I have tried for a long time to figure out the magic formula to create gave walls without a ton of effort. I believe I have finally found a way.

To do this you will need to obtain Paint.net. It is a free graphics program available here.

1.       Open Paint.net

2.       Create a new file.

File > New

 

 

 

Change the size of the picture. For this example I will do a 6” x 6” tile. You can choose to do an entire map at one time or in any size sections you want.

 

 

3.       No clear out the background so it is transparent.

a.       Click Ctrl+a on your keyboard to select the entire picture.

b.      Click Delete on your keyboard to clear the selected area.

 

 

 

4.       Select the Brush tool 

 

 

 

 Set the Brush width to 10. The primary color should be black by default.

 

 

5.       Draw a line in the shape of the wall you want to make. Be sure to draw all the way to the edge of the canvas on both ends of the line unless you want to create an entirely enclosed space. If that is the case make sure both ends of the line end on top of each other.

 

 

6.       Select the Magic wand tool

 

 

 

Set to Selection Mode, Flood Mode, and Tolerance to 50%

 

 

 

7.       Click in the area that should be behind the wall.

 

 

 

8.       Select the Paint Bucket tool

 

 

 

Set to Flood Mode, Solid Color, and Tolerance to 50%

 

 

 

9.       Click in the selected area (It may not appear blue any longer) to fill.

 

 

 

You may still see a bit of a clear line between the fill and the drawn line. That’s ok.

 

10.   Invert the selection click CTRL+i on your keyboard

11.   Add a Gaussian blur effect.

Effects > Blurs > Gaussian Blur

 

 

 

Set the radius to 50 for a light shadow 100 for a deep shadow. If you would like a darker shadow you can repeat this step.

 

 

 

12.   Invert the selection click CTRL+i on your keyboard

  

13.   Click Delete on your keyboard to clear the selected area.

 

 

 

Note: If you wish a result with sharp edges. Continue to step 15. If you wish to have rounded edges continue on.

 

14. Round Edges.

Effects > Photo > Glow

 

 

Set Radius to 20, Brightness to -100, and Contrast to 10

Repeat step 13 for a more rounded edge.

 

15.   Click CTRL+d on your keyboard to deselect.

16.   If your work is smaller than the canvas you can select the area and crop it.

17.   Save your work as a .png file.

 

Here are our results. From left to right hard edge, hard edge with two shadow passes (@50), two shadow passes and two rounding passes.