Creating Believable Materials - Photographic Rendering with V-Ray for SketchUp - page 210

The material we want to create for our walls is in most respects fairly simple and
straightforward in that it will consist of just three basic elements: a diffuse color, some
slight levels of reflectivity, and finally a bump map that will add some texture and also
help diffuse the reflections. However, things are not going to be quite as straightfor-
ward as we would like. You can see that we again need to use a bitmap in the bump
slot. Of course, without a bitmap applied in the diffuse slot, SketchUp doesn't assign
any kind of UV scaling to the geometry. This leaves us with no obvious means of
controlling the scale or size of our bump effect.
Now, in previous versions of V-Ray for SketchUp, we would have had to perform
a convoluted workaround in order to fool SketchUp into giving us what we need,
namely a UV map scale.
In V-Ray 2.0, however, we can simply make use of the new VRayBRDF layer.
To show how we can use this new tool to give us what we need here, let's perform
the following steps:
1. In the Diffuse rollout of our Walls material, click on the map button to bring
up the V-Ray texture editor.
2. From the map dropdown on the left, select the TexBitmap node.
3. In the Open Bitmap File pop up, navigate to your Exercise Files | Tex-
tures folder and select the Wall_Stucco_Bump.bmp file, click on open,
and then click on Ok to exit the V-Ray texture editor.
In order to easily see the map that we have just added, follow the next steps:
1. Click on the paint bucket tool to bring up the SketchUp material editor.
2. With the Walls material selected, enter a value of 200 (16 feet 8 inches) in
the horizontal parameter of the map scale controls in the Edit tab.
This scales up the map to quite an extent, which means that we can easily
see it in the SketchUp viewport. This tells us that it has definitely been ap-
plied to the wall geometry.
3. Set the map to a usable scale for our bump map by typing in a value of 15 (1
foot 3 inches) and closing the SketchUp material editor window.