Photoshop Mirror Symmetry Action

MirrorSymmetryActionHeader Unfortunately Photoshop does not have a live symmetry drawing tool, however you can get something almost as good using a simple action. Below are the steps you will need to create it. I'm using Photoshop CS 6 for this but I'm pretty sure this should work in most older versions and I know it works is the new CC version. If you haven't used Photoshop actions before, take a look at Matt Kohr's excellent introduction to actions over on Ctrl+Alt+Paint.

This action takes whatever artwork is on the right side of the current layer and copies it to the left side, replacing whatever was there. Symmetry is over the Y axis at the center of the canvas. I'm going right to left here because I'm right handed but you can use this same method to mirror in the other direction or top to bottom. Here is the basic idea of what we're going to do.

  • Select the left half of the canvas.
  • Delete it.
  • Duplicate the current layer.
  • Mirror the new layer across the symmetry axis.
  • Merge the two layers back into one.

And here are the action steps:

  1. ⌘ + A : Select > All
  2. Select > Transform Selection While the transform is active, change the reference point location to the left center point. Then set the width value to 50%. Make sure that the Maintain Aspect Ratio button is NOT checked. You want the height to stay at 100%. Hit Enter TransformSettings
  3. Del : delete the content of the selection
  4. ⌘ + D : Select > Deselect
  5. ⌘ + A : Select > All
  6. ⌘ + J : Layer > New > Layer Via Copy
  7. ⌘ + A : Select > All
  8. Select > Transform Selection While the transform is active, this time change the reference point location to the right center point. Then set the width value to 50% as before. Hit Enter
  9. ⌘ + T : Edit > Free Transform Now, while the transform is active, this time change the reference point location to the left center point like you did in step 2. Then set the width value to –100% (that's negative 100%). Hit Enter
  10. ⌘ + E : Layer > Merge Layers
  11. ⌘ + D : Select > Deselect

I have this action set to trigger with F6 so that I can make a few strokes with my brush, then hit a key and update the image. It's not quite a live effect but it's pretty close.