Sometimes a fold looks right until a few steps later, when you find the edges don’t quite match. You might align one corner to another, fold the paper down, and then realize the edges are off by a fraction. In a basic square, this doesn’t seem like a big deal, but each fold after that will depend on how accurately you creased the paper before. Misaligned edges can result in flaps of unequal length, center folds that aren’t centered, and models that refuse to close properly.
Before creasing a fold, allow yourself to move the paper around. Align one corner to the other, hold the two corners lightly between your fingers, and don’t yet press down on the center of the paper. Check that the corners are aligned, then look at the edges of the two sections. If necessary, slide the top section over so the two corners are aligned and the edges are matching, then crease the fold. This extra step is very helpful on diagonal folds, where misaligning the corners can result in large gaps along the edges.
This technique is best learned with practice. Take a couple of square pieces of paper and perform some folds. Fold a piece in half diagonally but don’t crease the fold right away; keep holding the paper so you can double-check the alignment. Do this with an edge-to-edge fold, checking the edges after aligning. Do several folds, examining each one afterward to see if the fold hits its marks. For a diagonal fold, make sure the crease goes all the way from one corner to the other, not just partway to one side.
Use your hands correctly. If you hold one corner, fold the paper, and then press down on the center of the fold, the paper will probably not be folded evenly because the layers are shifting as the crease forms. Instead, align the edges, then crease from the center outwards on both sides. It is not necessary to repeatedly press hard; on a single layer of thin paper, it’s unnecessary, and on thick paper, too many presses will ruin the quality of the crease without correcting the problem.
Reference creases can help you with alignment, too. A center fold, diagonal fold, or the intersection of two creases can help guide you into the correct position. If a model says to fold a flap in, you should check to see if the edges should meet the center fold or if they are meant to meet anywhere nearby. If multiple layers are present, hold the underlying layers near where you want the edges to meet to prevent shifting. As a model grows more complex, these checks become more important.
If a section of a model seems off during a later step, examine the previous steps to see if any errors were made in aligning a crease. Unmatched points or wings can often be corrected by checking the alignment, rather than forcing a part into shape. Always check the alignment of the corners and edges before creasing any important fold. If you’re confident that the corners and edges are correctly positioned, your chances of producing a well-balanced model increase.
