In this section, you work with IPR (Interactive Photorealistic Rendering) for mental ray rendering.

The advantage of rendering with IPR is that, after you render an image, you can adjust the shading and lighting attributes of the scene and then quickly update part or all of the rendered image to review the effect of your changes. IPR is useful for iterations when you need to fine-tune specific attributes. Updates to the image are not always instantaneous, but they are full quality.

To render the scene using IPR

1. In the perspective view, select View > Camera Attribute Editor to display the attributes for the camera.

   You need to specify the exact region of the perspective view you want to render.

2. In the Attribute Editor, open the Display Options section and turn on Display Resolution.

   A dark green rectangular border shows the region to be rendered. This region defines the area of the final image, and allows you to decide what appears or does not appear in the final image. (The left and right borders of the rectangle may be positioned at the edge of the window.)

   

3. Select Render > IPR Render Current Frame (or select the IPR render current frame button on the Status Line).

   The Render View appears as follows.

   

   The message displayed at the bottom of the IPR Render View window states “Select a region to begin tuning”. In the next step, you create a subregion of the image to render using IPR.

4. In the Render View, select View > Frame Image to resize the Render View window so it fits closely to the rendered image.

To select a subregion to render using IPR

1. In the Render View, drag a selection box around the small area surrounding the apple, counter, and wall as shown:

   

   When using IPR, this selected region updates as you alter any shading, texture, or lighting attributes. Selecting a smaller region quickens the update. You can select regions throughout the image to see those areas update.

2. In the scene view, right-click the wall and select Material Attributes to display the Attribute Editor for the Lambert shader you applied to the wall.
3. Click the Color box and change the color to green.

   The area within the selected region of the Render View updates immediately as you alter the color; the wall turns green.

   When you drag within the color wheel of the Color Chooser window, the selected region updates occur immediately.

   

   NoteIf the region does not update, in the Render Settings window, turn the Raytracing option off.

   (You won’t alter any other attributes in this lesson. The purpose of the lesson is to learn the process of rendering, not to perfect the results at this point.)

So far, you’ve used IPR to see changes you made to a shader. If you add lights to the scene rather than using default lighting, you can also use IPR to help adjust the lighting.