  Astronomical data does not always use Cartesian coordinates. Both all-sky
observational data and simulations of rotationally symmetric systems, such as
accretion and protoplanetary discs, may use spherical polar or other coordinate
systems. Standard displays rely on Cartesian coordinates, but converting
non-Cartesian data into Cartesian format causes distortion of the data and loss
of detail. I here demonstrate a method using standard techniques from computer
graphics that avoids these problems with 3D data in arbitrary coordinate
systems. The method adds minimum computational cost to the display process and
is suitable for both realtime, interactive content and producing fixed rendered
images and videos. Proof-of-concept code is provided which works for data in
spherical polar coordinates.
