Basic Blocks are used in the industry to speed up the process of making patterns and for accuracy of a pattern, thus ensuring a better fit.
Patterns are usually developed on cardboard paper using the flat pattern making system (two dimensions). Basic blocks are developed using measurements provided by the Australian Standards Association or they can be made using an indiviuduals measurments. Many Designers and Manufacturers have in house Models and use these measurements in the development of their own Basic Blocks.
Blocks are chosen which are close to the individuals measurments and according to which design they wish to create and then altered to create a new pattern design.
An individual can develop their own Basic Blocks using personal measurments to enable a more accurate fit to use again and again, thus avoiding many alterations.
It is a good idea to analyse each figure type whilst doing block construction and make all pattern alterations required for a perfect fit to avoid any problems being passed onto the next design.
I will be posting more information and instructions on Block Construction for skirts, sleeves, trousers and tops in the near future.