Issues of Wire-frame Model:

The solid modelers are powerful representations and they must procedure the following issues :

Domain

Whereas no representation may describe all possible solids, a representation must be able to represent a useful set of geometric objects.

Unambiguity

While you see a representation of a solid, you shall know what is being represented without any doubt. An unambiguous representation is generally referred to as a complete one.

Uniqueness

That is, there is just one way to represent a particular solid. If a representation is unique, then this is easy to determine if two solids are identical since one may just compare their representations.

Accuracy

A representation is said precise if no approximation is required.

Validness

It means a representation should not produce any invalid or impossible solids. More precisely, a representation shall not represent an object that does not correspond to a solid.

Closure

Solids shall be transformed and utilized with other operations such as union and intersection. "Closure" means that transforming a valid solid always yields a valid solid.