Find nodes in a mesh

Hello everyone, I hope someone can help me on this

I have a STL file imported, with it I created a triangulated mesh. Like the one in the image.

What I need is to find the nodes in the blue square ( -200<x<200& -200<y<200).I guess this information is in the big array of vertex from where I created this mesh. Then I need to know not only the nodes but the triangles that are in the area. I also have an array with "faces" information...

How can I get this?

Answer 1

[darova]

if matrix with faces/triangles like [1 2 3; 4 5 6; 7 8 9 ....

[~, indv] = find( -200<x & x<200 & -200<y & y<200 );    % indices of X and Y in square
indf = ceil(indv/3);                                    % indices of faces

see also inpolygon()