how do I calculate and highlight values in a 3d graph?

what command do I use to highlight a point on a graph and calculate its corresponding values. Ex: I want to know the value of y and z @ x=3.5 on my 3D graph and highlight the point.

Answer 1

[KALYAN ACHARJYA]

plot3(x,y,z);
hold on;
grid on;

Get the indice where x=3.5

id=find(x==3.5)

Get the corresponding y and z value

y_data=y(id);
z_data=z(id);

Let suppose you wish to highlight the point where, x=3.5 and corresponding y and z

plot3(x(id),y(id),z(id),'r*','linewidth',2);

Note on Two Things here:

1. Ensure that there must be respective x value within the x data (which you are looking for), so that id to be non empty data.
2. Comparing floating points data, very careful, see the following threads

https://in.mathworks.com/matlabcentral/answers/39723-relational-operators-issue-1-is-not-equal-to-1-000

http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F