You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: plot3d.m
    path of file: ./repos/Robotics-Toolbox/rvctools/release10.3.1/robot/@SerialLink
    
    the code of the file until where you have to start completion: %SerialLink.plot3d Graphical display and animation of solid model robot
%
% R.plot3d(Q, options) displays and animates a solid model of the robot.
% The robot is displayed at the joint angle Q (1xN), or
% if a matrix (MxN) it is animated as the robot moves along the M-point trajectory.
%
% Options::
%
% 'color',C         A cell array of color names, one per link.  These are
%                   mapped to RGB using colorname().  If not given, colors
%                   come from the axis ColorOrder property.
% 'alpha',A         Set alpha for all links, 0 is transparant, 1 is opaque
%                   (default 1)
% 'path',P          Overide path to folder containing STL model files
% 'workspa
    
function opt = plot_options(robot, optin)
    opt.color = [];
    opt.path = [];  % override path
    opt.alpha = 1;
    
        % timing/looping
    opt.delay = 0.1;
    opt.fps = [];
    opt.loop = false;
    
    opt.raise = false;
    
    % general appearance
    opt.scale = 1;
    opt.trail = [];
    
    opt.workspace = [];
    opt.floorlevel = [];

    opt.name = true;
    opt.projection = {'ortho', 'perspective'};
    opt.view = [];

    
    % tiled floor
    opt.tiles = true;
    opt.tile1color = [0.5 1 0.5];  % light green
    opt.tile2color = [1 1 1];  % white
    opt.tilesize = 0.2;
    
     
    % the base or pedestal
    opt.base = true;

    % wrist
    opt.wrist = true;
    opt.wristlabel = {'xyz', 'noa'};
    opt.arrow = true;
    
    % joint rotation axes
    opt.jaxes = false;
    
    
    % misc
    opt.movie = [];
    
    % build a list of options from all sources
    %   1. the M-file plotbotopt if it exists
    %   2. robot.plotopt
    %   3. command line arguments
    if exist('plotbotopt3d', 'file') == 2
        options = [plotbotopt3d robot.plotopt3d optin];
    else
        options = [robot.plotopt3d optin];
    end