You can take the trial here 
http://usa.autodesk.com/adsk/servlet/mform?siteID=123112&id=11384226
and activate with the crack. Both x32 and x64 works fine

The Autodesk® Inventor® product line provides a comprehensive and flexible set of software for 3D mechanical design, product simulation, tooling creation, and design communication that help you cost-effectively take advantage of a Digital Prototyping workflow to design and build better products in less time.

Autodesk® Inventor® software allows you to safely integrate AutoCAD® and 3D data into a single digital model to create a digital prototype of the final product. Because the Inventor model is an accurate 3D digital prototype, you can optimize and validate your designs digitally before creating a physical prototype.

Features:

3D Mechanical Design
Layout and system design
Plastic part design
Sheet metal part design
Assembly design

Design Communication and Data Management
Design & manufacturing documentation
3D Visualization & design communication
Data management

CAD Productivity Tools
AutoCAD® integration and DWG™ interoperability
Native translators and data exchange
Learning resources
Customization & automation