Abstract
Geometric modeling provides graphic representations of real or abstract objects. Realistic representation requires three dimensional (3D) attributes since natural objects have three principal dimensions. CAD software gives the user the ability to construct realistic 3D models of objects, but often prints of these models must be generated on two dimensional (2D) standardsized sheets. The transformation of 3D objects into 2D representations on standard-sized sheets requires one to use a proportional relationship called a scale, which is defined by a scale factor (SF).
 Two mathematical models for a scale factor, one for reduction scaling and the other for enlargement scaling, are presented for standard orthographic views. The models are based on the sizes of standard drawing sheets and the principal dimensions of the object. The application of the models is demonstrated with two illustrative examples, one for reduction scaling and another for enlargement scaling. The scale factors selected on the basis of the models were used to prepare detail drawings for the examples. In each case, the scale factor appeared satisfactory.
 It is shown that the models are tolerant of error in the only parameter that is assumed when applying them, suggesting that they are robust. This robust feature is an advantage, because in real design drafting situations, one must often make assumptions about sizes. The models can thus accommodate some erroneous assumptions.
Highlights
In a drawing context, scale refers to the proportional relationship between an image size on a drawing media and the design size
A proportion is expressed as a ratio, and a drawing scale factor (Duggai, 2000; Madsen et al, 2002) is the ratio of proportion between a design size and the plot size
The plot size is the actual size of an image on a standard drawing sheet at printing or plotting time
Summary
Scale refers to the proportional relationship between an image size on a drawing media (or plot size) and the design size. A scale factor will depend on the design size, the level of detail information associated with the drawing views, and the sheet size chosen for plotting the drawing (Madsen et al, 2002). When the model space object is modified, the view in paper space can be updated These 2D views can be annotated with dimensions and notes on electronic standard sheets, standard orthographic or multiview drawings. The selection dimensions completely determine the views of a plot scale factor is one of the space requirement. This is important because important skills design drafters must acquire there is no need to worry about the complexity (Madsen et al, 2002). Hm = full size model height requirement for views sheets, it is possible to evaluate before creatand annotations ing drawings. With SF as the scale factor for a drawing task, for: Model Application The application of the scale factor model involved three main tasks of modeling two com-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
