How is volume used in fashion? Volume is used to change the silhouette.
(images lifted from the web)
Usually the change in silhouette is to conform to fashion. Sometimes it is to redirect attention away from certain parts (or nearly all) of the figure.
It seems obvious, but you can only use volume to increase the size of some or all of the silhouette – it can’t be used to reduce. This increase in size is often used to offer a note of contrast. Please examine the picture of the bustle to your left. Not only is this a show of wealth (the fabric, the trims) it also emphasizes the slender and somewhat severely dressed woman to the front of the dress. The look works with a tightly laced waist, enough height to make that waist evident between the bust and bustle, and a flat belly. It is nearly always paired with tightly-fitted sleeves. The contrast between the close-fitted, almost severe dress and the wanton bustle is what brings visual pleasure.
Missteps happen when you look at a fashion model or sketch of an outfit and assume that the volume will look as pleasing on you as it does on them. This is not necessarily true. Fashion models and sketches are almost invariably elongated. This means that the article of clothing tends to be less voluminous on them (tall – they have more surface area to cover) and more pleasing to the eye, because it balances with slender limbs. Notice the picture of the heavy sweater to your right – that silhouette was meant to be charming and childlike… and indeed it is, because it visually shortens and widens the figure. Fine for the model, possibly not fine for you or I.
The artistic heart often finds itself drawn to clothing with a great deal of volume, clothing that is art in itself, rather than clothing that is intended to display the figure. Regardless of the desired effect, remember visual balance is important. This is an excellent time to deploy the camera.
Rule of thumb on volume for figure flattery: Skim the areas you find too large, enlarge the areas you find too small, emphasize the bits you want to display – and keep proportion uppermost in your mind. It does *not* make you look thinner when you wear a sack dress, it makes you look bigger, because volume can only increase your silhouette.
That’s your choice – but you must make it with eyes open.