I’m a french user of Blender and I found a simple way to add the MatCap look in Blender materials with the use of material node.
To see the matcap in the 3d viewport you need to active the glsl preview.
-First step: Get the matcap !
In ZBrush, open the modifiers options of the Material panel and move your mouse cursor over the little bottom picture:
(i.e. RedWax in default ZBrush material), do a screen capture to get this sphere picture.
-Next : Crop the circle.
Open a software to crop properly the sphere.
-Now you can open Blender.
In Blender, create a node material. You need to add only two node in your material node, the Texture node and the Mapping node.
The texture node is the picture precedently cropped.
The Mapping node is just for invert the Y axis (always the same).
Link the default mapping node (Vector in) to the normal channel of your material node (Normal out).
Link the texture node (Vector in) to the output of the mapping node (Vector out).
Link the color channel of the texture node (Color out) to the RGB output (COlor in).
Now, in the Mapping node, invert the Y channel : enter -1.0 in the second Size value.
That’s all !
Compare and enjoy.