Draping is the process of transforming a clothing design into a three-dimensional form. The art of draping dates back to 3500 BCE, beginning with the Mesopotamians and Ancient Egyptians.
In fashion, a drape is basically the way fabric hangs or falls. Things like skirts and dresses naturally have this sort of element, but designers often find ways of playing with angles and lengths to make the garment more artistic and interesting. Draping also finds its way into other garments, particularly shirts and coats. Fashion trends often feature angular, billowing, or otherwise distinctive fabric “falls,” either to attract attention or to say something about the wearer’s style and taste. They can be added to clothing for men, women, or children, and can be used in just about any garment. Many designers choose to experiment with the way fabric hangs, but there are also objective ways to measure this feature, both for creation and wearing purposes.
Basic Idea
Making clothing can be a somewhat involved process, and there are a lot of things the designer needs to consider. Draping is one of the most important. Different fabrics have different weights and textures, and as such they fit differently and hang differently from the body. Something like silk that is really smooth and almost slippery necessarily hangs differently than something made of muslin or stiff cotton. Designers and creators usually take these and other factors into account when creating garments; they also usually play a role when it comes to things like sizing determinations so that a certain look can be consistent from size to size.
Creation and Conception
Draping usually begins with a designer taking a basic garment and putting it on a dressmaker's model. The garment is generally already sewn into its core shape — for instance, a bias-cut dress would start out as a bias tube on the model. Next, the designer takes pieces of fabric and pins them to the garment where the draping is desired, which will give the final garment its shape.
Adding fullness: Applies when design fullness is greater than the dart excess can provide. Added fullness is not directed to the pivotal point (bust). Adding to the pattern's outline also indicates that added material is needed for the design.

Contouring: Fitting to the contour above, below, and between the bust, leaving the dart excess to be absorbed into stylelines or gathers. Gapping ease caused by cutout neck lines and armholes is transferred to be absorbed.

Dart equivalent: A creative dart that functions as a dart in the sense that the fit is not adversely affected.
Dart manipulation: Changing the location of a dart within the pattern frame. Remember that the dart is responsible for fit and will be part of the design in one form or another.
Design analysis: Through design analysis, an experienced patternmaker is able to identify which principles and techniques to apply in developing correct pattern shapes that end in a three-dimensional replica of the design.
Design pattern: The finished pattern that contains all the features related to the design.
Flat patternmaking: Major patternmaking principles and techniques: dart manipulation (relocating darts), added fullness (adding more fabric in the design), and contouring (fitting to the hollows of a model's figure).
Pattern manipulation: The act of slashing and spreading or pivoting a pattern to alter its original shape. The new pattern shape represents design features of the garment.
Pattern plot: The act of placing lines on a traced copy of the working pattern relating directly to the design features. The lines are used as guidelines for pattern manipulation.
Pivotal point: A designated point on the pattern (for example, the bust point). The pattern is slashed to, or pivoted from, this point. This allows the pattern shape to be altered without changing its size or fit.
Test fit: A process where fitting problems are located and corrected.
Working pattern: Any pattern used as a base for manipulation when generating design patterns.