Crocodile Clips & Yenka
Yenka Mathematics: making a net

You can use the 2D shapes in Yenka Mathematics to construct your own nets, which can then be folded into 3D shapes.

When you move one 2D shape - like this square - close to another one, the shapes’ edges will snap together.  You’ll see a square block between them when this happens.  Yenka automatically forms a hinge where the shapes join.

Repeat this with several shapes, and you’ll get a net.  One square is darker than the others: this is the base of the net.  You can fold the net up by dragging the corners of any other square, and check if it makes the shape you want. 

Once you’ve folded the net completely, and made a 3D shape, you can double-click on that shape and click “Flatten” in the panel that appears, to flatten out the net.

Try it yourself with the free home licence.