3D object represent with primitive shapes

[shanky]

Hi,
Given a 3D object in R³ space can we represent it using three basic primitive shapes like Sphere, Cone and Cylinder? Would this claim be valid?

 

[Orodruin]

No.

 

[shanky]

No.

Hi Orodruin,

Can you be more clear. Why No and isn't it write to represent 3D objects into any primitive shapes.

 

[Orodruin]

It is not very clear what you mean by "representing 3D objects into primitive shapes".

 

[shanky]

It is not very clear what you mean by "representing 3D objects into primitive shapes".

I am trying to decompose 3D object (eg. Bunny) into primitive shapes basis functions.

 

[Nidum]

Depends on whether you mean in a strict mathematical sense or in a practical representation sense .

(1) Real 3D objects of great complexity can be accurately represented by assemblies of simple units like tetrahedrons . This is one of the basic principles of finite element analysis and some types of 3D CAD .

Tetrahedrons and other primitive shapes like cubes can be used in a basic way or they can be systematically deformed to give a higher level of accuracy .

Some examples : http://www.truegrid.com/fe.html

(2) At a more artistic level complex 3D shapes can be represented by assemblies of basic units taken from a big selection of basic units - anything from simple cubes to arms, legs bugs and spaceships . Again these objects can be deliberately distorted as required .

Fun to play with : https://www.tinkercad.com/