For the protective face shield on the helmet, you'll create one large multi-sided polygon using the Append to Polygon Tool and then split it into multiple four-sided polygons (quads) so that the new polygons match the existing four-sided topology of the helmet mesh.

To create the face shield using the Append to Polygon Tool

1. Tumble the perspective view so you can see all of the edges surrounding the area for the face shield.
2. Select Edit Mesh > Append to Polygon Tool > .
3. In the Append to Polygon Tool settings window, set the following:
   • Keep new faces planar: Off

   If the planar option is on, the Append to Polygon Tool will not create a multi-sided polygon as the edges you’ll select do not form a planar region.

4. In the perspective view, click once on the top inner border edge of the helmet mesh to indicate which mesh you are appending to, and then click the same edge a second time to begin the append operation (see image below).
5. Click the bottom edge of the face shield that is opposite the first edge you just clicked.

   A polygon appears that spans the two edges.

   

6. Continue to click the remaining border edges in a counter-clockwise direction around the opening for the face shield (see image above) until you reach the last edge.
7. When you are finished clicking the perimeter border edges for the face shield, press the q key to quit the tool.

   The multi-sided polygon is completed and added to the existing mesh. Multi-sided polygons are also referred to as n-gons.

   

Ideally, all faces should be four-sided to match the other faces on the helmet mesh. In the next section, you'll split the n-gon vertically and horizontally into several smaller four-sided polygons using the Split Polygon Tool.