pete4d
Do you have an idea how I could achieve being able to transform the origin of the polar projection similar to how I managed it working with Arnolds shipped nodes? Have a look at my video.
You could take advantage of the object space of the mesh. transform the meshe's vertices such that the projection center is at the origin, then transform the prim or a parent prim of the mesh back to the correct position (the inverse of the previous transform.) Then the space 'object' in the shader will refer to the un-transformed space.
To manually manipulate the space, the add and rotate nodes can be used. The transform matrix node was not implemented last time I tried to use it, but maybe that has changed. A matrix node requires a matrix though, so you're on your own for generating one using python or vex or something and then pasting the values in. materialX is missing the required nodes for actually manipulating or importing matrices.