2D to 3D Comparison

Geometry driven vs. dimension driven design

2D AutoCAD	3D Autodesk Inventor
You create geometry and then place dimensions. When you change existing geometry, associated dimensions update.	You sketch a part and then control the exact size and shape by changing the dimension values. To change the length or height, you change the dimension values. You manage change within that sketch by modifying the dimension values rather than modifying the geometry.

UCS icon vs. 3D indicator

2D AutoCAD	3D Autodesk Inventor
The UCS icon helps you visualize the orientation of the drawing plane. It provides a movable coordinate system for coordinate entry, planes of operation, and viewing. Most AutoCAD geometric editing commands are dependent on the location and orientation of the UCS. Objects are drawn on the XY plane of the current UCS.	A 3D indicator represents the X, Y, and Z axes. The red arrow indicates the X direction; green indicates Y; and blue indicates Z. However, you do not need to rely on the 3D Indicator much, and you do not need to define snap and grid settings or origin points. You do not need to use coordinates when you draw.

Constraints

2D AutoCAD	3D Autodesk Inventor
You do not use constraints or create relationships between primitives-based models. Changing one primitive has no impact on another primitive.	When you have components to assemble, you place constraints or "rules" on those components to restrict their movement. Autodesk Inventor has six different 3D assembly constraints that determine how components in your assembly fit together and how they move: Mate, Angle, Tangent, Insert, Rotation, and Rotation-translation.

File types

2D AutoCAD	3D Autodesk Inventor
You work with one file type: DWG. This DWG file contains paper space, model space, 2D, and 3D. You cannot separate your model from your drawing, or work separately in 3D. All components of your work exist in the same file.	You work with a minimum of four file types. Multiple file types are advantageous because you can work separately on a part, an assembly, or in a drawing file. Multiple users can work on the same design at the same time. Any changes associate and update in all other files.

Dimensions

2D AutoCAD	3D Autodesk Inventor
To dimension in AutoCAD, you add measurement annotations to a drawing. You place these dimensions on a layer. Basic dimensions in AutoCAD include linear, radial, angular, ordinate, and arc length. You can also create dimensions that are associative, nonassociative, or exploded.	You can place dimensions on layers when used with drawings. There are four basic dimension types that are used differently as you design: model dimensions, reference dimensions, sketch dimensions, and drawing dimensions.

Views

2D AutoCAD	3D Autodesk Inventor
For each drawing, create each individual view of your model. It can be tedious if you have more than one view.	You can automatically generate all the projected views for a model, including section, auxiliary, and broken views.

Boolean operations

2D AutoCAD	3D Autodesk Inventor
You have specific commands to create Boolean operations between different solids (union, subtract, intersect).	You place the parts in an assembly, and then derive the assembly into a single part, while applying the Boolean operation of your choice.

Reuse of data and external files

2D AutoCAD	3D Autodesk Inventor
To avoid file bloat and reuse recurring data like library elements or standard parts, you typically use blocks. Write them out to a file (WBLOCK), and reuse them as external references (XREFS).	You typically set up a project file with a library path and place existing part files and standard files in an assembly. Autodesk Inventor assemblies, by design, store little data into the assembly file. Most of the data is stored in the external part files.

Scale and mirror

2D AutoCAD	3D Autodesk Inventor
There are specific scale and mirror commands that work on both 2D and 3D geometry.	The scale and mirror commands work on 2D geometry. To scale or mirror a single 3D part, you derive the part. You can also mirror individual features or the entire 3D part without using the Derive command.

Selection and grips

2D AutoCAD	3D Autodesk Inventor
You can window select both 2D/3D geometry and use grips to stretch, move, rotate, mirror, and scale.	You can window select 2D geometry and select vertices and segments to move and stretch geometry. To select 3D geometry you use the "Component selection" command. Because Autodesk Inventor has a model browser, alternatively, you can select parts in the browser. For operations like rotate, use the dedicated command.

Styles and layers

2D AutoCAD	3D Autodesk Inventor
You have access to layers, text styles, and dimension styles throughout the product.	Text styles, dimension styles, and layers are available in the drawing environment. Material appearance and light styles are available in parts, assemblies, and presentations.