VRay for SketchUp Manual
Chairs-Emissive-Original.skp and we are going
to show you how to create a self-illuminated material. Select the green chair on
the right. Select "Materials Editor" icon over V-Ray toolbar to open the
Material editor dialog box.
Add Emissive Layer
1. Click on the + next to the Chair_Green
to pull down the layers. Right click on Emissive Layers and select Add new
layer. You will see the new Emissive layer added to the right side.
Open the Emissive menu. Default set the color to white, intensity to 1 and
Transparency color to black. Click on Material Preview and you will see a
completely white material ball. Render it and you will get the image like the
one on the bottom.
Self-illuminated material can make the object become a lightsource itself. It
does not limit to a certain shape like a regular light type does. Every part of
the object can be illuminated and used as a lightsource.
Self-illuminated material is perfect to create objects like: light ball,
light tube, light shade, stylish lighting, cold light and lit screen. However,
emissive materials should not be used as the primary lighting for a scene.
|If you are using a physical camera in your
scene, you may notice that your light emitting materials render black or
darker than expected. This is because the physical camera reacts
differently to light than a regular camera does. Because of this you may
have to make your light emitting materials significantly brighter in
order to be rendered by the physical camera.
Adjust the Intensity
Default set the Intensity to 1. Below images are rendered with Intensity of 3
(left) and 5 (right).
Adjust the color
Default set the color to white. Click on the color box to change to a
different color. Notice that if the setting of the Intensity is too high, the
color of the object itself will become close to white. Only the light come out
from this self-illuminated object will carry the correct color. So we recommend
you not to use this as a normal lightsource. Just make it as a decorative object
in the scene.
Please refer to below image chart for results of various Emissive
Intensities. By controlling the degree of Transparency under the Emissive Color,
you can still keep the diffuse color of the object. For example, when the
Intensity is higher than 2, the diffuse color is washed out and become white.
To avoid the self-illuminated object become white, please also refer to
the Color Mapping.
Except using colors as light source for the self-illuminated materials, you
can also use texture map directly as light source.
1. Click on the "m" to the right of the
Color under Emissive control panel.
2. The Texture Editor will then open up.
Select Bitmap from Type's pull down menu and you will see the control panel show
up to the right.
3. Under Bitmap, click on the "m" to the
right of the file and pick a bitmap to use as the light source.
4. After the bitmap is selected, the "m"
now becomes "M". Click on the Update button to preview the bitmap. Click on
Apply and you can use this bitmap as the light source.
5. Click on Update Preview and you will
see the Bitmap is now on the material ball. Render it and you will get the
result as the image on the bottom.
Please note that if any type of map is being used in Texture Editor, the
Color and Intensity under Emissive will no longer function. You can't use these
two options to control the brightness of the material any more. You need to
click on the "M" and go back to the Texture Editor and adjust brightness there.
All other control options in the Texture Editor work the same like this.
Click on the "M" and go back to the Texture Editor window. Please pay special
attention to below options as these options are often used for controlling the
Bitmap texture map.
Multiplier: Controls the intensity of the Bitmap. Default set to 1.
Increase this number will intensify the color tone, brightness and color
contrast. Preview will not show much of difference if the value is too small.
Blur under Bitmap: Control the blurriness of the Bitmap. Default set
to 0.15. Set to 0 will not have any blur effect to the Bitmap.
Override under Bitmap: Adjust the Gamma value of the Bitmap. Increase
the value will make the Bitmap brighter. This parameter is also important for
Tile: Repeat the Bitmap texture on the object. Default set to
selected. When uncheck the Tile, you will see only one Bitmap texture on the
UVW Repeat: Controls how many times a map is repeated within a given
space (either within the surface, or within mappings)
UVW Rotation: Adjust the degree of rotation of the Bitmap
The darker environment lighting will not affect the Bitmap setting for
self-illuminated material (ipod image). The Bitmap will still render as its own
setting for brightness. Use the same way to create cold light effect. Also shown below are two other examples.