# Why won't the InterpolationOrder function properly?

data1 = {{0, 0, 1738.946},
{0, 24, 1700.418},
{0, 48, 1698.078},
{32.05, 0, 1772.551},
{32.05, 24, 1736.689},
{32.05, 48, 1722.127},
{64.10, 0, 1999.362},
{64.10, 24, 1969.550},
{64.10, 48, 1919.607}};

plot1a = ListPointPlot3D[data1, BoxRatios -> 1, PlotStyle -> Directive[Black, PointSize[.05]]];

plot1b = ListPlot3D[data1, InterpolationOrder -> 2, BoxRatios -> 1, Mesh -> None];

Show[plot1a, plot1b]


• Why don't you tell us a bit more. For instance, what is wrong with the result you obtain? What would you like to obtain instead? Commented May 11, 2016 at 22:58

I'm not sure why InterpolationOrder -> 2 isn't working for you, but here is a work-around you might use.

data = {{0, 0, 1738.946}, {0, 24, 1700.418}, {0, 48,
1698.078}, {32.05, 0, 1772.551}, {32.05, 24, 1736.689}, {32.05,
48, 1722.127}, {64.10, 0, 1999.362}, {64.10, 24,
1969.550}, {64.10, 48, 1919.607}};

plot1a =
ListPointPlot3D[data,
BoxRatios -> 1, PlotStyle -> Directive[Black, PointSize[.05]]];

iF = Interpolation[data, InterpolationOrder -> 2];

plot1b =
Plot3D[iF[x, y], {x, 0, 65}, {y, 0, 48}, BoxRatios -> 1, Mesh -> None];

Show[plot1a, plot1b]


However, I think the plot would look better with small spheres in place of the 2D points you used to show the mesh. So I would use

plot1c =
With[{span = 2000 - 1700},
Graphics3D[
{GrayLevel[0.6], Ellipsoid[#, 10 {64/span, 48/span, 1}] & /@ data},
BoxRatios -> 1]]

Show[plot1c, plot1b]