Component selection and transformation is one fundamental method for editing the shape of a polygon mesh. As you model, you’ll find yourself frequently examining and then refining the position of the polygon components (vertices, edges, and faces) while working in the various scene views so they match the reference images on the image planes.

To manually reposition the vertices on the rear of the helmet

1. Right-click the helmet and select Vertex from the marking menu that appears.
2. In the side view, select the pair of vertices at the rear lower edge (see image) by dragging a bounding box around them.
3. In the Toolbox, click the Move Tool.
4. In the side view, click-drag the blue arrow on the Move Tool manipulator towards the right until the vertices are repositioned so that your helmet matches the reference sketch on the image plane.

   

   By moving the vertex as well as the vertex adjacent to it along the axis of symmetry, you ensure that the symmetrical shape of the helmet is maintained. If you move one vertex independently of the other it may result in an unwanted bump or valley in the mesh. These types of anomalies will become more apparent when you copy the completed half of the mesh across the axis of symmetry.

5. Repeat steps 2 through 4 for the other pairs of vertices on the rear of the helmet. Ensure that the edge loops appear smooth in relation to each other.

   When you have finished, the back region of the helmet should closely match the reference image on your image plane.

   

6. In the side view, select other pairs of vertices along the top and front of the helmet and move them in a similar fashion so they match the reference image. Do not reposition the vertices for the top of the face shield yet.
   TipYou can click in the center of the Move Tool manipulator to drag a vertex selection freely.

   

Next, you’ll reposition the border edges that lie along the bottom edge of the mesh. You can select these edge types using the Select Border Edge Tool.

To reposition the lower border edges on the helmet

1. In the side view, select the lowest horizontal edge loop on the helmet by choosing Select > Select Border Edge Tool from the main menu, and then clicking the first and then the last edge on the loop as indicated in the image below.
2. Using the Move Tool, drag the selected edge loop downwards until the left hand vertex roughly matches the lower edge indicated in the reference sketch.

   

3. In the side view, select and reposition the remaining vertices individually on the edge loop using the Move Tool so they match the reference sketch.

   

   NoteUp to this point in the lesson, you’ve been instructed to reposition the vertices on the helmet mesh only within the side view (Y, Z plane). Once you achieve the shape you want in the side view you will then concentrate on how the model appears when viewed from the front and perspective views.

To edit the border edges on the upper edge of the face shield

1. From the Select menu, choose Select Border Edge Tool.
2. In the side view, click the first border edge that will be used as the upper edge of the face shield, then click the last border edge (see image).

   The border edges in between are selected.

   

3. In the Toolbox, select the Rotate Tool by clicking its icon.
4. In the side view, click-drag the rotate manipulator in a clockwise direction until the border edges are rotated at roughly the same angle as the corresponding edge in the reference sketch.

   

5. With the border edges still selected, click the Move Tool again and drag the green manipulator upwards to match the location of the border edges in the reference sketch.

   

6. Reposition the pairs of vertices on the upper front of the helmet to match the reference sketch.

   

At this point in the lesson, the outline of your helmet should roughly match the helmet in the side view reference image. If it doesn’t, review the earlier steps in this lesson and make any adjustments to your polygonal mesh as required.

If you view your helmet in the front orthographic view, you’ll notice that the helmet shows a wider profile from this view than the reference sketch. In the next steps you’ll correct this using the front and top orthographic views of the helmet for reference.

To reposition vertices on the side of the helmet to match the sketch

1. Display the front view.
2. In the front view, select the vertices that extend beyond the outline of the helmet as shown in the reference sketch (see image).

   

3. In the front view, move these vertices to the left until they match the widest area of the helmet in the reference sketch (see image).

   

When you view your helmet from the top orthographic view the region between the side and rear of the helmet appears a bit flat in relation to the other areas. To correct this you can move the other vertices in this region outwards in a similar fashion so the curvature in this area appears fuller and more rounded. However, viewing only from the orthographic views can be limiting, and you should also use the perspective view to examine the mesh.

To examine the mesh using the perspective view

1. Enlarge the perspective view.
2. Dolly and tumble the perspective view while you closely examine the helmet mesh.

As you examine the vertices along any particular edge loop, the vertices on the mesh should appear to cascade in a smooth gradual fashion to create the curvature of the mesh with no undesirable spikes or dips.

Ensuring that the mesh appears relatively smooth at various stages throughout the modeling process will reduce the possibility for issues when you create a high resolution version of the mesh later on.

If you find areas where one vertex (or more) appears to protrude outwards (or recedes) on the mesh in relation to neighboring vertices, you can correct these protruding regions by repositioning the affected vertices in the perspective view.