3D printable boxes with Blender
Intro
I often design custom cases for various things. In this post I will describe how make them with Blender. Note: this is not about doing this the right or optimal way, but this is a way that works for me. 👍
For this you will need:
- Blender from https://www.blender.org/
- The “export-selected” plugin from https://github.com/dairin0d/export-selected/
Step 1
Add a plane and modify it by subdivision/extrusion into the following shape.
Step 2
Add a mirror modifier if you want to save work on symmetrical objects.
Step 3
Modifiy the top and bottom edges to be marked as 100% creases:
Step 4
Add a subdivision modifier to get round and smooth edges. Note, how the the creases are not rounded.
Step 5
Solidify your object. I tend to do most modeling with modifiers, which can be easily changed.

An Object modifier called Solidify. I usually select Even thickness and High quality normals in the options. Select your desired thickness. In this case I chose 1.8mm.
Step 6
Apply all modifiers, then loop cut the top edge to get two rows of faces.
Step 7
Duplicate your object, one for the lid and one for the bottom half.

Hit SHIT+D to duplicate. Then SHIFT+ALT in face select mode to select the inner/outer row of rim faces.
Step 8
Extrude the inner/outer rim for your top/bottom halves of your container.

Hit E -> Z -> 2.5 to extrude the selected rim part towards the top by 2.5mm. I usually extrude the outer rim (top part) one layer (0.2mm) more than the inner.
Step 9
If you followed these steps you will end up with the two printable parts.
Step 10
Select both parts and export them.