It is my understanding that you would like to insert a plane into the 3D truss you have.
Use the patch function and insert the plane in the truss frame. It can be done in the following way:
% For the sake of explanation, I have created a truss with rigid plates and inserted the plane therein
% Define the coordinates of the truss nodes
nodes = [0, 0, 0; 0, 0, 5; 0, 5, 0; 0, 5, 5; 5, 0, 0; 5, 0, 5; 5, 5, 0; 5, 5, 5];
% Define the connectivity matrix for the truss elements
connectivity = [1, 2; 1, 4; 1, 5; 2, 3; 2, 6; 3, 4; 3, 7; 4, 8; 5, 6; 5, 8; 6, 7; 7, 8];
% Define the coordinates of the rigid plates
plateVertices = [0, 0, 0; 0, 5, 0; 5, 5, 0; 5, 0, 0];
% Define the coordinates of the plane vertices
planeVertices = [0, 0, 1; 0, 2.5, 1; 5, 2.5, 1; 5, 0, 1]; % Can also replace with the indices of the desired truss nodes for the plane
% Plot the truss
figure;
hold on;
% Plot the truss nodes
scatter3(nodes(:, 1), nodes(:, 2), nodes(:, 3), 'filled');
% Plot the truss elements
for i = 1:size(connectivity, 1)
startNode = nodes(connectivity(i, 1), :);
endNode = nodes(connectivity(i, 2), :);
line([startNode(1), endNode(1)], [startNode(2), endNode(2)], [startNode(3), endNode(3)]);
end
% Plot the rigid plates
patch('Vertices', plateVertices, 'Faces', [1, 2, 3, 4], 'FaceAlpha', 0.5, 'FaceColor', 'blue');
% Plot the plane
patch('Vertices', planeVertices, 'Faces', [1, 2, 3, 4], 'FaceAlpha', 0.5, 'FaceColor', 'red');
% Set axis labels and limits
xlabel('X');
ylabel('Y');
zlabel('Z');
axis equal;
grid on;
% Adjust the view angle
view(3);
