SAP PLM - SAP Product Lifecycle Management (SAP PLM) application provides you with a 360-degree-support for all product-related processes - from the first product idea, through manufacturing to product service.
TurboSquid - TurboSquid offers 3D models for professionals.
PTC Windchill - Windchill offers breakthrough Product Lifecycle Management (PLM) capabilities, unleashing more data to more stakeholders throughout your organization through a single source of truth for product data and processes.
STLFinder - The 3d models search engine.
Autodesk Vault - Autodesk Vault is a product lifecycle management solution integrated with other Autodesk Products such as Inventor Professional, AutoCAD Electrical, and Mechanical and Civil 3D products.
3DOcean - 3D Models & Accessories From $1 for 3D Models, Textures, Materials & Shaders, 2D Concepts...