When selecting a bag shape, it is important to determine if the final product will be soft, semi-structured, or structured. These decisions can alter the shape of a bag well before adding pockets, straps, and closures. A soft material like textile might conform to the shape of what’s inside, whereas a sturdier fabric or leather will be better suited to a more geometric shape. This affects the shape of the sides, gussets, base panels, and opening, as well as where the hardware will be placed. Knowing ahead of time whether a bag design should be collapsible, somewhat structured, or completely structured makes planning much easier.
To get a feel for what soft, semi-structured, and structured means, take a basic tote or shoulder bag design and sketch it three times. First, sketch a soft version with noticeable folds and a relaxed side silhouette. Then, sketch a semi-structured version. The side silhouette should have a bit of movement, but the bottom and top should have more rigidity. Finally, sketch a structured version. The sides should be straighter, the gusset should be firmer, and the bottom should hold its shape. Use roughly the same dimensions across all three sketches to compare the effect of adding structure without making major changes to the design.
Soft bags rely on fewer precise dimensions and measurements. The sides can flex or move with the contents, and the base may become flat or bend in the absence of anything inside. This allows for many variations on a theme, such as a casual tote, drawstring shape, or lightweight shoulder bag. However, soft materials can cause problems such as pockets that sag, zippers that distort the opening, or a loss of the depth planned out in the sketch. Because the soft fabric doesn’t retain its shape, additional reinforcement may be needed for strap attachment points.
Semi-structured bags lie somewhere between soft and structured. While the main body is loose, other parts of the bag are stiffer, such as the base, opening, or flap. New bag designers often struggle with the concept of a semi-structured bag because different parts don’t necessarily behave in the same way. There may be a stiff lining, interfacing, seam, or edge supporting one area while other areas drape and move. The bag sketch should make note of which parts are semi-structured.
Structured bags have more defined proportions and construction. Straight sides, distinct gussets, firm corners, and solid openings make small differences in measurements more apparent. The scale of hardware can make a big difference. A larger buckle or D-ring can work on a structured bag, but may look out of place on a small structured bag. Furthermore, if a material and reinforcement produce a structured silhouette, errors in flap size, strap position, or overall depth will be easier to spot.
When looking over your bag design sheet, consider how it looks empty, then how it looks full. Is the silhouette sensible in both states? Would the soft version collapse too much? Does the semi-structured version require reinforcement for the opening or base? Is the structured version too stiff for the bag’s purpose? Noting how the material will perform is an easy way to ensure that the shape feels right before you start cutting and sewing.