2008
unit that 3ds Max uses for its calculations. The Display Unit is just a tool that
lets you customize how units are displayed in the user interface.
The following two scenarios show how to set unit scales after importing
geometry that has been created using different units than what is currently
set in 3ds Max:
Example 1: You import a table that was created in AutoCAD using metric
scale. The table is 9 units long, which corresponds to an actual length of 90
centimeters. When the table is imported into 3ds Max, it will measure 9 scene
units. Therefore, in the Units Setup dialog, you must set Scene Unit Scale to
1 Unit=10 centimeters. Your table is now the correct units because it is 90
centimeters long in 3ds Max model.
Example 2: You have an AutoCAD model that was created using Architectural
Units. The model is a room measuring 20’-4” long. In AutoCAD, Architectural
Units are stored as inches. Therefore, before importing the model to 3ds Max,
make sure to set the Scene Unit Scale to 1 Unit=1 inch. Once imported to 3ds
Max, the room will measure 244 units long (20’*12+4”).
TIP Use the Measure Distance tool on page 2529 to quickly check dimensions in
3ds Max.
Physically Based Workflow
Use
radiosity on page 5976 to create physically based lighting simulations.
When doing so, keep in mind the following:
■ Scene dimensions: Make sure your scenes are accurately dimensioned, with
consistent units (a light bulb in a room 120 meters high would look a lot
different than it would in a room 120 inches high).
■ Lights: You should work exclusively with
Photometric lights on page 4951
. You should also make sure that the light intensities are within a normal
range.
■ Natural Lighting: To simulate natural light, you should only use IES sun
on page 4969 and IES Sky on page 4973 . These provide accurate photometric
representations of sunlight and skylight based on a specified location, date
and time.
■ Material Reflectance: You should ensure that the materials you use in your
scene have a
reflectance value on page 5228 within the range of the physical
materials they represent. For example, a painted white wall should have
a maximum reflectance of approximately 80%; however, a pure white color
5990 | Chapter 18 Rendering