Custom shader properties cannot be seen on the Blend UI such as in picture below :
By looking at source of DropShadowEffect (which is part of WPF), animatable properties have been defined like this :
DropShadowEffect.ShadowDepthProperty = Animatable.RegisterProperty(...);
Unfortunately, Animatable.RegisterProperty method is internal what forbids doing so, the only way working is to manually code a storyboard.
Is there a way or a library that would allow to have this ability back for custom shaders ?
Found the origin of the issue : the URI of the shader was incomplete !
It should be like this :
var pixelShader = new PixelShader();
pixelShader.UriSource = new Uri(@"pack://application:,,,/YourAssembly;component/YourEffect.ps", UriKind.Absolute);
Subtlety : do not forget the @
Reference :
https://stackoverflow.com/a/13112241/361899
Properties are back now :)
Note : all previous stuff on question (Animatable) is not needed anymore.