• ARCAD 3D
• BricsCad
• DraftSight: Software gratuito 2D
• FREEdraft2D: open-source CAD
• lignumCAD
• LinuxCAD: CAD & Diagrams for Linux
• OpenCascade: Open Source 3D Modeling Kernel (Desarrollo)
• QCAD: Free open-source 2D CAD system for Linux

AutoCAD / AutoLISP

• 5 Alternativas Libres y Gratuitas
• AulaClic: Curso de AutoCAD 2015  
• AutoCAD 2016
• AutoDESK
• AutoLISP: Técnicas y Recursos de Programación
• CADalog
• CADInstitute
• Civil 3D: Obra Lineal
  • Manual Básico - UNFV
  • Road Design Basics - Civil 3D 2009
  • Training & Support
  • Vídeo Tutorial Civil 3D
• Cursos de AutoCAD desde La Web del Programador
• Curso de AutoCAD 2015: 2011/2012, 2013
• Guía de AutoCAD 2000
• Industrial Solutions
• Introducción al entorno y forma de trabajo en AutoCAD
• OCW UNICAN - Diseño Asistido por Ordenador
• Respuestas a problemas habituales de AutoCAD  
• Sólo Arquitectura:

SmartSketch / Imagineer

• Intergraph Corporation
• Product Info

MicroStation

• Bentley
• Documentación y Soporte Técnico
• Microstation

PTC/CREO (Antes Pro/Engineer & Pro/Mechanica)

• Creo Community
• Parametric Technology Corporation

BIM: Building Information Modeling

• AEC Magazine: BIM for Architecture, Engineering and Construction
• Autodesk:
  • BIM Curriculum
  • Revit
  • Seek: high-quality BIM models
• BIM Object: free 'real world' BIM components
• CadSoft Envisioneer
• GraphiSoft ArchiCAD
• National BIM Library
• Nemetschek Allplan
• Parametric Components: Free 3d models
• Polantis: Real world BIM models
  • IKEA
• Revit City: Tutorial, Families and Support
• Revit Structure Blog
• SoftPlan
• Tekla Structures & BIMsight: Campus
• Trojaola & Liste: Bim Consulting
• Wikipedia

Conversores de formatos 3D

• Accutrans 3D
• Breeze Designer (Copia Local)
• Spinfire 3D CAD2CAD Translator

Publicaciones

• AutoCAD Magazine
• Cadalyst Magazine
• CAD Digest
• CAD User
• Machine Design
• MCAD Café

Otros Recursos

• 3D CAD World: 3D CAD News
• ARQ Web: Arquitectura, Construcción y Diseño
• Ashlar Vellum
• Autodesk Digital Steam: Think like a designer.
• BitCAD: la alternativa económica en CAD
• Cad Blocks Free: 2D & 3D CAD Library
• Cad/Cam Developer's Kit/3D
• CADdy: España
• CADkey
• Catia
• CoCreate: Now PTC Creo Elements/Direct
• Delcam
• DraftSight: Software gratuito 2D
• IntelliCAD Technology Consortium
  • Catálogo de Soluciones
• Manufacturing.NET: The Manufacturing e-Marketplace
• MCAD Central: for Mechanical CAD Professionals
• MCAD Forums
• MCS: Anvil Express
• Nemetschek Vectorworks
• Resilient Modeling
• SDRC: I-DEAS
• SolidEdge
• SolidWorks
• TenLinks.com: Directory of CAD, CAM, CAE
• Unigraphics
• World CAD Access Blog

• DMOZ Resources
• Yahoo! Resources