BBU — connecting the units and different connection methods

Back to Building Block Units (BBU)

Folding BBU units is described in other sections of this tutorial while this section focuses on connecting the units once you have folded them.

Cubic connection method and paneling

The body of most models consists of cubes folded just as they would be with the business card cube module. Likewise, the external surface can be covered in a kind of paneling which improves both the looks and the stability of the model.

Diagrams — downloadable PDF files

These diagrams show roughly the same content as the photo-tutorial below, but use drawings rather than pictures.

Cubic connection method

Cubic connection method — paneling the side walls


This phototutorial presents roughly the same content as the drawn diagrams above, but combines both into a single sequence of first connecting six A1 units so that they form the interior of the cube (this is the cubic connection method) and then adding additional six A2 units as an outer layer for better looks and stability.

Step 1
1. Start by making a single vertex, consisting of three units.
Step 2
2. Each unit’s flaps should embrace two other units in the finished assembly of six. Note that the assembly will be very fragile until you connect all six units.
Step 3
3. All six units connected. Depending on flaps’ size, they may overlap on some faces while there will be free space between flaps on other faces.
Step 4
4. Attach an external tile with the help of internal units’ flaps. You may slightly open the internal cube while adding external tiles. You can also roll the flaps a little in order to squeeze them into their pockets.
Step 5
5. External tile fully attached.
Step 6
6. All external tiles attached. External tiles improve not only the look but also the stability of the model.

Extended cubic connection methods

Flat connectors (A5 units, sometimes with additional creases) can be used to attach cubes to each other along any edge, as can be seen in the Abstract Composition “T” model. Tile D1 and its variants can be used to connect cubes diagonally at the corners, and slits such as B2 can be used to attach cubes at almost arbitrary positions along other cubes’ edges.

Flat / Sonobe connection method

Flat (or curved) surfaces can be made from “superunits”, assemblies consisting of two tiles connected to each other by their flaps and a connecting A5 piece inserted between them. This creates a Sonobe-like structure: parts of the connector unit can be inserted between units from another superunit. This is similar to how Tomoke Fuse’s Square Flat Units are connected but with a larger connector.

Flat / Sonobe connection method

Hook connection method

For models which require extra strength, flat sections can be made from A2 tiles with the flaps of A1 tiles inserted into the internal creases of A2 units. Units must be folded with x = ½ (that is, with symmetric instead of arbitrarily placed folds) in order for this to work well. Since paper thickness is not zero, usually a tiny bit of extra space must be left between the folded edges for the other unit to fit into.

Hook connection method

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