bạn nên có một khóa điều khiển đã được tạo ra cho các đối tượng mục tiêu. Tiếp tục với cảnh từ phần trước, hoặc mở một scene Để xem một phiên bản của cảnh đến thời điểm này, mở cảnh từ thư mục chapter5 cảnh \ trên đĩa DVD. | 496 chapter 9 lighting with mental ray Figure The image on the left is rendered without Caustics enabled the image on the right has Caustics enabled. 18. The Caustics settings are similar to the Global Illumination settings. In the spotlight s Attribute Editor lower Photon Intensity to 3000. Set Caustic Photons to 80000. You can adjust the color of the caustic highlight by changing the caustic photon color or by changing the color of the transparency on the crystal shader. It s probably a better idea to change the transparency color on the shader that way if one light is creating Caustics on two different objects that are shaded with different colors the color of the caustic photons won t clash with the color of the objects. The Exponent setting for Caustics works just like the Exponent setting for Global Illumination. 19. Select the crystal object and open the Attribute Editor. 20. Click the Crystal Shade tab. Set the Transparency color to a light pink. 21. Open the Render Settings window and click the Indirect Lighting tab. Set Accuracy of the Caustics to 32. 22. Create a test render of the scene Figure . FIGURE The scene is rendered after lowering the Accuracy and the Photon Intensity settings. indirect lighting global illumination 497 A lower Accuracy value produces sharper caustic highlights at the risk of some graininess. A higher value removes the grainy quality but softens the look of the caustics. You can also soften the look a little by setting Filter to Cone. The Radius value can be left at 0 if you want Maya to determine the proper radius at render time. Settings less than 1 make individual photons more visible. The Merge Distance setting merges all photons within the specified distance which can decrease render times but remove the detail in the caustic patterns. Caustic Light Setup In practice spotlights are usually the best choice for creating Caustics. Area lights don t work nearly as well. The cone angle of the spotlight is reduced .
