Creasing Subdiv Surfaces


Subdiv surfaces support two types of creasing: Partial Crease and Full Crease. Creasing gives an edge more weight, making it appear sharper. Partial creases use finer display levels to adjust the surface, whereas full creases make edges hard. You can use creasing to add extra detail to an object quickly ( Figure 9.23 ).

Figure 9.23. These balusters were made with subdivs. On the left is the raw shape; on the right is the same shape after using creasing to flesh out the detail.


To add a partial crease:

1.

Choose Create > Subdiv Primitives > Sphere.

2.

Right-click the sphere, and select Edge from the marking menu.

3.

Select the top four edges of the cubic cage ( Figure 9.24 ).

Figure 9.24. Select the top four edges of the cube only.


4.

Choose Subdiv Surfaces > Partial Crease Edge/Vertex.

The surface is refined, and the new components draw up toward the corner ( Figure 9.25 ).

Figure 9.25. Partial creases draw the geometry toward the edge of vertex and also refine the area to allow for the sharper corner.


5.

Without deselecting anything, partial-crease the edges a few more times.

Notice that the surface becomes sharper and more creased but also gets increasingly dense ( Figure 9.26 ).

Figure 9.26. This corner has been creased many times. The result is a nice beveled corner, but it's very dense and may perform slowly.


To add a full crease:

1.

Continue with the sphere from the previous task.

2.

Select the uncreased edges of the cubic cage ( Figure 9.27 ).

Figure 9.27. Use the Marquee Select tool to select the rest of the rest of the cube's edges


3.

Choose Subdiv Surfaces > Full Crease Edge/Vertex.

The edges are sharpened, and the sphere now resembles a tile. Note that the edges don't refine the surface ( Figure 9.28 ).

Figure 9.28. The full creased edges are as sharp as a normal poly edge and don't require refinement of the model.


4.

Select the middle edges of the tile.

5.

Choose Subdiv Surfaces > Uncrease Edge/Vertex.

The tile now looks like a cylinder ( Figure 9.29 ).

Figure 9.29. With the sides uncreased, the surface smoothes back into a cylinder in the vertical direction.


Tips

  • You can also crease vertices. This technique is useful for filling corners between creased edges or pulling spiky geometry smoothly from a surface ( Figure 9.30 )

    Figure 9.30. This silly face was made with full and partial creases. Vertices were pulled out of the head and creased to make the hair spiky.

  • If you use Partial Crease Edge/Vertex more than a few times, the dense geometry added from the multiple creases can cause significant slowdown. To make a corner sharper than what one or two creases provide, you can instead add detail to the poly cage as you would for a smooth proxy.





Maya 7 for Windows and Macintosh(c) Visual Quickstart Guide
Maya 7 for Windows & Macintosh
ISBN: 0321348990
EAN: 2147483647
Year: 2006
Pages: 185

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