While waiting hours and hours for a nested collection of 
semi-transparent isosurfaces to render, in order to show my Calculus 
students what was meant by a family of surfaces (hyperboloids in this 
case), it suddenly dawned on me that since I wasn't really concerned 
with reflections, refractions, interactions or shadows, that this was 
quite a bit of overkill, and that I could accomplish the same thing by 
using a container filled with "emission" media, defined by a density 
function representing my hyperboloids.  Besides being hundreds of times 
faster, I could also choose a container suited to the surfaces in 
question (in this example, a cylinder cut-off makes more natural-looking 
hyperboloids.)

This "discovery" may not seem surprising to most POV users, but I hadn't 
thought of it before, and it has led to some interesting new families of 
surfaces, and new ways (for me) of portraying old ones.

The second image shows a media-drawn "X-Ray" level surface, along side 
the isosurface, and below is its family of level surfaces.

Dave Matthews

Post a reply to this message

Attachments:
Download 'hyperboloids001.jpg' (40 KB) Download 'm&i_002.jpg' (34 KB)

Preview of image 'hyperboloids001.jpg'

Preview of image 'm&i_002.jpg'