I was able to duplicate the steps in the video in formZ for Maxwell.
Here's how it was done in the video:
1. Enable the "Shadow Matte" checkbox on each material in your project that you want the "ambient" style pass to affect
2. Enable the "Shadow" Channel in Maxwell Render Options > Image Tab.
- The Rubber material hint looks great for rubber objects, but it's going to be significantly less efficient to render than "Matte," which is very fast and may do just what you want. You can also try "Faster" if you need a slightly shinier material.
- If you are going for a "clay style" render, it's easiest to simply assign an MXM override to the entire scene. (Maxwell Render Options > Scene Tab)
- For a clay-style render, you can improve render time by de-selecting both options under "Reflected Caustics" and "Refracted Caustics" since they won't be needed (Maxwell Render Options > Image Tab)
- If you don't need depth-of-field, you can further improve render times by setting camera lens type to "pinhole." (Maxwell Render Options > Camera Tab)
- Generating extra channels takes some time, so if you find that you are satisfied with the clay style rendering and don't need the Shadow channel, make sure to disable it (Maxwell Render Options > Image Tab)