Blur effect

By default, Realsoft 3D's render engine computes razor sharp images. Sometimes it is desirable to produce 'smoother' images - to obtain a certain image style or perhaps to reduce antialiasing problems. Smoothing is a quick way to improve quality when only a low level of actual ray tracing antialiasing can be used (for speed reasons etc.).

The 'Blur' effect is a useful tool in this situation. The fact that blur can be applied selectively greatly enhances the usability of the effect.

Tutorial level: Medium

Example project: 'tutorprojects/postprocessing/selectiveblur'   
   
 
1. The first step is to model a simple test scene. For example, create a large floor plane using the rectangle tool and place some test objects above it. Texture map the floor and take a suitable view to the scene so that texture pattern gets dense in the horizon. Then ray trace the view.  

A simple test scene for the blur effect   

2. Go to the Post Image Effects tab of the Select window. Select 'New/Blur' from the popup menu. Then drag and drop the new effect that appeared to the end of the effects list to the view window. This inserts the effect to the current effect configuration. Render to see how the blur effect changes the image. 

Blur with default settings added to the image   

3. Select the blur effect and open the property window. By default, the blur effect used the minimal amount of blur (level 1, iterations 1). The blur was applied uniformly to all parts of the image.  

The default blur settings 

Let's experiment with selective blurring. For example, we may try applying the blur only to those parts of the image, which are covered by the floor pattern. Other (foreground) objects remain sharp. 

4. Switch to the 'User definded custom Channels' tab of the select window. Select 'New/Float' from the popup menu. Rename the created channel object as 'blur_on'. 

5. Go to the Geometric Objects tab of the select window and select the floor object. On the property window, select the second 'Col' tab. Then select 'blur_on' from the 'Surface Properties/Attribute' list. Define the value 1.0 to the attribute value field.  

6. Now switch back to the Post Image Effects tab of the Select window. Make sure that the blur effect is selected, and select 'blur_on' to the 'Threshold Channel' gadget of the property window. Define a 'Threshold' value of 0.999. You may also increase the 'Blur Level'and 'Iterations' values a bit.  

Settings for selective blur  

7. Render the view again. Now the floor is strongly blurred, whereas the foreground objects remain fully sharp.  

 
Selective blurring