9
850 Chapter 22: Customizing the User Interface
Display Unit Scale group
Choose a unit scale option (Metric, US Standard,
Custom, or G eneric Units) to activate its settings.
Metric—Choose this option and then choose a
metric unit: Millimeters, Centimeters, Meters, or
Kilometers
US Standa rd—Choose this option and then choose
a US Standard unit. If you choose a fractional
unit, the adjoining list activates to let you select the
fractional comp onent. The decimal units require
no additional specification.
TheUSStandardsareasfollows:
• Fractional Inches
• D ecimal Inches
•FractionalFeet
• D ecimal Feet
• Feet w/ Fractional Inches
• Feet w/ Decimal Inches
For the last two items, you can specify which unit
isassumedwhenyouenteravalueinanumeric
field and press
Enter without including a units
specifier, such as ’ for feet or " for inches.
For example, if Feet is the default, typing 5
followed by
Enter results in 5 feet. Typing 5"
followed by
Enter results in 0’5". If Inches is the
default, typing 5 followed by
Enter results in 0’5".
Typing 5’ followed by
Enter results in 5 feet.
Custom—Fill in the fields to define a custom unit
of measurement.
Gener ic Units—This is the default option (one
inch) and is equal to the system unit used by the
software.
Lighting Units g rou p
The Lighting Units group lets you choose
whether light values are displayed in Amer ican or
International units.
System Unit S etup Dia log
Customize > Units S etup > Click System Unit Setup.
This dialog appears when you click System Unit
Setup in the Units Setup dialog (page 3–848).
Wa rn in g : You should only change the system unit value
before imp orting or creating geometry. Do n ot change
the system unit in an existing scene.
Because of the nature of digital floating-point
calculations, distances that are extremely large
or extremely sm all can cause round-off error.
Symptoms of round-off error include trouble
navigating (zooming and panning become too fast
or too slow), unwanted viewport clipping, and
unexpected flipping of normals. Here are some
general guidelines to avoid these problems:
• Mak e sure your scene is roughly centered
around the origin (0,0,0).
Round-off error increases at large distances
from the origin.
• Makesurenosignificantdetailinthesceneis
smaller than one generic 3ds Max unit.
Note: The Rescale World Uni ts utility (page 2–53)
alters the scale of world units throughout the entire
scene, or selected objects.
Procedure
To change the sys tem unit:
1.
Choose Customize menu > Units Setup.
2. Click System Unit S etup.
3. Change the System Unit Scale value, and click
OK.
The system unit is immediately reset. Th is
setting remains in effect until you change it.