8

104 Chapter 17: Rendering
Enable
When on, the mental ray renderer
calculates
depth-of-field (page 3–89)
effects when
rendering a Perspective view. Default=off.
Met hod dr op-down l i st Selects either f-Stop, for
controlling depth-of field by an f-Stop parameter,
or In Focus Limits, by selecting Near and Far
limits. Default=f-Stop.
In most cases, the f-Stop m ethod is easier to use.
TheInFocusLimitsmethodcanhelpwhenthe
scale of objects in the scene makes it hard to
control depth of field using the f-Stop value alone.
Focus PlaneFor Perspective viewports, sets
thedistancefromthecamera,in3dsMax
units, at which the scene is completely in focus.
Default=100.0.
For Camera viewports, the focu s plane is set by the
camera’s target distance.
f-StopWhen f-Stop is the active method, sets the
f-stop for use when you render Perspective views.
Increasing the f-stop value broadens the depth of
field, and decreasing the f-stop value narrows the
depth of field. Default=1.0.
The f-Stop c an have a value less than 1.0. This is
not realistic in terms of an actual camera, but it
can help you adjust the depth of field for scenes
whose scale does not use realistic units.
Near and Far WhenInFocusLimitsistheactive
method, these values set the range, in 3ds Max
units, within which objects are in focus. Objects
lose focus when they are closer than the Near value
or farther than the Far va lue. These values are
approximate, because the transition from in-focus
to out-of-focus is gradual, not abrupt.
TheNearandFarvaluesarerelatedtoeachother
and to the value of Focus Plane. Changing the
valueofNearchangesFaraswell,andviceversa.
Specifically, if
H = Hyperfocal distance, the Focus Plane value at
which the Far limit becomes infinity
D=TheFocusPlanedistance
D
n
= The Near distance
D
f
=TheFardistance
Then
D
n
=HD/(H+D)
D
f
=HD/(H D)
Ca ustics and Global Illumination
Rollout (mental ray Renderer)
Rendering menu > Render > Render Scene dialog
> Indirect Illumination panel > Caustics and Global
Illumination rollout
Main toolbar > Render Scene > Render Scene dialog
> Indirect Illumination panel > Caustics and Global
Illumination rollout
Note: The Indirect Illumination panel appears only when
the mental ray renderer is the currently active renderer.
The controls in this rollout are for the effects of
caustics (page 3–91)
and
global illumination (page
3–92)
.
Procedures
To r ender with caustics:
1.
Select each object you want to generate caustics,
either by reflection or refraction. Right-click
and choose Properties, then on the mental ray
panel of the Object Properties dialog, turn on
Generate Caustics.
Objects receive caustics by default. If you think
this value might have changed for the objects
you want to receive caustics, u se those objects