Marks the selected points (vertices) or edges of a polygon mesh control hull as "hard," creating creases or sharp edges in the corresponding subdivision surface. This is similar to the Set Edge/Vertex Crease Value Property Editor but does not let you control the degree of the effect.
To apply: Select one or more points or edges on the control hull of a subdivision surface, then choose Modify 
Component Mark Hard Edge/Vertex from the Model menu.
To redisplay: Select the control hull, then choose Edit Properties Modeling Properties from the Edit panel and click the Mark Hard Edge/Vertex tab.
