Make a contour plot of a 3D Solid Object

Hi, I want to make a contour plot of my 3D Mesh. The 3D mesh is not a surface. But a solid object. I have already extract the faces of the object. But still cannot make a contour. Anyone know how to do that? Also, if I can make the contour, can I extract the laterl position of these equal height lines? I want to do some calculation on these equal height lines, such as calculating the lateral distance between two equal height lines. Below are the pictures of my 3D mesh. The first one is just a solid scatter of my object. The second is the pdeplot. The third is the nodes on the face 1, and face 7.

NOTE: I only want the equal hight line of the part that can be hitted by a sunlight came from the top along the z axis.

[darova]

Looks like you have a sphere. Contours of a sphere are just circles. You want circles?

[Tianshu Yu]

Well, yes currently I want circles. However, the difficult part is first this shape is triangulated rather than a rectanuglar mesh. Second, I don't want equal hight line of the downside half of the circle. I only want the upper side. It just like that when you hit a sunlight on the shape anything in the shadow would not have a hight. I only want the equal hight line of the part that can be hitted by a sunlight came from the top along the z axis. Also, sphere is not my final goal. I would like the algorithm to works on any shape. Not just these shapes which are convex.

Answer 1

[Mingta Yang]

Check out fill3. It might be what you need.

Answer 2

[KSSV]

You can plot contours of triangulated data using this:

https://in.mathworks.com/matlabcentral/fileexchange/38858-contour-plot-for-scattered-data?focused=5249779&tab=function

[Tianshu Yu]

Well, the function is great, but I cannot generate a TRI matrix. Because the shape above is generated by the function generateMesh(). And the setting is 'quadratic'. So each tetrahedra is composed of 10 nodes rather than 4 nodes. Is there a way to get around this?