Best Way to Start 3D Modeling in AutoCAD

For a practical demonstration, check out my stair-building video above. I’ll walk through the process of building walls and stairs in AutoCAD using extrusion and basic 3D techniques.

Why a Good 2D Foundation is Essential

When learning 3D modeling in AutoCAD, starting with a solid understanding of 2D fundamentals is crucial. Mastering 2D is the best way to begin 3D modeling in AutoCAD. While diving directly into 3D might seem appealing, building a foundation in 2D helps you grasp essential concepts such as the Cartesian coordinate system, precise object creation, and command shortcuts—all of which transfer directly into 3D work.

From 2D to 3D in the Architectural World

Thirty years ago, I worked at an architectural firm, creating working drawings for a big residential developer. Back then, we relied on 2D drafting, and to streamline our workflow, I developed a custom routine to build 3D roofs and walls quickly. The primary goal was to create 2D elevations on the fly using 3D objects, saving us time and improving accuracy.

This method allowed us to work more efficiently and laid the foundation for my transition into full 3D modeling. Learning how to create and manipulate 2D geometry helped me understand how to extrude, rotate, and transform objects in 3D space—still a valuable technique in today’s 3D modeling.

Why Start with 2D in AutoCAD?

The best way to start 3D modeling in AutoCAD is by mastering 2D drafting first. Understanding basic input commands and the coordinate system makes learning 3D go smoother. Here’s why:

  1. Grasping the Cartesian Coordinate System: In 2D, you get familiar with X and Y coordinates, which is essential when working in 3D, as the Z-axis is added. By understanding 2D geometry, you can easily manipulate objects in 3D space.
  2. Mastering Input: AutoCAD is known for its accuracy. When you create precise 2D drawings, you can transform those objects into accurate 3D models. This translates directly into clean, accurate 2D and 3D drawings.
  3. Command Shortcuts: If you’ve mastered 2D, AutoCAD’s numerous commands become easier to manage. Shortcuts for commands like L (line), C (circle), and O (offset) carry over to 3D modeling with commands like EXT (extrusion) and SU (subtract), making it easier to build complex 3D forms.By learning these techniques and focusing on the fundamentals, you’ll have the tools to advance your 3D modeling skills.

The Power of Extrusion in 3D Modeling

Learning extrusion in AutoCAD is one of the easiest ways to get started with 3D modeling. With extrusion, you take a 2D shape—like a rectangle or a circle—and pull it into a 3D object. Whether modeling mechanical parts, piping systems, or architectural structures, extruding basic shapes gives you a straightforward method for building 3D models from a 2D base.

In my recent U-shaped 3D stair video, I used extrusion techniques to build walls, floors, and staircases. After drawing the floor plan in 2D, I extruded the walls to create the model. Once the walls were in place, I rotated and placed the 3D walls, and I built this model in about 10-15 minutes. The same extrusion process can be applied in mechanical and architectural projects, as it provides a quick way to visualize 3D space from 2D drawings.

Here’s a breakdown of the steps I followed in the video:

  1. Draw 2D/3D exterior walls and floor
  2. Use AEC tools to build the stairs rapidly.
  3. Extrude the walls and stairs into 3D objects.
  4. Rotate the walls and refine the layout
  5. Added railings and then created and saved a few 3 views

Advantages of Extruding and Rotating 2D Objects in 3D

There are several benefits to starting with 2D geometry and extruding it into 3D objects:

  • Familiarity: Most users are already comfortable with 2D drawing, so using familiar tools makes the transition to 3D easier.
  • Precision: Extrusion allows you to maintain accuracy in your models, especially for mechanical or piping systems where exact measurements are critical.
  • Efficiency: By starting with 2D, you can quickly sketch your ideas and then build them into 3D forms, saving time in the design process.

Direct 3D Modeling vs. 2D-to-3D

While some CAD software emphasizes direct 3D modeling, where users create and modify shapes directly in 3D space, AutoCAD still shines with its hybrid 2D-to-3D workflow.

Tools like Mech-Q for piping and mechanical design and the AEC module in AViCAD provide additional benefits. These tools allow you to expedite the drawing process and work well with your CAD workflow. They are also extremely accurate and allow you to work efficiently.

Programs like SolidWorks, Fusion 360, and SketchUp use direct 3D modeling, but they often require significant time to learn their concepts and are very expensive. By contrast, AutoCAD’s extrusion-based workflow lets users gradually transition from the 2D world into 3D.

Mastering 2D is Key to 3D Success.

To truly excel at 3D modeling in AutoCAD, take it from me. Start with a strong foundation in 2D drafting. This is the best way to start 3D modeling in AutoCAD, as it ensures you understand the essential principles of CAD and how to input using various shortcuts. Whether you’re working on architectural, HVAC, or piping, tools like Mech-Q and the AEC module in AViCAD will help you transition smoothly into 3D.

If you’re eager to dive into 3D but feel overwhelmed by the complexity, start with 2D. Learn the basics, practice extrusion techniques, and gradually build your confidence—mastering 2D is the best stepping stone to becoming a 3D expert.

 

 

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