Creating a subdivision surface

Subdivision Surfaces Lesson 1: Introduction
In this lesson you learn some of the basic tools for working with subdivision surfaces as you model a
human character's hand.

In this lesson, you learn how to:
 Convert a polygon surface to a subdivision surface.
 Work with subdivision surfaces in Polygon Proxy Mode.
 Split subdivision faces to create areas for more detail in a model.
 Extrude the split faces to create fingers on the hand.
 Work with subdivision surfaces in Standard Mode.
 Change the Display Level when working in Standard Mode.
 Add more detail to subdivision surface models using Refine Selected Components.
 Create a crease along a vertex edge.


Creating a subdivision surface

You begin the lesson by creating a polygonal cube. You'll convert this cube to a subdivision surface that
will be the foundation of the hand. The reason for starting with a polygonal surface and converting it to a
subdivision surface is that you can thereafter edit the object's shape with more versatility. You can edit
with subdivision surface tools and polygonal tools.



To create a polygon cube
1. Select Create > Polygon Primitives > Cube > . In the options window, select Edit > Reset
Settings. Then enter the following values and click the Create button.
o Width: 8
o Height: 2.5
o Depth: 8
The resulting polygonal cube is roughly proportional to the palm of a hand.


To convert a polygonal cube to a subdivision surface

1. To convert the polygonal cube to a subdivision surface, select Modify > Convert > Polygons to
Subdiv.

2. Press 3 on your keyboard (to select Display > Subdiv Surface Smoothness > Fine).
3. Press 5 (to select Shading > Smooth Shade All).

With the Smoothness set to Fine, you can see that the conversion to a subdivision surface
creates a rounded, smooth shape. By pressing 3, the subdivision surface is displayed more
precisely in the scene view. This gives a closer approximation of what the surface will look like
when you create a rendered image of the scene.
As an alternative, you could have chosen a rough smoothness (press 1) so that Maya processes
your editing changes in the scene view more quickly. Regardless of the smoothness in the scene
view, surfaces always are displayed precisely in rendered images of the scene.

To display a subdivision surface in polygon proxy mode
1. Select Subdiv Surfaces > Polygon Proxy Mode.


The wireframe cube looks the same as the original polygonal cube. The new cube is called a
polyToSubd1 for the subdivision surface as a result of the conversion. Rename it LeftHand. You
can use polygonal modeling tools to edit the shape of the polygonal proxy, which indirectly alters
the shape of the subdivision surface. Unlike working with an actual polygonal object, your
modifications result in perfectly smooth surface changes rather than faceted changes.


Splitting a surface in polygon proxy mode

Next, you use polygonal modeling techniques to split a face into multiple faces to be extruded as fingers.

To split the polygon face into multiple faces

1. With LeftHand still selected, select Edit Polygons > Split Polygon Tool.
You'll use this tool to split the front face of the proxy into several faces to be extruded into
fingers.

2. In the front view, click the point on the top edge as shown in the following figure, then click the
corresponding point directly below it on the bottom edge. If the line between the points isn't
perfectly straight, use the middle mouse to drag the second point to the correct position. Press
Enter (Windows and Linux) or Return (Mac OS X).

This splits the face into two faces. You'll extrude the left face into a finger later.

3. Repeat the preceding two steps as necessary to split the face as follows:


Notice how splitting the face into multiple faces alters the shape of the subdivision surface. The
front part of the subdivision surface now resembles the proxy shape more. If you were to split the
front face several more times, especially near the outer edges, the subdivision surface would
sharpen and resemble the proxy shape even more. More faces means finer control, often at the
expense of making the surface harder to work with.

With the added faces, the subdivision surface looks a bit like the palm of a hand. You'll build upon
this shape to create a left hand with palm facing downward and fingers extruded outward. You'll
extrude the wide faces into fingers, and you'll leave the narrow faces as webbing between the
fingers.







Extruding polygon faces

Next, you'll extrude faces to create fingers for the hand.

To extrude the polygon faces to create fingers

1. In a perspective view, right-click LeftHand and select Face from the marking menu.
This lets you select faces.
2. Select the right-most face by dragging a selection box around the tiny box at its center. (The
subsequent illustration shows which face to select.)
3. Select Edit Polygons > Extrude Face.
4. Drag the blue arrow manipulator outward a little to create the first segment of the smallest finger.
The blue arrow turns yellow when selected.

5. Repeat the prior two steps to create the middle segment of the smallest finger.
6. Repeat the prior two steps once again to create the top segment and complete the finger.
By creating three segments for a finger, you mimic a real finger's natural structure. The borders
between the segments have vertices (not displayed currently) that let you reshape those regions,
for instance, to create knuckles.

7. Similarly, extrude the ring, middle, and index fingers from the appropriate wide faces. Don't
extrude the three small faces that lie between the wide spaces. Leave them in position to allow
for webbing between the fingers.


Note

Do not be concerned if the hand you create does not match the lesson's illustrations. Your goal in this
lesson is to learn the workflow of subdivision surfaces, not to perfect your modeling technique.

Next, you extrude a thumb using similar techniques as you used for the fingers. The following steps are
abbreviated. See the preceding pages for details on the described tools, if necessary.