6.0

Applying Dimension Constraints | 95
In this case, the height of the sketch must maintain the same proportion to
the length, even if you change dimensions later. In an equation, you can
state the height relative to the length. The dimension for the vertical line is
defined as an equation of d1 = d0/.875 where d1 is the parameter name for
the vertical line and d0 is the parameter name for one of the horizontal lines.
The d variables in the equations are parameter names assigned by Mechanical
Desktop when you define the parameters. The letter d indicates that the
parameter is a dimension. The number signifies the dimension number rela-
tive to the beginning of the dimensioning sequence.
Open the file sketch6.dwg in the desktop\tutorial folder. Add and modify
dimensions to complete the definition of the following sketch.
NOTE Back up the tutorial drawing files so you still have the original files if you
make a mistake. See “Backing up Tutorial Drawing Files” on page 40.
The before-and-after sketches reveal where dimensions are needed and in
what order you should place them. The dimensions needed here have
already been identified and are expressed as numeric constants.
To keep the sketch shape from becoming distorted as the dimensions resize
it, define larger dimensions first: the left vertical line (dim 1) and the bottom
horizontal line (dim 2).
By adding geometric constraints, you can reduce the number of dimensions
you need. Later, you can modify the sketch with fewer changes.
After the basic shape has been defined, you replace the rightmost vertical line
and the top horizontal line with fillets, and add geometric constraints and
dimensions to finish the profile.
dim 1
dim 2
dim 5
dim 4
original sketch profiled sketch
dim 3