Linear Workflow and Gamma Correction Part 2

If you have read the first part of my gamma correction article, you should now understand exactly why this alteration to your workflow is necessary.

In this second part, I will look at the built-in linear workflow within Autodesk 3ds Max. It is the quickest method as it is controlled entirely by 3ds Max and requires no disruption to your existing workflow.

The test scene

We will be using the test scene in figure 1 for all of the examples. It is a very basic scene consisting of a box with a wooden floor, a camera, 3 VRay lights and a simple structure acting as the light fitting. All render, material and light settings will remain the same, unless otherwise stated.

Figure 1. The test scene

The 3ds Max preference method

When the above scene is rendered with default 3ds Max settings, the result is figure 2.

Figure 2. Default settings

As you can see, the image is very dark with almost no detail in the darker areas. Previously, most users would just try and compensate for the lack of light by either increasing the intensity or even quantity of the lights. As explained in part 1, there are obvious drawbacks to this. Figure 2 illustrates the effect of increasing the intensity of the lights.

Figure 3. Higher intensity lights

Although you may have accomplished your goal of getting more light into the scene, you have also introduced some very small artifacting around the lid of the teapot as well as a severe hotspot on the back wall. If you cannot see this highly contrasted hotspot, try raising your chair ever so slightly. You will see that the gradient is very sharp and not at all realistic.

What you should be doing is gamma correcting both the input and output. The simplest method is to go to Customise > Preferences > Gamma and LUT, and select the settings shown in figure 4.

Figure 4. Gamma and LUT preferences

Once these preferences have been set, our rendered test scene looks like figure 5.

Figure 5. 3ds Max gamma correction

The benefits are there for you too see but, if you need any reminding, please refer back to the previous section which lists, in detail, the full benefits of working in a linear workspace.

Because we aren't doing any post-processing with this scene, it is perfectly acceptable to export a non-linear gamma corrected image. If you were intending on post-processing the image, you would need to override the output in the 'Save as' dialogue box or alternatively disable the 2.2 output default in the preferences. You will also need to output in anything other than the JPEG format! We recommend either half float OpenExr, 16-bit TIFF or PNG, anything else is either overkill or doesn't contain enough image data.

I'm sure you will agree that this method is very simple and we hope you can see the benefits of making this change to your workflow. In the upcoming articles, we will cover the manual methods of both VRay and Mental Ray with 3ds Max.

To find out more, get in touch with the team on 03332 409 309 or email 3D@Jigsaw24.com.