How can I cut(crop) patch(3d,stl file) object?

Hi I want to know how can I crop 3D patch in matlab

I have a Data 'skull' it is from .STL file ( It is from stl file and I read stl file from my matlab)

    skull = stlread('Skull.stl')
    patch(skull,'FaceColor', [0.8 0.8 1], 'EdgeColor','none', 'FaceLighting',    'gouraud', 'AmbientStrength', 0.15);
    camlight('headlight');
    material('dull');

(( skull data is struct like this))

And then I make a patch about skull (like this)

But that skull data quite large So I want to crop some region which is I interested (Like this)

((this picture just specify the plot range. like below ))

    axis ([0,100,0,100,0,100])

But I want to save plot(patch) which is cropped as a Data like 'skull'

So I try it like below (I interest in range that is bigger than(0,0,0))

    x = 0;
    y = 0;
    z = 0;
    [r] = find((skull.vertices(:,1)>=x) & (skull.vertices(:,2)>=y) & (skull.vertices(:,3)>=z));

    for i = 1:size(r,1)
    interest.vertices(i,:) = skull.vertices(r(i,1),:);
    % interest.faces(i,:) = skull.faces(r(i,1),:);
    end

    for i = 1:size(r,1)/3
        interest.faces(i,3) = 3*i;
        interest.faces(i,2) = 3*i-1;
        interest.faces(i,1) =3*i-2;
    end

And then I patched Data interest

    patch(interest,'FaceColor', [1 0 0], 'EdgeColor','none', 'FaceLighting',    'gouraud', 'AmbientStrength', 0.15);
    camlight('headlight');
    material('dull');

So I got a patch(plot) like this

The overall shape exists but there is a lot of hole in the middle. How can I solve this problem? and What did I do wrong?

[tejas alva]

Hey! Did you figure out how to do this?

[Tom Cristiani]

I was trying to do the same thing and came up with this function. I hope it helps!

The edges wind up a bit frayed. I might clean that up in a revision.

function [fv] = cropPatch(fvIn,xRange,yRange,zRange)
    
    % fvIn is a typical patch structure containing "vertices" and "faces" fields
    % xRange, yRange, and zRange are two element vectors in the form [xMin xMax], [yMin yMax], [zMin zMax] 
    % fv is the new cropped patch structure
    
    vertexIndex = (fvIn.vertices(:,1) > xRange(1)) & (fvIn.vertices(:,1) < xRange(2)) & ...
        (fvIn.vertices(:,2) > yRange(1)) & (fvIn.vertices(:,2) < yRange(2)) & ...
        (fvIn.vertices(:,3) > zRange(1)) & (fvIn.vertices(:,3) < zRange(2));
    
    vertexNums = find(vertexIndex);
    
    fv = struct('vertices',[],'faces',[]);
    
    faceIndex = ismember(fvIn.faces(:,1),vertexNums) & ...
        ismember(fvIn.faces(:,2),vertexNums) & ...
        ismember(fvIn.faces(:,3),vertexNums);
    
    fv.vertices = fvIn.vertices(vertexIndex,:);
    fv.faces = fvIn.faces(faceIndex,:);
    
    [~,replaceIndex] = ismember(fv.faces,vertexNums);
    
    fv.faces = replaceIndex;
    
end

[Rawan]

Where is the model please?

[naomy_yf]

i'm using the face and ver files to reindex the face and ver I need then creat the patch again.

Answer 1

[Mitchell Carlson]

I had a similar problem and found that using the xlim, ylim, and zlim functions worked. In this case you could do something like this:

xlim = ([0 100]) % This only displays values with x between 0 and 100

ylim = ([0 100]) % Same thing for y

zlim = ([0 100])