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VRay for SketchUp Manual
Transparency Mapping
What is
Transparency Mapping?
Transparency mapping is another method using Bitmap to create materials. The
difference is that this is using an alpha channel to get rid of unwanted part of
the Bitmap, saving only the part covered by alpha channel. This is called a
mask.
This is used mostly for creating product logos, stickers and numbers. Many
users try to avoid using transparency mapping and model the actual object in the
scene. Although you can ignore material settings by creating the actual model of
objects, that will increase both the number of objects in the scene and the file
size. The more objects you get, the longer the rendering time you would need.
You will get the result as the image below if you apply the texture map
directly without transparency map. The black background of the texture map is
blocking part of the block. The image on the bottom is rendered with transparency map.
Here is the object and the transparency map that we will use to create our
label.
You will get the result as the image below if you apply the texture map
directly without transparency map. The black background of the texture map is
blocking part of the box . The image on the bottom is rendered with transparency map.
1. Open Block-Red.skp
select the block and open its Material Editor. Select "Block-RedMap", right
click on Diffuse Layer to add new layer and you will have the dialog window as
the image on the bottom. Change its diffuse color to red (R-244, G-40, B-11).
2. Select the first diffuse layer and
click on the "m" at the right to enter the "Texture Editor". Load the bitmap you
wish use for diffuse texture map.
Use Photoshop, PhotoImpact and similar image editing software to create
black and white image and save as .bmp, .jpg or .png which are the formats
accepted by V-Ray.
3. Click on the "m" at the right of
"Transparency" and load the bitmap you wish use for transparency map on the
"Common" properties enable "invert" to invert the bitmap.
Render it and you will get an image like the example below. the transparency
map is covering the entire block.
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