Show in Contents

Add to Favorites

Home: Autodesk Maya Online Help
 
 Open the scene for the lesson

Lesson 5: Caustics

Render the scene using caustics
 
                
               
             
             
            
            Render the scene using
                  raytracing
          
       
       
       
       
      To better understand
         the differences between caustics versus other lighting, you begin
         by rendering the scene using the mental ray for Maya renderer without
         using Caustics.
      
      You start by preparing
         the scene and then rendering. In this section you:
      
      
         - Set a panel layout for rendering
         
- Turn on shadows for the spotlight
         
- Turn on the mental ray for Maya renderer
         
- Set the image size for your rendering
         
- Set the image quality preset
         
- Render the image using raytracing
         
Setting a panel layout
            for rendering
         
         Producing a rendered
            image usually requires that you render test images to achieve the
            final result. This may involve adjusting many render quality, shading,
            and lighting settings. Opening and closing the various windows can become
            tedious.
         
         Keeping the most frequently
            used windows and panels open allows you to work more efficiently.
         
         In the following steps,
            you select a panel layout to work more efficiently with the various
            panels and windows.
         
         To set a panel layout for rendering
         
         
            - From the perspective view’s panel menu,
               select Panels > Saved Layouts > Hypershade/Render/Persp.
               The
                  panel layouts update to display the Hypershade window, Render
                     View window, and Perspective view
                  simultaneously.
                When you render an image,
                  it appears in the Render View window.
                TipYou can resize the
                     panels in a preset layout by dragging the border between neighboring
                     panels using your left mouse button.
                   
Turning on shadows
         
         In this lesson, you learn
            how the bottle’s shadow can be made to appear more realistic as
            a result of the caustics.
         
         To turn on shadows for the spotlight
         
         
            - In the Hypershade window,
               click the Lights tab.
               The Hypershade displays
                  icons for the two lights in the scene.
                
- In the Hypershade window,
               double-click the icon for spotLightShape1.
               The Attribute
                     Editor appears.
                
- In the Attribute Editor,
               click the spotLightShape1 tab to display the lighting attributes
               for the spotlight.
            
- In
               the Shadows section, open the Raytrace
                  Shadow Attributes and turn on Use RayTrace Shadows.
               When you render the scene,
                  shadows are cast by the spotlight.
                
- Hide the Attribute Editor by
               clicking the Show/Hide Attribute Editor icon on
               the Status Line.
            
Using the mental ray for
            Maya renderer
         
         To
            use the Caustics feature in Maya you must render using the mental
            ray for Maya renderer.
         
         To turn on the mental ray for Maya renderer
         
         
            - In the main menu, select 
                        Window > Rendering Editors > Render Settings (or
               click the Render Settings icon in the Render
                  View window).
            
- In the Render Settings window,
               set the Render Using setting to mental ray.
            
Setting the image size
            for rendering
         
         You set the size that
            an image will be rendered in the Render Settings window.
            For this lesson, you render the image at a size that allows you
            to evaluate the caustic effect.
         
         To set the image size for rendering
         
         
            - At the top of the Render
                  Settings window, select the Common tab
               and open the Image Size settings.
            
- Choose
               the 640 X 480 preset from the Presets drop-down
               list.
            
Setting render presets
            for raytracing
         
         For the first rendering,
            you render the scene to see how the shadows appear without using
            caustics.
         
         To set Render options for raytracing
         
         
            - In the Render Settings window,
               select the Quality tab and set the Quality Presets setting
               to Production.
               The Production preset
                  ensures that the refraction level settings (found in Raytracing
                     Quality section) are at a level high enough to render
                  objects with translucency (for example, the bottle). The Production preset
                  also sets the anti-aliasing level for the image.
                
- Close the Render Settings Window.
            
Rendering the image
         
         When you render an image,
            all of the objects, lighting, shading materials, and image quality
            settings are used to calculate the image, from the camera’s view.
         
         To render an image using mental ray for
            Maya
         
         
            - Click in the perspective window to indicate
               which view you want to render.
            
- In the Render View window,
               click the Render Current Frame icon.
               The bottle scene renders
                  using the mental ray for Maya renderer and the image appears in
                  the Render View window.
                .TipIf the rendered image
                     appears either too small or too large in the Render View window,
                     select View > Frame Image from
                     the Render View menu to fit the
                     image to the Render View.
                   
- Once
               the render is complete, click the Keep Image icon
               in the Render View window.
               Keeping the image allows
                  you to compare it to any subsequent test renders. In this lesson
                  you compare each successive rendered image to the previous one to
                  observe how the changes you make to render settings affect the rendered
                  image.
                The rendered image shows
                  the following:
                
                  - A translucent bottle with apples beside
                     it casting shadows towards the rear of the scene. Notice how the
                     shadows appear when raytrace rendered.
                  
- The distortion of the table surface in
                     the translucent glass effect based on the refractions and reflections.
                  
- A dark region on the surface of the bottle.
                     This results from the bottle reflecting the empty black area of
                     the scene in front of it.
                  
 
In the next section,
            you turn on the caustics rendering attributes and render the scene.