I have now looked into the problem of modelling shapes of
arbitrary topology by using POV-Ray's built-in bicubic patches.

For such shapes, it is often necessary to have more (or less)
than four such patches meet at a single point. How to do this
seems to be a non-trivial problem. (At least for me.)

But now I have rewritten my macros (again) to allow for such
topologies. To model a shape, one must put all the coordinates
for the control points in a 1-dimensional list. Then one must
put all the patches in another 1-dimensional list. Each patch
therein is defined by the numbers of the 4 control points, that
controls each patch. (These 4 numbers must be written in anti-
clockwise order.)

When the information above is given, the macros will calculate
the information that is needed to make the transitions between
the patches smooth. (Other macros will place all the patches.)

The patchwork shown in these images has a point were five bicubic
patches meet. (The macros will allow any number of patches to
meet at any point.)

You'll probably notice that the shape is not "perfect". But it
can be refined by setting the patch resolution higher; i.e. by
defining more control points (and thereby more patches) for the
same region of the shape.

The 2nd image is an orthographic top view and the 4th image shows
where the control points are located.


Any comments ?


Tor Olav

Post a reply to this message

Attachments:
Download 'FivePatches13.jpg' (28 KB) Download 'FivePatches14.jpg' (30 KB) Download 'FivePatches15.jpg' (26 KB) Download 'FivePatches16.jpg' (29 KB)

Preview of image 'FivePatches13.jpg'

Preview of image 'FivePatches14.jpg'

Preview of image 'FivePatches15.jpg'

Preview of image 'FivePatches16.jpg'