Creasing and hardening edges on a mesh
 
 
 

You can crease or harden the edges on your polygon meshes. Hardening or creasing the edges sets how the mesh transitions between faces enhancing the realism of your model.

When you harden an edge on a polygon mesh, you change the direction of the normals associated with the shared edge, which in turn affects the shading along those edges. When you crease an edge of a mesh that has an associated subdiv proxy, the edges on the smoothed high resolution version are creased by physically modifying the polygon smoothing surrounding those edges.

In this lesson, you’ll try both methods on your helmet mesh.

To display hard and soft edges on a mesh

  1. Right-click the low resolution mesh, set the selection type to Object Mode, and then select the helmet mesh.
  2. Select Soft/Hard Edges.

    The wireframe mesh on the helmet updates to display both dashed and solid lines. The dashed lines indicate edges that are set to display as soft shaded. The solid lines indicate edges that are set to display as hard shaded. The reason some of the edges are hard and some are soft relates to the particular settings for some polygon tools.

To soften the edges on the mesh

  1. With the low resolution version of the helmet still selected, select Normals > Soften Edge.

All of the edges on the helmet mesh are set to be shaded in a softened fashion. The wireframe mesh updates to display as dashed lines indicating that all of the edges are set to be soft shaded. You may not notice any immediate effect on the smoothed high resolution version, but its important that you perform this step before you proceed to harden specific edges on this model.

To harden the edges surrounding the face shield

  1. Right-click the low resolution mesh and set the selection mode to Edge.
  2. Select the inner edges that surround the perimeter of the face shield (see image below).
    TipYou can quickly select the inner edges surrounding the perimeter of the face shield using the Select Edge Loop Tool. You may need to double-click in a couple of areas to complete the selection.
  3. Select Normals > Harden Edge.

    The selected edges are hardened on the low resolution mesh.

    Notice that the same edges on the smoothed high resolution version of the helmet are unchanged. For edges to display sharp on the smoothed version, you must turn on the Keep Hard Edge attribute.

To turn on the Keep Hard Edge attribute

  1. In the perspective view, select only the smoothed high resolution version of the helmet mesh.
  2. In the Channel Box, in the Inputs section, click the listed proxy to display its attributes.
  3. Set the Keep Hard Edge attribute to On.

    The sharper transition between the face shield and the rest of the helmet now appears on the smoothed high resolution version.

  4. Select all of the edges for the grill vents and harden them as well.

To crease edges on the mesh

  1. Select the lower outer edges on the face shield (see image).
  2. Select Edit Mesh > Crease Tool.
  3. In the scene view, press the middle mouse button then drag the mouse to the right to add a crease to the selected edges.

    A thick line appears on both the low resolution model and the high resolution version to indicate that a crease has been applied. Notice on the high resolution version that the related edges have become sharper in appearance, but not as sharp as if they were hardened using the Harden Edge feature.

  4. Save your work.
    NoteYou can toggle the creased edge display (thick lines) by selecting Crease Edges.

Your model is now complete. Depending on your requirements you can delete the construction history on both the low resolution and high resolution versions.

Refine any regions on the helmet as required to gain more experience with the tools presented in this lesson.

If you need to work with either version of the model separately you can ungroup the two meshes by selecting the top node of their hierarchy in the Hypergraph window ( Window > Hypergraph: Hierarchy) and selecting Edit > Ungroup.