Hello Astan,
To colour the inside of the sphere differently from the outside without creating gaps or overlaps, you can use face normals to determine which side of the surface is visible and color them accordingly
Here's a sample code
% Create the isosurface
[fvf, fvv, fvc] = isosurface(KXi, KYi, KZi, Edis, EF);
% Calculate face normals
faceNormals = isonormals(KXi, KYi, KZi, Edis, fvv);
% Determine which faces are oriented outward and inward
% This is a simple heuristic: assuming the origin is inside,
% faces with normals pointing away from the origin are "outside"
faceCenters = (fvv(fvf(:,1), :) + fvv(fvf(:,2), :) + fvv(fvf(:,3), :)) / 3;
directionToOrigin = -faceCenters; % Vector pointing from face center to origin
dotProduct = dot(faceNormals, directionToOrigin, 2);
% Create logical indices for outside and inside faces based on dot product
outsideFaces = dotProduct > 0;
insideFaces = ~outsideFaces;
% Create the patch object
p1 = patch('Vertices', fvv, 'Faces', fvf(outsideFaces, :), ...
'FaceColor', 'green', 'EdgeColor', 'none');
hold on;
p2 = patch('Vertices', fvv, 'Faces', fvf(insideFaces, :), ...
'FaceColor', 'red', 'EdgeColor', 'none');
% Set up the view and lighting
daspect([1, 1, 1]);
view(3);
axis tight;
camlight;
lighting gouraud;
