How can I use Filter effects from Node library for some keyframes, not for all keyframes. For example, using Blur - Radial Zoom for keyframes from 15 to 20?
Yea, you would just set the blurs to 0 wherever it’s not used. There’s no way to really “disconnect” the blur from something outside of setting it to 0 in a shit, as toonboom is built around doing small shots in their individual project files tailored to the shot.
As said by vrexus you have to set keyframes accordingly. So, if you want a blur with a value of 2, for instance, to be applied between frames 15 and 20, you place a keyframe at frame 14 with 0 and a keyframe with 2 at frame 15. Then you should copy that KF to the last frame you want the value applied, that is, 20, adding yet another KF at the next frame (21) with a 0. This means the value 2 will be applied between 15 and 20, changing from and to zero immediately before and after.
Likewise, if you’d want to animate the blur, for instance from frame 10 to 20, you would put a KF at 10 with 0 (or whatever value you want to start) and another KF with the intended blur (2, for instance) at frame 20. The software will then interpolate from 0 to 2 from frame 10 to 20, so the affected art will gradually become blurred.
This is the behaviour for motion keyframes, you can also use stop-motion keyframes (without interpolation).
Here’s more information about the use of keyframes:
Note that I use “keyframe” in the sense of values, such as motion, position, rotation and scale, as well as the intensity of effects applied to a layer, not in the sense of “key drawings” or “key animation”. That’s sometimes confusing when you come from traditional animation.