The 3DCheapskate's Brief Guide To Modelling Software
Modelling software lets you create your own models of 3D objects from scratch. They can be saved in a variety of file formats, and many of these can be imported into other 3D software. Since I use Blender for all my modelling I know very little about any of this software, so all I can do is cover some of the very basic generic stuff and give you some links to help you download some modelling software.
The main paid modelling software I know of is Carrara, Hexagon, and Sculptris.
The Renderosity 3D Modelling forum header gives the following advice for the question "What 3D Program Should I buy?":
"Not one person here can really tell you what's best for you, as everyone has their own taste in workflow. Try the demo or learning edition of the program you're interested in, this is the only way to find out which programs you like."
A Generic Overview Of Modelling Software
What Is A 3D Model?
All computer 3D models are made up of three-dimensional surfaces. The surfaces can be flat like a sheet of paper, or curved. Each surface is 'controlled' by a set of points (vertices). In 'mesh' modelling they are the corners of the faces. In NURBS (Non-Uniform Rational Basis Spline) modelling (which I know nothing about) they are the control points for the curved surfaces.
How Is A 3D Model Stored?
The simplest answer is that it can just be stored as plain text. The Wavefront Object (OBJ) format is a good example - here's a model of a cube:
# Blender3D v249 OBJ File: # www.blender3d.org mtllib redbox.mtl v 1.000000 -1.000000 -1.000000 v 1.000000 -1.000000 1.000000 v -1.000000 -1.000000 1.000000 v -1.000000 -1.000000 -1.000000 v 1.000000 1.000000 -1.000000 v 0.999999 1.000000 1.000001 v -1.000000 1.000000 1.000000 v -1.000000 1.000000 -1.000000 usemtl CubeMaterial s off f 1 2 3 4 f 5 8 7 6 f 1 5 6 2 f 2 6 7 3 f 3 7 8 4 f 5 1 4 8
And here's the material for the cube's surface:
# Blender3D MTL File: # Material Count: 1 newmtl CubeMaterial Ns 96.078431 Ka 0.000000 0.000000 0.000000 Kd 0.800000 0.000000 0.000000 Ks 0.500000 0.500000 0.500000 Ni 1.000000 d 1.000000 illum 2
How Do You Edit 3D Models?
Even though models can be stored as text files you don't edit those text files directly. You use some 3D software that puts the object in an imaginary 3D world and lets you move the viewpoint around.
There are two main approaches that 3D modelling software uses: One is to let you manipulate the vertices directly; the other is to let you treat the model as a lump of clay and 'sculpt' it. Some software uses the first approach, other software uses the second, and yet other software allows you to use both approaches.
Anim8or is suggested on the Renderosity 3D modelling forum.
Carrara from DAZ3D is targeted more at 3D professionals.
MarbleClay is suggested on the Renderosity 3D modelling forum.
Metasequoia is suggested on the Renderosity 3D modelling forum.
Moray is suggested on the Renderosity 3D modelling forum.