how do i stop this from happening?
Work at 100% zoom and make sure to use full integer pixel values for everything. AE operates sub-pixel precise and working at higher zoom levels or using fractional values will cause things to end up "between pixels" and introduces additional antialiasing. that may not always be desirable...
Hi- thanks for the reply.
When i zoom it to 100% it seems fine but a little edgy still?
So are you saying that this is how it is? It's only like that cause the zoom leverl was in?
You misunderstand. Of course when you zoom to 100% after the fact, nothing changes. You can then only numerically correct the values by revealing them in the timeline. Your shape might in fact already be at the correct position, but you may have made it 100.5 pixels wide or something like that, so the edges never align cleanly. It's always a combination of these things that causes mayhem. You may avoid the issues however by working at 100% in the future or smaller even. Other than that antialiasing is usually desirable, but if you still want to turn it off, you can set the layer to draft quality.
thank you for your help.. much appreciated! Also once i render this will that problem go away?
As its just happening while im creating/ram previewing? (havent rendered as yet).
Not necessarily. What you're seeing is anti-aliasing, which occurs when a pixel's position falls in between two lines within your comp's resolution. If the x position value of your layer is a whole number it will look clean, but if it's a fractional value, like 10.5, After Effects will antialias the edge, to compensate for the fact that the pixel is not truly at horizontal position 10 or 11. This is further complicated when your layer is scaled.
This is an essential smoothing process in graphics rendering, but it pays to be conscious of it and use whole integer values when possible, as Mylenium explained.
What you're seeing in preview is typically what you will get when you render.