Matcaps is a 3ds Max tool for reproducing the viewport shading found in popular modeling applications such as ZBrush and Mudbox. It gives your models a matcap appearance in the 3ds Max viewport, matching the look those applications are known for.
The shading is applied as a temporary shader override in the viewport. Your original shaders and models stay untouched, which keeps the process non-destructive while you work.
Out of the box, Matcaps includes 35 matcaps. You can also add your own, or ones you download, by dropping them into the Matcaps textures folder. The tool supports 3ds Max 2017 or newer, and this release is version 1.0. A demo video is available for anyone who wants a closer look before installing.