image when navigating the timeline, your 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!
Adding Animated Filters to 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.
You can load a single image file or a sequence of images to be used as a source for your project artboard, and also you can load animated and non-animated filters into the project.
Combining a single source image with a non-animated filter is the classic way to use Filter Forge described elsewhere in the manual.
Combining a single source image with an animated filter enables the Timeline for animation. In this case animation duration and frame rate are defined by the Frame Count and Frame Rate components in the animated filter by default. You can override this default behavior by selecting Fixed frame count and Fixed frame rate on the Animation tab in the Artboard Properties.
Combining multiple source images with a non-animated filter allows you to apply a single effect to a set of files at a time. In the Artboard Properties dialog, select External video or sequence, and select the first file in the sequence to load the entire set of images into the artboard. Next, add a filter to the artboard, and select File > Render Animation: the filter will be sequentially applied to all images loaded into the artboard. In this case the Timeline is also displayed but it is not related to animation, it just allows you to preview the effect on any source image before rendering.
Combining multiple source images with an animated filter is another way to create animation. After loading an image sequence the Timeline for animation is displayed, and when you move the timeline head both the source image and the applied effect get changed. In this case the Timeline duration corresponds to the length of the image set. The duration will not change after loading an animated filter, since the length of the image set takes precedence over the frame count specified in the filter. You can still override the duration on the Animation tab in the Artboard Properties. Remember that the image set is processed sequentially: if the user-defined fixed duration is less than the image set length, the remaining images in the set will not be processed; if the user-defined fixed duration is greater than the image set length, the last frame of the animated filter will be applied to the remaining images.
