Cube with different side color in RGB

I created a cube using rigid body tree (code below). Then I wanted to color different sides of the cube, red, gree, blue, etc... but when I use the command

addVisual(body, 'box', [1 1 1], 'FaceColor', 'r');

for a side to be in red color, the issue is, it is giving me error of too many arguments.

cube = rigidBodyTree;
body1 = rigidBody('body1');
joint1 = rigidBodyJoint('joint1','floating');
body1.Joint = joint1;
addVisual(body1, 'box', [1 1 1], 'FaceColor', 'r'); 

Error using robotics.manip.internal/RigidBody/validateAddVisualInputs
Too many input arguments.

Error in robotics.manip.internal.RigidBody/addVisual (line 215)
validType = validateAddVisualInputs(obj, type, parameter, varargin{:});

Error in rigidBody/addVisual (line 231)
obj.BodyInternal.addVisual(Inputs{:});

addVisual(body1, 'box', [1 1 1]);
%addVisual(body1, 'box', [1 1 1], 'FaceColor', colors{i});
addBody(cube,body1,cube.BaseName);

[DGM]

I don't have that toolbox, but I think you might just have to set those properties after calling addVisual(). That's what other examples seem to do.

https://www.mathworks.com/matlabcentral/answers/2063452-how-to-change-the-color-of-a-rigidbody-visual

[jari jafri]

Thanks

Answer 1

[Karsh Tharyani]

Hi @jari jafri,

The addVisual function on a rigidBody doesn't support the additional name-value arguments that you are trying to pass i.e., "FaceColor". I have conveyed this enhancement request to the development team at MathWorks for a future release of MATLAB.

As a workaround, you can try to use findobj and set to modify the patch colors.

Here are some code snippets to illustrate:

rbt=loadrobot('kinovagen3');
ax=show(rbt);

% All the visual mesh patches on the rigid body tree visualization
patches=findobj(ax.Children,'-regexp','DisplayName','_mesh');

patches = 
  8x1 Patch array:

  Patch    (DO_NOT_EDIT_CTQxT)
  Patch    (DO_NOT_EDIT_CTQxT)
  Patch    (DO_NOT_EDIT_CTQxT)
  Patch    (DO_NOT_EDIT_CTQxT)
  Patch    (DO_NOT_EDIT_CTQxT)
  Patch    (DO_NOT_EDIT_CTQxT)
  Patch    (DO_NOT_EDIT_CTQxT)
  Patch    (DO_NOT_EDIT_CTQxT)

% Set the ForeArm_Link's visual mesh color to "magenta". 
forearmlinkmeshes=findobj(patches,'-regexp','DisplayName','ForeArm_Link_mesh');
set(forearmlinkmeshes,'FaceColor','magenta');

% Set all the visual mesh patches of the robot to the color 'blue'
set(patches,'FaceColor','blue');

Hope this helps,

Karsh