Required plugins: Shape3D, Alpha Mask, and AA's Assistant. Note that while you could perform the tutorial without Alpha Mask by using workarounds, it is far easier to explain with it than without.
Step 0: Open Paint.NET. This should, in general, be seen as the obvious precoursery step to a PDN tutorial.
Step 1: Create a new image with the dimensions of 256x256 pixels. Hit Ctrl+A then Delete to clear all the pixels in the image.
Step 2: Rename the only layer from "Background" to "Rectangle". Create a solid rectangle in pure black with roughly the dimensions of a peice of paper. (I used Align Object to center it properly, but that's not neccisary) My rectangle was 175x245.
Step 3: Now create, on a new layer "CornerMask", the mask that will clip off the corner of the page. (In this screenshot I've decreased the opacity of the rectangle's layer so that you can distinguish where the mask lies) It should have a nice 45-degree angle, covering the top-left corner of the rectangle.
Step 3: With the CornerMask layer selected, hit Ctrl+A then Ctrl+C to copy it to the clipboard. Then unckeck that layer and select the Rectangle layer. Duplicate the rectangle layer, and uncheck one of them. Select the only layer still visible, one of the Rectangle layers, and apply Alpha Mask:
Repeat this on the other Rectangle layer in turn, this time checking the "Invert" option in the Alpha Mask plugin. Then rename whichever layer has the "corner" peice to "CurlMask"
Step 4: For the purpose of this tutorial, I'm going to make the page blue for contrast. So, again, create a new layer at the bottom of the list and title it "Page". Fill it with a vertical blue gradient like so:
Duplicate it and repeat the process in step three, but instead of using the CornerMask as the mask, use Curlmask and Rectangle layers respectively on each copy of the Page layer. Rename the Page layer containing the corner to "Curl".
Step 5: Uncheck everything except Curl. Center the curl peice (I used Align Object) and prepare to use Shape3D!
I'm going to attatch an export of the Shape3D settings I used, but feel free to tweak them to fit your image. It should leave you with something like this:
And rotate it about to be oriented like so:
Align the corner to the top of the Page layer and lign it up! Add a little drop shadow and you're done!
Hope you enjoyed the tutorial and didn't get too lost with all the Alpha Masking. But, like I said, the Alpha Masking is optional, and you could technically do this without it.
Have a nice day,
~Sidneys1

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