This tutorial covers the modeling of a sci fi creature head using the popular technique of NURBS patches. Models consisting of NURBS patches is the most common appearance used in films, based on several reasons: NURBS can have infinite resolution, meaning it retesselates depending on distance from camera, based on curvature etc. This feature also makes displacement mapping really useful, since the NURBS surface can be tesselated depending on the look of the displacement map, and put detail where needed thus optimizing memory usage and render speed. NURBS also generates mapping coordinates, so if the object would be "well" modeled i.e. with evenly spaced isoparms, you would be able to paint (using a 3d painter) on the surfaces with perfect result and no need for mapping gizmos.

These were the advantages. Since NURBS patch models used in films mostly are scanned in using a 3d digitizer, the actual 3d modeling isn't required, only cleaning up the resulting data. The workflow of patch modeling from scratch in a 3d application can sometimes be a bit slow in comparison to polygons, but as always, with training you will become faster.

The most important thing about patch modeling is how you place the patches, which requires planning before start. The next most important thing is being sure they have the same parameterization and directions. The tutorial also covers how to make the surfaces evenly parameterized.

Modeling a creature head

I made a rough sketch which I will use as reference material for the model, see



Bring the image into Photoshop or alike, and in a new layer, paint lines which will represent the curves. This part of the modeling process is by far the most important one! You don't want to do anything wrong here because then you most likely will have to rebuild the cage later on. Avoid areas where 6 patches meet, this is a no-no. And whenever you can rebuild a 5 patch meeting area into a 4 patch meeting area, do not hesitate because tangency between the patches is easier to achieve, and it animates better. What I found to be a decent cage setup is shown in



There are a lot of ways to setup a curve cage, but in my opinion it's more important to make the cage as close to the reference material as possible, even though it might generate more patches. So even though it's a general rule to keep the amount of patches to as few as possible to easify animation and texturing, make sure it doesn't get to the point that you cut down on design.

(Areas like the inner nostril, the eyelids and inner mouth are not all visible in the line drawing, it will be covered later on.)

What you will start with now is using the curve tools in Maya, building a cage of curves that will form the surface. The rule here is to use as few points as possible in the beginning, so you won't have to pull an unnecessary amount of points when shaping the basic appearance.

Step 1.

Start up Maya, in the menu or hotbox go -Window -Outliner. Select the Side camera and hit Ctrl+A to see its attributes. Scroll down to 'Environment' and hit 'Image Plane' create button and browse to your reference image file.



Step 2.

Next, go -Create -Cp curve tool, and create curves where you have drawn the lines - see



Each side of the later-to-be-patch is one unique curve. Hold C while drawing another curve to have the first curve point snap at the previous curve, and when releasing, make sure it's at the end of the curve you snap to, so the curves meet perfectly.

At this point it isn't important to have the curves at the same number of points, that is a later issue. One thing to aim at though is to keep the amount of points at each curve as low as possible, so that when you pull them out to form a 3d curve cage you simply have less points to shape with.



The picture above shows all the curves layed out. Remember it's not all the necessary curves, but the few left will be done later.