what would be a use change in the viewer's position that isn't homomorphic with changing the object's orientation?

The data that I'm setting this up to graph -- my reason for doing this -- is large: maybe 1000 or more values wide (X); upto 100 or so deep in the Z dimension; and 16 (or even 32) lines (same Xs different Ys) plotted in each Z-plane.

Far too much data to take in as a single picture, but this is about exploring the data, not presenting it.

The desire is to be able to 'walk-in' to the graph and rotate it about me. To be able to walk down the lines looking for where crossovers occur; and then measure those crossover points reasonably accurately. And (ideally) to be able to click on 'unimportant' lines and have them disappear so as to clarify the view. Perhaps change the color of lines interactively or select and highlight particular sections of lines.

That's why I'm going for vector graphics. I've tried this exercise before several times, most recently a few years ago using Tk and Win32::Gui, but the former is just too slow and memory hungry; the latter too badly documented.

Many years ago I developed something that ran on a peculiar beast called an IBM 3270 PC which was effectively just an intelligent graphical terminal to several million £s worth of mainframe at IBMs uk research lab. It was going quite well, but the project was canceled and I moved on to a completely different project.

But I think that with SVG and the performance of JS in modern browsers, along with a half descent graphics processor, it ought to now be feasible.