Im trying to create a FCPX effect in Motion. I want to create a stroke effect for objects with an alpha layer. The built in stroke filter works but does not allow me to change the brush style to more exotic options or apply behaviours to the line. I think I might need to use masks but I can't find a way to get the Alpha mask converted to a shape or points for a pen stroke to follow. How can I create this effect? Thanks
Could you elaborate a little more on the "brush style" and what it's supposed to do?
Also, an Alpha mask to what? Is it a "fixed" shape?
I need to know the details — there may be a way to work out what you want.
Somebody with experience with Pixelmator and importing projects into Motion may have an alternative method for you.
Thanks for the response, The effect is mainly for video Alpha masks created by magnetic mask in FCP so they will be moving. I already have it working so the stroke filter puts a stroke around the edge of the mask but I'd really like to be able to turn the mask outline into a path as I could then add image brushes, emitters, particles and behaviours that I can't with the stroke filter. Hope that helps.
I don't have access to magnetic mask (still in FCP 10.4.10). From what I understand, Motion 5.9 does not have the magnetic mask (yet).
Stroke has the "power" to "Hide Source" which will give you an outline all by itself.
You *could* use the Freehand pen tool and trace the Stroke. You would then have the ability to apply particles and brushes. You can also use the "standalone" Stroke as a *mask* (Stencil Alpha blend mode) to the particles/brushes/etc. and shape outline animations.
The only problem you would have is that the Freehand stroke will need to be animated over time (a matter of setting a first keyframe, advancing the playhead and editing (moving) points to re-match the Stroke as it animates.) This will get to be rather tedius. (Try to move the playhead as far as you can if the movement is "uniform" enough — there's usually no need to keyframe every frame.) If you're experienced with Bezier shapes, try to delete as many extraneous points you can to simplify the process.
[This video might help you simplify your shapes:
https://youtu.be/SXUFGZqF6h4 ]
Converting Alpha Image mask to editable outline
