scale works for me - aspect ratio has no effect?
are you sure this isnt something else?
have you checked your channel assignments?
visfx5 keystone
visfx9 keystone setup.
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but you cannot scale an image with keystone points and have the projection stay perspectively correct-
if you use submixes- you can scale an image - and it stays perspectively correct.
to use the building example again- if you set up a keystone mix to 4 corners of the facade of a building - you can move a layer around in xy and scale - and at every point it is perspectively correct.
the windows will line up.
what a keystone does is describe a plane- and how points are mapped from 2d space to projective 3d.