3D Modeling

SketchUp Pro
Easy, fast 3D modeling compatible with Google Earth

Rhino
Restrictions
This trial version is completely function, it even allows you to add plug-ins. The limitation is in the number of times you can use the save option, a total of 25 times.

Blender
Great 3D modeling and animation tool

ZModeler
One of the best 3D modeling tools

Looxis Faceworx
Generate 3D model of a face from two photographs

Tutorial para Blender
Complete tutorial for the famous 3D modeling program

MilkShape 3D
Restrictions
30 day trial period.

3DField
Restrictions
Does not print 3D representations.

3DVIA Shape
Design and model in 3D almost like an expert

AC3D
Restrictions
14 day trial version.

Anima8or
Start getting started in the world of 3D animation

Art of Illusion
Java application for 3D modeling, rendering and animation

AutoQ3D
Free software for computer-aided 3D design

Bixorama
Restrictions
The trial version add as watermark.

Blender Portable
Effective 3D modeling program, now in portable version

BodyPaint 3D
Restrictions
15 days trial version

Bryce
Create spectacular 3D landscapes quickly

EarthSculptor
Sculpt landscapes in 3D and color them

Euler 3D
Note
although the program is free, no limit on the author's website you can enjoy it without the need to register.

Flow Architect Studio 3D
Restrictions
Free for non-commercial use.