Graphical Method and Advantages and Disadvantages of Graphical Method

Graphical Method of Material allowance calculation

• The complete patterns for 1 pair are arranged go in the foremost compact and economical arrangement onto a graph paper. 
• A rectangle is then drawn round the patterns that encloses the set.
• Sometimes, the line cut across the patterns to a degree as like within the example. 
• This assumes that the components that protrude might be accommodated in the gaps within the rectangle.
• The area of the parallelogram  is calculated by multiplying the length by the width or counting up the amount of squares covered.
• A percentage is applied to the present area to calculated an allowance for the pair.
• The percentage will usually vary according to:

1. Material type 
2. Material quality
3. Average pattern area in relevancy to average material space.
4. Variation in size and width fitting

These percentages are generally based on previous expertise and few companies apply the similar percentage for all styles and materials.

Advantages of Graphical Method  

• Reasonably quick and easy to use.
• Permanent record of the calculation method.
• The same base area may be used to calculate allowances for various materials, qualities, and sizes.
• Less skill is needed than the marking up method.

Disadvantages of Graphical Method: 

• It is subjected because the original rectangle area could vary significantly depending on the interlocking skill of the assessor.
• The percentages applied are based on previous cutting history which can mirror uneconomical cutting.
• There may be no previous expertise of special materials so an estimate has to be created.
• The lay-up doesn't reflect usual cutting observe, i.e. vamps tend to be cut along from the butt and backbone areas, quarters from belly, legs, neck space etc.