"Bald Eagle" <cre### [at] netscapenet> wrote:
> "- I have tried to show how one can construct the control grid so that the
> patches are joined smoothly. All the 8 control points surrounding each corner of
> the patches are placed in the same plane."
>
> Thanks - this may help me re-think things.
>
> Can you elaborate a little bit on the implied relationship between the small
> vectors between the corner and control points, and the larger vector between
> corners is?  And why?
>
> I understand the necessity of having the same slope which I believe is what the
> small patch shows, and can understand that in isolation, but I haven't yet made
> the connection to understand the relation between that and the large vectors.

I assume that you are looking at my 'Bezier_Patches_Stitched' files.

IIRC I added the large vectors as a suggestion for how one can create the
smaller vectors between the points in the control grid around the white corner
points. (The positions for these white corner points were specified "manually".)

The white corner points, together with their corresponding two small vectors,
defines the planes for the 8 control points surrounding each corner point. The
small vectors are also used to control the distances between these control
points.

AFAIK it is common to let the small vectors have the same direction as the large
vectors and to let their lengths be 1/6 of the length of the large vectors.

But I think that one can choose other orientations and lengths for the small
vectors (but I have not had time to experiment with this yet).

In the attached image I have given each Bezier patch a random color and placed
the camera at a different position.

--
Tor Olav
http://subcube.com

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