currently, an advantage height fields have is a defined inside and
outside.  would your method also have this?  plus, i can make cuts from
height fields (like caves).  would yours be able to do this as well? 
other than that.  it sounds nice.  i'm off to check your pics!

John VanSickle wrote:
> 
> I submit this for the consideration of interested parties.
> 
> While reading up on a version of a subdivision surface scheme, I
> developed the idea of using a simplified version of it to provide
> smooth interpolation of height field data.
> 
> The method builds a small quartic patch around each of the interior
> points of the height field.  The coefficients for this quartic are
> based on the value of that point and each of its eight neighbors.
> When clipped properly the patches all meet perfectly, and there are
> no discontinuities in the surface normal across the borders.
> 
> The result is a smooth surface across the entire height field with
> no creases or seams.
> 
> The advantages are:
> * There is no "stepping" as is commonly observed in height fields,
>   especially 8-bit height fields.  A gently rising set of data
>   points yields a gently sloping surface.
> 
> * There is no need for smoothing calculations; the patches are
>   naturally smooth.
> 
> The disadvantages are:
> 
> * Slightly more data is needed to generate the same number of squares.
>   In a normal height field, an M x N image will produce a (M-1) x (N-1)
>   set of squares, which are comprised to two triangles.  This new
>   method produces a (M-2) x (N-2) set of patches.
> 
> * The patches are mostly quartic objects; however some of them will be
>   cubic, quadratic, or even linear.  Furthermore, a bounding box is
>   very easy to calculate for each patch.  The method will be slower in
>   any event.
> 
> I have posted some code that demonstrates this method, and an MPG
> animation of it, in p.t.s-f and p.b.a.
> 
> So, what do you think?
> 
> Regards,
> John
> --
> ICQ: 46085459

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