Translucency

A translucent material transmits light, but unlike a transparent material, it also scatters the light so those objects behind the material cannot be seen clearly.

You can use translucency to simulate frosted and etched glass.

Translucent Material

Designed for radiosity

Do not use with shadow maps: use with ray trace shadows

If you use radiosity, it will process light transmitted by translucency. The accuracy of this depends on the mesh: the more subdivided the faces are, the more accurate the solution will be (at a cost of processing time).

Diffuse Black

Translucency Brite blue

Most close to accurate with thin materials

Specular levels

0%, no highlight

Over 100%, overloaded

To select a good translucency [or filter] color

Ramp up the HSV, especially the Value

Filter Color

You can use the filter color with volumetric lighting to create effects such as colored light through a stained-glass window.

The “glass” object on the left has a multi-sub of 3 completely transparent translucent materials, with red, blue, and green filter colors. The light source has ray trace shadows on, resulting in the colored shadow upon the walls.

Opacity setting

This works best if opacity is set to 50%

Use the right shadow type

With area shadows the shadow has no color:

Ray-traced shadows cast by transparent objects are tinted with the filter color and have the effect we are after:

Place a bitmap in filter color:

With the procedural cell shader, set to high HSV colors, fractal:

Add volume fog to the light, and set the projector map to the same procedural map or bitmap as used in the translucent material, and the material appears as colored volumetric light:

Here we are at 100% opaque translucent material

Diffuse: Blue

Translucent color: Green

This has no opacity.
The blue diffuse disappears.
We only see the translucent color, green.
Specularity is set to 0%, so we see none of the filter color red.

Turning up the specularity,

we see the filter color red.

Translucent plastic

Backside Specular ON

highlights on both sides

Backside ON

Frosted glass

reflective on one side only

Backside Specular OFF

highlights on only one side.

add a fine-grained bump map

Backside OFF, plus with noise bump

Raytrace material special effects rollout

Translucency—Creates a translucent effect. The Translucency color is a non-directional diffuse reflection. The diffuse color on an object depends upon the angle between the surface normal and the position of the light source. By ignoring the surface normal alignment, this color component simulates translucent materials.

For thin objects, the appearance can be like shining a light on the back of a piece of rice paper. You can cast shadows onto the back of the paper and see them projected through the paper; this works well with a projector light. On thicker objects, you can get some good wax-like effects.

This is the default raytrace with a blue in translucency:

Same material with radiosity:

For thin objects, the appearance can be like shining a light on the back of a piece of rice paper. You can cast shadows onto the back of the paper and see them projected through the paper; this works well with a projector light. On thicker objects, you can get some good wax-like effects.

50% opacity, the light of course has ray trace shadow.

You will have to adjust colors to get it to work on the other side:

Falloff map
Default falloff settings in the diffuse slot creates the appearance of translucency:

LumeTools Translucency shader

Often in the real world objects receive light from their back side:

• a paper held up to a light,
• a lamp shade, light bulbs,
• frosted or stained glass,
• sun-dappled tree leaves, etc.

Translucency models this effect, letting light that originates behind a surface bleed through to the front.