Autodesk 507B1-90A211-1301 User Guide - Page 329

■ Use a solid color shader set as density shader for simulation of density variations in the medium. ■ Decrease the Error Bound parameter, if image appears spotty outside shadow areas. ■ Increase the Min LOD parameter, if areas with volumetric shadows appear spotty. ■ For fast previews, set the Error Bound parameter high, and the Min LOD parameter small. ■ For best results, set the Fall Off option to Inverse Square Law, and turn on Auto Exposure. Image-based Lighting Image-based lighting, simply put, is where an image is used to light a scene. In the real world, every object is lit not only by light sources like the sun, lamps etc., but also by everything around. Standing in the middle of a street, a person will be lit by the sun, the blue sky, the brown buildings and the grey floor. Emulating this form of lighting clearly has the potential to create incredibly realistic images. Images used in this lighting method are a special kind of image, called a High Dynamic Range Image or HDRI. This type of image has the capability of lighting a scene with incredible accuracy. In Presenter, an HDRI is wrapped around the scene as a sphere, and color and brightness from the HDRI are cast onto the 3D model to light it. A model lit with normal lights The same model lit with image-based lighting You can see the difference this form of lighting can make to rendered images. And the enormous advantage here is that it is much easier to set up than traditional lighting. To set up image-based lighting 1 Open the Presenter window, and click the Lighting tab. 2 Click the Recommended folder in the left-hand pane of the Lighting tab. Advanced Lighting | 317