MODELLING CONCEPTS

 

NURBS, Non-Uniform Rational B-Splines, are mathematical representations of 3D geometry that can, through the positioning of control points on a rectangular surface describe shapes with a very high level of fidelity.

 

We have moved away from nurbs in the 3D packages which create and animate models in the enertainment sector - towards subdivision surfaces.  Occasionally a NURBS object can be a used a good basis for a subdivision cage.

​

NURBS based CAD packages such as the excellent Placticity and Rhino are excellent tools for product design and the resulting surfaces are easily translated by CNC and other manufacturing machinery to create physical objects. Problems arise when the polygonal geometry they create on conversion is required for use in animation, texturing and deformation so we generally do not use them.

 

That said, becuase of their speed of use, they can be used to design props in bigger productions with the understanding that the models will at some point need to be rebuilt by hand for use in a production pipeline.

​

Most of the concerns in NURBS modelling are actually the basis for good subdivision surface modelling technique but subdivision surface modelling allows many more freedoms and the potential to break the rules in order to achieve a shape. - at the expense of mathematical precision required in manufacturing.

​

All of the modern methods to texture, deform and animate meshes are based on subdivision surface modeling and converting between a NURBS object and a Sub-D model is rife with complex problems which have just not been solved yet.

 

Converting a model from a CAD package for use in blender (or any of the other big polygonal modellers) is not a good solution. The resulting mesh will be full of inappropriately placed triangles and poles. To work in blender, you need to learn how to make objects directly in blender.

​

We will not likely concern ourselves with NURBS on this website (but you never know!)

​

​