If you are starting this tutorial here, you will need the result of the previous section.
To add a macro feel to the image we will add a little bit of depth of field (DoF).
- Select the camera node and choose Add Arnold Properties from the Arnold toolbar.
- This will add the Arnold tab. Under there you will find the Depth of Field tab. Tick to enable DoF, and set the Focus Distance to 22. This value defines the area that will be sharp and in focus. With this value, the shoulders of the corkscrew will be in focus while the head and lower body will be defocused. Set the Aperture Size to 0.4. This is the amount of blur applied to out of focus areas.
- Render the scene to see the effect of adding DoF.
As you can see, after adding the DoF the noisy areas have been amplified.
- The first step in removing noise in an image with DoF is to check the alpha at the edges of the defocused object. As our corkscrew is against a background we will hide the studio by clicking on the blue visibility flag to the right of the node.
- Now render the image with Camera (AA) samples of 4, 8, 10, 14. Checking the alpha at the head or arm tip, will show the DoF smoothing out as the Camera (AA) samples increase.
- While 16 samples is arguably slightly smoother than 12, it's hard to justify the extra rendering time. So let's increase the Camera (AA) samples to 12 and unhide the studio geo.
When removing other types of noise it is good practice to render out with the AOVs to see exactly where the noise is coming from so that it can be fine tuned.
- To enable these AOVs, select the ROP and go to the Output tab. Click on the + to add four AOV's. Use the drop down arrow to the right of the AOV parameter to choose diffuse_direct, diffuse_indirect, specular_direct and specular_indirect.
The AOVs are viewable in MPlay from the drop down menu currently showing the beauty "C".
- Looking at the AOVs shows that the specular_indirect is still noisy on the body of the corkscrew. Increase Specular Samples to 6 to remove this.
You can download the result of this section below.
With these Sample settings, render times will have increased dramatically. Depending on your machine specs, you may want to experiment with some slightly lower values.
If your render times are still too long, the next part will cover rendering with a Z-Depth AOV and how to apply the DoF in Nuke.