1. Introduction
(seamless modeling in Maya)

"This tutorials is result of my research work in the area of character modeling and animation."
Michael Bazhutkin is animator of video studio at Soros Foundation-Kyrgyzstan
web site: www.geocities.com/bazhutkin
e-mail: misha@soros.kg



Click on pictures for view of big pictures.



Maya file with samples:
blend.zip<\/a>


2 NUBS objects



CVs and Hulls are visible



selected faces before deletion



polygonal surface after combination



polygonal surface after smoothing


Sometimes we need to have the seamless character model. But we see that for animation of the organic forms NURBS model should be used rather than polygonal one. As the practice showed during animation of the character, such tools as Stitch, Blend, and Fillet work slowly and not always correctly.

I have found one method which can solve this problem. But this method is hard, because Maya has not necessary special tools. This method is similar to that modeling method of head in Bingo film, where the Stitch tool was used, where the model is made from multisurfaces.

I found that if a degree 2 NURBS surface was converted in polygonal surfaces with using Quads & Control Points method and then was smoothed by the Smooth tool or was converted in subdivision surface, Its curvature will be the same. So to create seamless model, it is necessary to complete the following:

1. Create of degree 2 NURBS surfaces, which have identical coordinates of extreme points. In order to gain such result you can build the surface by using curves and such modeling tools as Boundary, Extrude, Revolve etc. To edit the surfaces Artisan brushes can be used. To get the coordinates of surfaces and curves end points to match I have used �Snap to Points� mode. Assign materials to all surfaces.
2. Convert all NURBS surfaces into polygons (Quads & Control Points method). If the normals� surfaces directed into the different sides (use the Back Face Culling mode to test it), you need to make a reversion of these normals� surfaces. And to escape the problems with mapping of textures you need to select all of the faces and apply Edit Poligons/Texture/Normalize UVs. Select all polygon objects and then combine them up to one object. In this stage we make our model as seamless surface using such tools as Merge Edges, Merge Vertices or Merge Multiple Edges. And now if we use Smooth Tool we have seamless model of same curvature as initial NURBS surfaces. Using this method it�s easy to make characters of any complexity, ignoring necessity to use subdivision surfaces.

The advantages of this method are:

1. Seamless model with NURBS quality.
2. High control of a curvature of model at a stage of modeling and during animation process.
3. Having the same mapping of textures as of NURBS. The truth is in converting periodic NURBS (such as an orb, cone) textures� mapping will be disturbed. (reason is unknown). To correct this it is necessary to convert periodic NURBS into closed type - use detach operation.
4. Realtime playback animation of polygonal model without smoothing.
5. Control of detailing of final model.