How To Create Cross Section In 3D

I have been simulating Mie scattering in 3D by using symmetry so that only 1/4 of my model has to be solved for. The problem I have is that I would like to plot the solutions of the full model with 1/4 of it cut out creating a cross section (See attached image for an example). I can easily get the rest of the model by performing two mirror operations, but I have not found out how to cut out the section or combine data sets in the right way. What is the best way to do this? Am I missing something simple?

Thank you,

Curtis Doiron