Cutting area plot matlab

I have a given 3D surface plot My problem is drawing an area, f and cutting out exactly this area from the given plot.Please help!

[darova]

Show your data. Show your code. Open yourself up for us!

[Jerry]

i have a random 3d surface plot like in the picture, and programmed a triangle into the plot.

how do I substract exactly this shape of the triangle(in pink) from my given plot, so that there is a triangle area of the plot cut out?

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[darova]

What about this?

clc,clear

% generate surface
r = 0:0.1:5;
t = linspace(0,2*pi,30);
[T,R] = meshgrid(t,r);
Z = 5*sin(R)./R;
[X,Y] = pol2cart(T,R);

% data for cutting
x = [1 3 0.7];
y = [0.2 0.3 3];
z = [1 1.2 1];

ix = convhull(X(:),Y(:));           % boundary of surface
x1 = X(ix(1:end-2));                % vertices of boundary
y1 = Y(ix(1:end-2));
gd1 = [2; length(x1); x1(:); y1(:)];               % surface boundary geometry
gd2 = gd1;  
gd2(1:2+2*length(x)) = [2; length(x); x(:); y(:)]; % cutting plane boundary geometry
dl = decsg([gd1 gd2],'P1-P2',char('P1','P2')');    % decomposite geometry
[p,e,t] = initmesh(dl,'hmax',0.5);                 % create mesh

F = scatteredInterpolant(X(:),Y(:),Z(:));
zz = F(p(1,:),p(2,:));  % calculate Z coordinate for each mesh point
fv.vertices = [p;zz]';  % x y z data
fv.faces = t(1:3,:)';   % connection list of faces

cla
patch(fv,'facecolor','r')   % surface
patch(x,y,z,'g')            % cutting plane
view(150,45)
axis vis3d 

If you have boundary intstead of convhull

ix = convhull(X(:),Y(:));           % boundary of surface

[Jerry]

thank you, but i have had a random surface sent to me and I dont even have the function for the surface. up there I just postet an example. so what do i do if i don't have information according to the given surface, just the geometrical position of all the points in the mesh?

[darova]

You don't need mesh. Try only points

[Jerry]

it doesn't work, maybe it has something to do with the fact that my given plot is an SGplot with a large Vertex and Facet list

[darova]

Can you attach the data?

[Jerry]

please help

[darova]

Can you attach the data for the picture?

[Jerry]

here's the picutre

[darova]

I choosed XZ plane to detect if points inside triangle (i used inpolygon)

Since there are another vertices inside i added Y axis condition:

where y1 - triangle verices, y2 - surface vertices

Result

Was not that easy! See attached script

[Jerry]

thank you so much! it is perfec!!!