When rendering an image with any rendering program, including V-Ray for SketchUp, you must understand three main factors that will affect the image: Lighting, Materials, and Mapping. Lighting plays the most important role among these three. It will affect the color, shadow, reflection and refraction among every single object in the scene.
V-Ray for SketchUp is a rendering engine equipped with Global Illumination (GI), which helps the users setup the lighting for entire scene easily. So they don't have to spend a lot of time adjusting lighting location and brightness. The concept of GI is very simple. Imagine a room has a window but no light in it. The natural light from the outside of the room comes in through the window so the room doesn't look completely dark even though there is no light in it. Some people even call this the "lazy boy lighting". Its purpose is allowing the users to have the most natural light possible without spending too much time to achieve it.
V-Ray for SketchUp also supports High Dynamic Range values, also called HDRI (High Dynamic Range Image). With a normal 24bit, 8bit per channel RGB image (Low Dynamic Range Image), the brightest white color you can get is R255, G255 and B255. But this is still thousands times lower than what the sun light can produce. With the HDR file format, users can have more control ranging from dark to bright. The HDR is a very special image file format. It usually starts with professional 360 degree photography, then transforms to 96bit full scene image by using professional HDR software. The benefit of using HDR is that you can use this full scene image as your render light source. It also can be used as the background rendering.
V-Ray for SketchUp also supports regular image file formats as a light source for GI. However, it is still limited compared to using an HDR image format to describe the lighting environment. Together with other regular image file format simulated lighting environments, it is usually used only as supporting lighting for the entire scene. That means adjusting the setting of major light sources is still a very important work in V-Ray for SketchUp. We will discuss more about how to use lighting, materials and mapping later.
