HA4 Task 4 - Mesh Construction

How are 3D models constructed? Describe and explain the different modelling techniques available to a 3D designer.

Remember that you are trying to comprehensively explain the theory and applications of 3D with elucidated examples and consistently using subject terminology correctly.

_________________________________________________________________

Polygonal Modelling

Polygonal modelling involves using polygons to represent a surface and create a 3D object.  

http://en.wikipedia.org/wiki/Polygonal_modeling

image from http://www.cc.gatech.edu/home/turk/vimp/index.html

_______________________________________________________________
  

Primitive Modelling

Primitive modelling is a common method of creating a polygonal mesh is by connecting together various primitives, which are predefined polygonal meshes created by the modeling environment. Common primitives include: 

3D - boxes, cylinders, pyramids and torus, sphere and the wedge

2D - circles, squares, triangles

http://en.wikipedia.org/wiki/Polygonal_modeling

image from http://www.webreference.com/3d/cararra/3.html

______________________________________________________________

Box Modelling

box modelling is a more popular modelling method, it uses two tools:

The subdivide tool - splits faces and edges into smaller pieces by adding new vertices.

The extrude tool - when applied to to a face, or grou[p of faces, it creates a new face of the same size and shape which is connected to each of the existing edges by a face.

http://theorangeduck.com/page/subdivision-modelling

image from http://southerngfx.co.uk/wp-content/uploads/2010/11/3box.png

______________________________________________________________________

Extrusion Modelling

Extrusion is a method in which the user creates a 2d shape which traces the outline of an object from a photograph or a drawing. The user then uses a second image of the subject from a different angle and extrudes the 2d shape into 3d, again following the shape’s outline. This method is especially common for creating faces and heads. In general, the artist will model half of the head and then duplicate the vertices, invert their location relative to some plane, and connect the two pieces together. This ensures that the model will be symmetrical.



http://forum.thegamecreators.com/?m=forum_view&t=93981&b=3