In Unit 7 students enhance their basic knowledge of technical drawing representations learned earlier in the course to include the creation of alternate (section and auxiliary) views and appropriate dimensioning and annotation of technical drawings. Students are also introduced to the reality of variation in dimensional properties of manufactured products. They learn the appropriate use of dimensional tolerances and alternate dimensioning methods to specify acceptable ranges of the physical properties to meet design criteria. Students apply this knowledge to create working engineering drawings that document measurements collected during a reverse engineering process. These skills also allow students to effectively document a proposed new design. Students use 3-D computer-modeling software to model the assembly of the consumer product, because such a model can be used to replicate functional operation and provide virtual testing of product design. Source: PLTW