Create a surface between two sets of 3d data points

Hi,

I have 2 sets of data points that create lines on a 3-Dimensional plot.

I would like create a linear surface between the two sets of data points. Each data point on one set of data would correspond with the data point on the other set. I am unsure of how to go about this other than finding a linear equation for each coupled data points.

r1 = [-2.2607e-05; 1.1301e-08; 1.4319e-04; -1.4319e-04];
x = linspace(0,1000);
y = x;
u1_3 = (r1(1)*x.^2 + r1(2)*y.^3); 

figure(3)
hold on
grid on
scatter3(x,y,u1_3-100,'b')
X2 = linspace(0,0);
Y2 = linspace(0,1000);
Z2 = linspace(0,0);
scatter3(X2,Y2,Z2-100,'k')
zlim([-1e3 0])
ylim([-1000 1000])
xlim([-1000 1000])
xlabel('x (meters)')
ylabel('y (meters)')
zlabel('Deflection, m/V')
hold off

Any help on this is much appreciated!

[Clayton Gotberg]

I'm al bit confused about your goal here. Do you want to take two sets of coordinates and create a surface that is always in the middle of both of them? See the below chart (but imagine it in 3 dimensions instead).

[Matthew Davenport]

@Clayton Gotberg, yes the first data point of the first set (x,y,u1_3) should have a linear line to the first data point of the second set (X2,Y2,Z2). When the first and second set of data points are plotted they form two independent lines, I want to create a linear surface whose end points are the two lines

[Matthew Davenport]

[Sean de Wolski]

What are you trying to do with this surface? Just visualizing, using it to interpolate?

[Matthew Davenport]

I would like to show the normal vectors of the surface. The blue set of data represents an actuartor arm position with a surface conected to the black data set.

Answer 1

[Clayton Gotberg]

When you send matrices to the plotting command, the way that it plots depends on the orientation of those matrices

% x, y, z already defined as row matrices (1 x n)
X = [x1; x2]; % Create a matrix with x1(1) above x2(1); do the same for Y and Z
Y = [y1; y2];
Z = [z1; z2];

plot3(X,Y,Z) % Result: n lines with two points (x1,y1,z1) and (x2,y2,z2)

plot3(X',Y',Z') % Result: 2 lines with n points 

If you are trying to create a surface, specifically, the surf command should take the exact same inputs and create a single surface.

[Matthew Davenport]

Thank you for your help! I would also like to show the surface normals, however surfnorm returns an error that z must be at lease 3-by-3. Do you have any suggestions?

[Clayton Gotberg]

I would guess that the error is because surfnorm needs more information to calculate the normal vector than is present in a 2 x n array. If you want to include the normals, you will probably need to calculate and plot them yourself instead of using that function. I'm also not certain what normal you're looking for as a line has infinite normals. You'd need to define a plane and then either find the normal vector to that plane or find a line perpendicular to the line of interest in that plane.