如何從Matlab中的標量數據生成這個特定的3D圖形？

Question

我想用Matlab來產生這個圖。內置的橢球功能令人困惑。對於這個問題，我有兩個變量（寬度和長度）和一個恆定的高度。

爲了讓它變得非常簡單我想說明，當我們接近尖端時，寬度是變化的，但高度是恆定的。 w，x，h是圖中顯示的變量。

我真的很感激，如果有人可以幫忙。

Answer 1

下面的代碼可以讓你很長的路要走，我想。見例如輸出：

我添加足夠多的意見，你應該能夠把它從這裏...

% plot ellipsoid in 3D 

% height and width of ellipsoid: 
e_h = 10; 
e_w = 3; 

% position where the "quivers" (arrows) go: 
q_offset = 2; % distance from axis 
q_scale = 0.5; % multiplier to give parabola some size 
q_spacing = 0.5; % distance between arrows 
q_height = 2.5; % height above XY plane where arrows are drawn 
N = 1000;  % number of points for drawing 

theta = linspace(0, 2*pi, N); % parameter to help drawing ellipse 
zerov = zeros(1, N);   % array of zeros that I will need 

% coordinates of main ellipse: 
x = e_w * sin(theta); 
y = zeros(size(x)); 
z = e_h * cos(theta); 

% plot main ellipse: 
figure; 
plot3(x, y, z) 

% secondary plot 
y2 = q_scale*(e_w.^2 - x.^2) + 2; % offset parabola - what your plot looked like... 
hold on 
plot3(x, y2, zerov+q_height);  % plotting the parabola in the XY plane at height 
axis equal % make the plot dimensions isotropic 

% add quivers 
q_base = -e_w:q_spacing:e_w; % x coordinate; y and z are fixed 
q_length = (e_w.^2 - q_base.^2)*q_scale; % length of quiver - just an equation I chose 
q0 = zeros(size(q_base)); % another vector I will need multiple times 
q1 = ones(size(q_base)); % ditto 

% plot the arrows: the "-1" argument means "don't scale" 
quiver3(q_base, q0+q_offset, q_height*q1, q0, q_length, q0, -1)