Gaussian

Photoshop CS2 has the vanishing point tool that works with a grid. What few people know is that you can actually save this grid to your document by holding down the Alt key (Option key on the Mac) and clicking on OK.

This could be useful if you want to draw in perspective as shown in my second screenshot. Like with most of these tricks... it's all up to our imagination what we're going to do with it (which makes Photoshop a continuous journey full of discoveries). Some might want to use it for an effect and combine it with a filter.

Gaussian

Just fiddling with it...


You will notice after using the above instructions that the grid lines aren't anti-aliased. For that you need to use the trick that I often used with Polar Coordinates; create a document that is much bigger than you need and size down after applying the grid, in this example I sampled down from 3000x2000 pixels, it makes the lines much smoother.

So maybe this example can help you to memorize the vanishing point grid, you never know when you might need it.

Feel free to share a quick little design that makes use of the grid or suggest other uses for it.