Octane for Houdini

The Matcap projection type will correctly apply Matcap textures onto surfaces. Connect a RGB Image node containing the matcap texture into the desired material channel, and wire the Matcap node into the projection type (figure 1).

Figure 1: A Matcap projection node used to correctly project a matcap texture connected to the Diffuse pin on a Diffuse material node. 

Figure 2: The node network associated with the results in figure 1