Couple of things to keep in mind with your photo selection. This effect will work best with simple line art. Too complicated and the 3D tools in Photoshop will balk. Each section that you want to be 3D needs to be a completes section, if there is section where the lines do not connect, you will not see has dramatic a effect. mmm kay.
Open your image in Photoshop.
Isolate your image from the background.
Duplicate the working image.
The duplicate image is what where going to use to create our selections. Grab a standard round brush, set the hardness to 95% and go about connecting an areas that are not complete.
Separate the head from the body, There's a couple of ways to do this, one is to use the pen tool to create a new selection around the head, this is what I used initially but I think it would far faster to do it the following way. CTRL+CLICK on the thumbnail of our working image. This is going to select the whole image. Grab the Marquee tool and while holding down the ALT key de-select everything but the head.
Create a new layer and fill it with black, turn off the working image and the duplicate and you should have just the head of Calvin. Using the Magic wand brush, make a selection of the outside of Calvins head, Press CRTL+SHIFT+I to reverse the selection. With the selection fill with #fee2ba
Fill the selection by pressing SHIFT+F5 and then enter.
Goto the 3D menu and select Repousse.
Press okay and you should have something like this.
Right click on the layer and select Rasterize 3D.
Disable this layer for now.
Re-enable our duplicate Calvin layer. Using the same process as we did for the head, create a selection of just the body.
Create a new layer but this time fill it with #df0400
You should have something like this.
Goto the 3D menu and click on Repousse.
Should end up with something similar. Right click on the layer to Rasterize 3D
Duplicate the same process for the feet but this time fill the selection with white.
Be sure to Rasterize 3D.
For this step we are going to need to use the Pen tool to create a selection around Calvin's hand.
Click to zoom this image
Next use the Convert point tool to adjust the nibs around the selection. Once your happy with the paths, click on the Paths Tab.
At the bottom of the paths tab you'll see a small circle of dots, click on it to change the path you created to a selection.
Create a new layer and fill the selection #fee2ba
Goto the 3D menu, Repousse, use the same settings as before
You should end up with something similar.
Right click on the layer and Rasterize 3D.
Now you should have something similar to this.
Move the original Calvin layer so it's above the 3D layers.
To create Calvin's hair, we'll use the pen tool to create a path, focus on the hairline and don't worry about the hair.
Create a new layer and fill the selection with #fccb05
You should end up with this:
Clean up the excess yellow, select Calvin's 3D head and using the magic wand make a selection.
Select the previous layer and press the delete key to get rid of the excess yellow. There may be a little yellow peeking out around the black outline, use the eraser to remove it.
Change the layer blending mode to soft light.
Select Calvin's arm.
Select the brush tool and change the color to #df0400
Paint in Calvin's Sleeve.
Double click on the layer to open the blending option box, select drop shadow.
Why were working the arm, we need to fill in the small section on the left of Calvin. Select color #fee2ba and paint in that small section.
Lastly we need to pain Calvin's socks. Select color #d34956
Paint in Calvin's Socks
That's it - Congratulation your done.