How to plot 3D grid (cube) in Matlab

Question

Hi I would like to plot transparent cube-shaped grid with lines in it. Something like this:

Answer 1

I understand this is a late reply but it is still valid in case anyone else is looking at doing the same thing.

Assuming you are plotting cubes (/their edges), an alternative to the answers already provided is to use the 'plotcube' code from Oliver: plotcube

The advantage of this solution is that you can:

1. Change the transparency of the faces (FaceAlpha), and/or,
2. Change the transparency of the edges (EdgeAlpha), and/or,
3. Change the colour of the lines (EdgeColor).

All of these can be constants, or variables. (e.g. fixed edge colour, or a colour that changes with Z-value etc.)

To add in functionality of 2. and 3. (above) change the 'cellfun(@patch...' section in Olivers code, adding in the four extra lines of code as follows: (replace the whole cellfun section with this; including the new 'EdgeAlpha' and 'EdgeColor' lines):

cellfun(@patch,XYZ{1},XYZ{2},XYZ{3},...
  repmat({clr},6,1),...
  repmat({'FaceAlpha'},6,1),...
  repmat({alpha},6,1),...
  repmat({'EdgeAlpha'},6,1),...
  repmat({0.2},6,1),...      % Set this value to whatever you want; even a variable / matrix
  repmat({'EdgeColor'},6,1),...  
  repmat({'black'},6,1)...
  );

For more info on 'patch' please see patch documentation.

An important note: - for large models (many cubes) this is very slow to run. e.g. running this 'plotcube' function in a 'for' loop in MATLAB over thousands of blocks. I believe this is from calling the 'patch' function multiple times. A better solution would be to vectorise; to put all your points (vertices/faces/whatever) together in a single matrix first and then call the @patch function only once (no 'for' loop). This would require changing the code somehow to update all the XYZ data.

I hope that helps someone.

Here is the 'plotcube' code in case the link to the original code by Oliver breaks someday:

function plotcube(varargin)
% PLOTCUBE - Display a 3D-cube in the current axes
%
%   PLOTCUBE(EDGES,ORIGIN,ALPHA,COLOR) displays a 3D-cube in the current axes
%   with the following properties:
%   * EDGES : 3-elements vector that defines the length of cube edges
%   * ORIGIN: 3-elements vector that defines the start point of the cube
%   * ALPHA : scalar that defines the transparency of the cube faces (from 0
%             to 1)
%   * COLOR : 3-elements vector that defines the faces color of the cube
%
% Example:
%   >> plotcube([5 5 5],[ 2  2  2],.8,[1 0 0]);
%   >> plotcube([5 5 5],[10 10 10],.8,[0 1 0]);
%   >> plotcube([5 5 5],[20 20 20],.8,[0 0 1]);

% Default input arguments
inArgs = { ...
  [10 56 100] , ... % Default edge sizes (x,y and z)
  [10 10  10] , ... % Default coordinates of the origin point of the cube
  .7          , ... % Default alpha value for the cube's faces
  [1 0 0]       ... % Default Color for the cube
  };

% Replace default input arguments by input values
inArgs(1:nargin) = varargin;

% Create all variables
[edges,origin,alpha,clr] = deal(inArgs{:});

XYZ = { ...
  [0 0 0 0]  [0 0 1 1]  [0 1 1 0] ; ...
  [1 1 1 1]  [0 0 1 1]  [0 1 1 0] ; ...
  [0 1 1 0]  [0 0 0 0]  [0 0 1 1] ; ...
  [0 1 1 0]  [1 1 1 1]  [0 0 1 1] ; ...
  [0 1 1 0]  [0 0 1 1]  [0 0 0 0] ; ...
  [0 1 1 0]  [0 0 1 1]  [1 1 1 1]   ...
  };

XYZ = mat2cell(...
  cellfun( @(x,y,z) x*y+z , ...
    XYZ , ...
    repmat(mat2cell(edges,1,[1 1 1]),6,1) , ...
    repmat(mat2cell(origin,1,[1 1 1]),6,1) , ...
    'UniformOutput',false), ...
  6,[1 1 1]);


cellfun(@patch,XYZ{1},XYZ{2},XYZ{3},...
  repmat({clr},6,1),...
  repmat({'FaceAlpha'},6,1),...
  repmat({alpha},6,1)...
  );

view(3);