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1321

1312 Chapter 15: Lights and Cameras

IE S S ky Light (Photometr i c)

Create panel > Systems > Create a Daylig ht system in

your scene. > Modify panel > Daylight Parameters rollout

> Skylight > IES Sky

Create panel > Lights > Photometric > IES Sk y

Create menu > Lights > Photometric > IES Sky

IES Sky is a physically-based light object that

simulates atmospheric effects on skylight (page

3–1012).

Outdoor scene lit by the IES sky light

Note: (IES stands for Illuminating Engineering

Society; see IES Standard File Format (page

2–1328).)

Yo u c a n c r e a t e d a y l i g h t l i g h t s m a n u a l l y, b u t

to get the b est results, you should use them in

conjunction with the Daylight system (page 1–418).

The Daylight system combines the two daylight

componen ts of sun and sky in a unified interface.

It allows you to set date and time positions with

the light type you want to use.

IES Sky works correctly only when the sky object

is pointing down from the Z axis, meaning that it

points down w hen looking from the Top view.

When using the default scanline renderer, IES Sky

produces the best results when used in conjunction

with one of the advanced lighting options (page

3–44):radiosityorlighttracing.

Wa rn in g : When you render with the mental ray renderer

(page 3–78), o bjects illuminated by IES Sky appear dark

unless you turn on Final Gathering (page 3–940).The

toggle for Final Gathering is on the Final Gather rollout

(page 3–111) of the Render Scene dialog.

When you add an IES Sky light, 3ds Max

automatically assigns a Look At controller (page

2–344) to it, with the light’s target object assigned

as the Look At target. You can use the controller

settings on the Motion panel to assign any other

object in the scene as the Look At target.

Using R ender Elements with an IES Sk y

Light

If you use Render Elements (page 3–130) to output

the lighting element (page 3–141) of an IES Sky

light in a scene using either radiosity or the light

tracer, you cannot separate the direct, indirect, and

shadowchannelsofthelight.Allthreeelements

of the IES Sky lighting are output to the Indirect

Light channel.