I use a lot of 3D graphs. With an orthogonal rendering mode, every node gets the same size, which makes navigation quite difficult.
Everything seems to be in place to support a perspective rendering mode.
Please find attached a patch to add an entry to the NodeLinkDiagram right-click menu.
Moreover, I propose to enable perspective view by default, since it makes navigation in the graph easier. See the constructor of GlScene (tulip-ogl/src/GlScene.cpp +88).