Difference between revisions of "CAD:Units"

Latest revision as of 16:35, 24 December 2010

Description

The base unit of measure in the CAD system is the Drawing Unit. This an arbitrary unit of measure that is used by the draftsman while drawing. The draftsman does not explicitly set the Drawing Unit to equal an actual unit of measure but rather tells the reader of the document what unit he has employed.

For example, say that you are drawing a house in North America. You may use 1 Drawing Unit = 1 Inch. In which case 12 DU = 1 Foot. You would need to let the reader of the document know that 1 DU = 1 Inch.

The CAD system can be set up to format the display of the number system in a number of different ways. You have control over the display format and the display precision. The numeric system of the computer uses the Float data type that can be accurate to 27 decimal places. This may be too precise. We probably don't need to display all 27 decimal places but can reduce our precision to 2 to 4 decimal places for most applications.

You can specify the type of the current unit of measurement and the precision for the current units as also the current angle format and the precision for the current angle display.

Remarks

Type of measurement can be:

*  Scientific        1.6449E+001
*  Decimal          16.4492
*  Engineering      1' - 4.4492"
*  Architectural    1' - 4  7/16"
*  Fractional       16 7/16
*  Windows desktop (It takes the settings of the regional settings)

Angle format can be:

* Decimal degrees
* Degrees/minutes/seconds
* Gradians
* Radians

You can also set linear and angular precision