The Skylight light models
daylight. It is meant for use with the
Tracer. You can set the color of the sky
or assign it a map. The sky is modeled as a dome above the scene.
Model rendered with
a single skylight, and light tracing
When you render with
scanline renderer, Skylight works best with
advanced lighting: either the Light Tracer, or
A skylight is modeled
as a dome above the scene.
TipThere are several
ways to model daylight in 3ds Max Design, but if you use the Light Tracer,
a Skylight often gives the best results.
If you encounter
visual anomalies when rendering a bump-mapped material with a Skylight,
convert the material to an
Lighting Override material
and then reduce
the Indirect Light Bump Scale value.
Using a Map with the Skylight
If you use a map with
a Skylight, the following guidelines can improve its effect:
- Make sure that the mapping coordinates
are spherical or cylindrical.
- For light tracing, make sure you use
sufficient samples. A good rule of thumb is to use at least 1,000
samples: set Initial Sample Spacing to 8x8 or 4x4, and increase
the value of Filter Size to 2.0.
- Use an image-processing application to
blur the map before you use it. With a blurred map, you can use
fewer samples to obtain good results. When used with Skylight, a
blurred map will still render well.
Be aware that using sufficient
samples with a mapped Skylight will take longer to render than if
the light were not mapped.
Skylight and Radiosity
in Architectural Design
In order for radiosity
to be processed correctly when a Skylight is added to the scene,
you need to make sure that walls have closed corners and floors and
ceilings have thickness under and over the walls. In essence, your
3D model should be built just like the real-world structure is built.
If you build your model
with walls that meet along a single edge or floors and ceilings
are simple planes, when you process radiosity after adding a Skylight, you
can end up with “light leaks” along those edges.
Some of the ways to repair
a model so light leaks do not occur are as follows:
- Make sure floors and ceilings have thickness.
You can fix this by extruding those surfaces
at a sub-object level or by applying modifiers like
- Use the
command to create walls.
The Wall command is programmed to make sure
corners are constructed of solid objects instead of leaving a single,
- Ensure that floor and ceiling objects
extend beyond walls.
Floor objects need to extend under walls and
ceilings need to extend over walls.
By building your 3D model
using these guidelines, light leaks will not occur when you process
radiosity after adding a Skylight to the scene.
Using Render Elements with
If you use
Elements to output the
element of a skylight in a scene using
either radiosity or the light tracer, you cannot separate the direct, indirect,
and shadow channels of the light. All three elements of the skylight lighting
are output to the Indirect Light channel.
To create a Skylight:
- On the Create panel, click (Lights).
- Choose Standard from the drop-down list.
- On the Object Type rollout, click Skylight.
- Click a viewport.
The light is now part of the scene.
NoteThe position of the
Skylight, and its distance from objects, has no effect. The Skylight
object is simply a helper. Skylight always comes from “overhead.”
- Set the creation parameters.
Turns the light on and
off. When On is on, shading and rendering use the light to illuminate
the scene. When off, the light is not used in shading or rendering.
Amplifies the power of
the light by a positive or negative amount. For example, if you
2, the light will be twice as bright. Default=1.0.
Using this parameter
to increase intensity can cause colors to appear "burned out." It
can also generate colors not usable in videos. In general, leave
Multiplier set to its default of 1.0 except for special effects
and special cases.
Sky Color group
- Use Scene Environment
Colors the light using
the environment set up on the
This setting has no effect
unless light tracing is active.
- Sky Color
Click the color swatch
to display a
Color Selector and
choose a tint for the Skylight.
- Map controls
These let you use a map
to affect Skylight color. The button assigns a map, the toggle sets whether
the map is active, and the spinner sets the percentage of the map
to use (when the value is less than 100%, map colors are mixed with
the Sky Color).
For best results,
The map has no effect
unless light tracing is active.
NoteIf the renderer is
not set to Default Scanline, or if the Light Tracer is active, these
controls are disabled.
- Cast Shadows
Causes the skylight to
cast shadows. Default=off.
NoteThe Cast Shadows
toggle has no effect when using radiosity or the light tracer.
- Rays per Sample
The number of rays used
to calculate skylight falling on a given point in the scene. For animation,
you should set this to a high value to eliminate flickering. A value
of around 30 should eliminate flickering.
Increasing the number
of rays increases the quality of your image. However, it also increases
- Ray Bias
The closest distance
at which objects can cast shadows on a given point in the scene.
Setting this value to 0 can cause the point to cast shadows upon
itself, and setting it to a large value can prevent objects close
to a point from casting shadows on the point.