WBS+
(Web/Blender Studio+)
Blender Tutorial
Efficient way for DOF
Blender recalculate every time when node value is changed. This duration of recalculating will be longer if the scene is complex, many textures are assigned or OSA is set in high (there is other settings which makes the recalculating longer). It is one way that turn off "Use Nodes" button makes it shorter. But this page introduces another way, efficient way to add DOF with reduce the recalculating duration.
Note) This page is continuous page of the tutorial, "DOF(Depth of Field)".
Step 1. Save original scene.
Turn off the "Do Composite" button and render the scene. And then save the rendered image (filename : fig1.jpg). The image was created by previous tutorial, "DOF(Depth of Field)" .
Step 2. Reduce complex setting
(1) Copy whole this scene by select the Scene button at the top of the window. And select "ADD NEW" -> "Full Copy".
(2) Turn off or change to lower value which makes recalculation longer. For example, OSA setting to low, remove textures, sample of the area light to low or change to lamp light, etc.
The reason of this is that they are not necessary to make Black-White image of the DOF.
Step 3. Create base image for DOF.
(1) Disconnect the "Blur" node from the Node structure to be able to render Black-White image.
(2) Turn on "Do Composite" button and start rendering. Save the rendered image with name "fig2.jpg".
Step 4. Adding another scene
We create another scene for composite. Select "ADD NEW" -> "Empty" in the Scene menu at the top of window.(Note: You can use same scene for composition. This tutorial is just a sample. It depends on you).
Step 5. Loading images.
(1) Select "Space Key" -> "Input" -> "Image" to add "Image" node in the Node Editor.
(2) Press "Load New" button in the image node to load saved image, fig1.jpg. Repeat same procedure to load fig2.jpg.
Step 6. Reconstruction of DOF setting
Connect nodes from two "Image Node" to "Composite Node" as shown as below.
Step 7. Rendering.
Render the scene. It must be faster than before.
Step 8. Adjusting
The "ColorRamp" node is used for adjusting. The final image can be rendered without the "Color Ramp" node. But this node makes the image more adjustable. Of course, since the adjusting has a limitation, if you want to change more, you need to recreate the fig2.jpg and reload the image. Anyway as shown in the step 2, you removed complex settings which make a duration longer, recalculation will be shorter.