Hi, I am trying to scale a square shape using scale height and scale width but when the scale height reaches a certain percentage the top and bottom edges become blurred, is there anyway to stop this blur effect?
Sounds like you are scaling under the 'Video > Motion' section. This applies the scale after the vector shape is rendered so it becomes blurry when stretched.
Use the scale under 'Graphics > Vector Motion' in the Effects control panel. This will scale all the shapes in your Graphics object. Or you can scale the shape directly by choosing it underneath the Vector Motion section.