About Setting Draft Scale
By setting a draft scale using the Detail option draft_scale, you can create draft entities with a scaled size. If you set it at 0.5, any entities that you create subsequently are one-half the size that you specified. For example, creating a horizontal line of 4 inches (by selecting one endpoint and placing the second endpoint using Rel Coords with x=4 and y=0), the line measures as 2 inches on paper, but dimensions as 4 inches. If you change the draft scale after creating and associatively dimensioning draft entities, the dimensions change.
The draft scale, like other parameter values in the Detail option, is completely independent of a drawing scale. When the drawing size changes, the value of the draft scale does not change. The system scales the draft geometry by the proportion necessary to maintain its relative location on the sheet, and it appears to be the same size that it was before. The geometry is, in fact, a different size (because the sheet is a different size), and this is reflected by any new dimensions that you create for it; the ratio of the new dimension to the previous one is equal to the ratio of the size of the new sheet to the old one. If you set the Detail option associative_dimensioning to yes (the default), when the size of dimensioned draft entities changes, the system updates the dimensions to the latest value ).