1. A computer-implemented method of validating an application of geometric dimensioning and tolerancing (“GD&T”) in a drawing by using a drawing validation tool, the method comprising: operating a processor for executing software instructions stored in a computer readable memory, the software instructions defining a plurality of modules; validating, by the processor with a process module, a specification of geometric dimensioning and tolerancing with a set of geometric dimensioning and tolerancing rules; identifying, by the processor with an identification module, illegal specification of geometric dimensioning and tolerancing, wherein the illegal specification includes geometric dimensioning and tolerancing that does not satisfy the set of rules; producing, by the processor with a report module, a report that contains information regarding the illegal specification of geometric dimensioning and tolerancing; and providing, by the processor with an electronic user manual module, a correction instruction regarding the illegal specification of geometric dimension and tolerancing, the correction instruction referenced in the report.