Photoshop and Symmetry. Opposite directions...

We all know that Photoshop is a great tool, and even if some digital artists work mainly with other programs like Corel Painter there will always be a moment when you need Photoshop.

Painting, scaling, adjusting, deforming, warping, enhancing, optimizing, etc... you almost can do whatever you want with Photoshop. Almost...

There is apparently something that Adobe don't want to develop, a tool so useful that could change our everyday work with Photoshop, a tool that is already implemented in so many other softwares: Artrage, Corel Painter, Sketchbook Pro and even Alchemy... The symmetry tool!

I still don't understand why there is no such a useful feature in Photoshop. 

But is there any way to do it? Can't we use a script or any kind of trick to simulate these real time symmetry tools you can find in Painter or Sketchbook for example. Unfortunately the answer is no. Nothing that will look the same or work identically. 

The first method we all tend to use when we work in Photoshop is to draw first half of the drawing on a layer then duplicate it (Ctrl+J/Cmd+J), then flip horizontally this second layer. And repeat this action as many times as necessary. Most of Photoshop users do this.
Of course we can script this action to make it less repetitive but we will always have to, at least, reposition the new layer.

Duplicate first layer. Flip horizontal.

Another method, more creative, consists of creating a Smart Object from your initial layer, then duplicate this smart object and flip it horizontally.
When you double click on your first Smart Object it will open a second Photoshop document (.psb file). Organize and arrange your windows with a horizontal tiling in order two see what you draw in your instance (.psb file) and the result in your main document (.psd file). Unfortunately this instance is not updated automatically and you will have to save (Ctrl+S/Cmd+S) whenever you want to see the result. So it is quite good but not perfect.

Transform your layer in Smart Object, duplicate it and flip horizontally.

Double Click on your Smart Object Layer.
Arrange windows to show your master document and your Smart Object.
Draw in your smart object and save to update your master document.

So, that's it? Nothing else, better or optimized in Photoshop?
Well to be honest I tried another method but this one is definitively very tricky. First of all you need to work with Photoshop Extended version to be able to work with the 3D tools. Then the idea is to create a 3D instance with the 3D Photoshop menu, then create a plane in a 3D Software (3DS Max or Maya for example) then duplicate the first plane and flip it. But this method is highly unresponsive unless you have a NASA computer. Complex and laggy it will not help you working on big documents.

So no miracle or super trick to draw with a real time symmetry tool in Photoshop. Just do it with other software that already allows you to work with X axis, Y axis, custom angle axis, etc... Waiting for the day when Adobe will implement it in Photoshop. :(