The name travels with the drawing into whatever the output can hold: a DXF file records it, a TikZ picture writes it into a comment. It never affects the geometry.

 D = draw.Drawing ('bracket');
 D = D.polyline (geom.Polyline ([0, 0; 60, 0; 60, 40; 0, 40], ...
                                'Closed', true));
 D.Name

ans = bracket

Renaming an existing drawing is an ordinary assignment, because the name is a property and not something fixed at construction.

 D.Name = 'bracket rev B';
 D.Name

ans = bracket rev B

The current layer is where entities go as they are appended. A layer carries a colour, a line type and a line weight, and an entity takes them from its layer unless told otherwise, so with the layers defined, changing the current layer is the one step that changes the pen.

 D = draw.Drawing ('shaft');
 D = D.layer ('BODY', 'LineWeight', 0.5);
 D = D.layer ('HIDDEN', 'Linetype', 'HIDDEN', 'LineWeight', 0.25);
 D = D.layer ('AXES', 'Linetype', 'CENTER', 'Colour', 'red', ...
              'LineWeight', 0.25);
 D.Layer = 'BODY';
 D = D.polyline (geom.Polyline ([0, -15; 70, -15; 70, 15; 0, 15], ...
                                'Closed', true));
 D.Layer = 'HIDDEN';
 D = D.line ([25, -15], [25, 15]).line ([50, -15], [50, 15]);
 D.Layer = 'AXES';
 D = D.line ([-6, 0], [76, 0]);
 D.layers ()

ans =
{
  [1,1] = 0
  [1,2] = AXES
  [1,3] = BODY
  [1,4] = HIDDEN
}

 plot (D);
 title ('three layers, each with its own line type and weight');

layer also changes a layer already there, and everything drawn on it follows: the axes turn blue without touching a single entity. A layer that is not plotted is drawn on screen and left off paper.

 D = D.layer ('AXES', 'Colour', 'blue');
 D = D.layer ('NOTES', 'Plot', false);
 D.Layer = 'NOTES';
 D = D.text ([0, 22], 'check the bore spacing', 3.5);

 figure ();
 plot (D);
 title ('the axes restyled, and a note that will not print');

The current line type governs what is appended after it is set. Here one drawing carries five, and each run of geometry keeps the type it was drawn with.

LTScale multiplies the dash lengths, which are model dimensions: on a short line the pattern needs enlarging before it reads as itself.

 D = draw.Drawing ('types');
 y = 0;
 for lt = {'CONTINUOUS', 'HIDDEN', 'CENTER', 'PHANTOM', 'DASHDOT'}
   D.Linetype = lt{1};
   D = D.line ([0, y], [60, y]);
   D = D.text ([63, y - 1.2], lt{1}, 3.5);
   y -= 7;
 endfor
 plot (D, 'LTScale', 2);
 title ('one drawing, five line types');

A colour is an AutoCAD index, or a name that draw.colour resolves to one. It applies to what is appended after it is set.

 D = draw.Drawing ('colours');
 x = 0;
 for c = {'red', 'yellow', 'green', 'cyan', 'blue', 'magenta'}
   D.Colour = c{1};
   D = D.circle ([x, 0], 9);
   x += 22;
 endfor

256 is 'byLayer', the default: the entity takes whatever colour its layer carries, which is how a CAD drawing is normally organised.

 D.Colour = 256;
 D = D.line ([-12, -14], [x - 10, -14]);
 plot (D);
 title ('six named colours, then byLayer');