3D modeling has changed how we see products and designs. However, 2D drawings are still the major form of communication in any construction site or factory. Therefore, understanding how to successfully convert from a 3D AutoCAD drawing to a 2D AutoCAD drawing is an essential skill to have in order to successfully create professional technical documents based on your detailed models.
When correctly flattening out your geometry, you will avoid hours of redundant redrafting of your work when preparing Millwork Shop Drawings or Architectural Plans.
The Three Primary Conversion Methods
There are only three major options available for converting a 3D drawing into a 2D drawing. Depending on whether you are creating a dynamically linked layout or a static block, you have to choose the right tool for the job.
1. The FLATSHOT Command
A good tool for quickly exporting a 2D representation of your 3D element from Model Space is the FLATSHOT Command. The FLATSHOT command is one of the most frequently used tools in AutoCAD for generating 2D blocks created from 3D models. The FLATSHOT command will provide a two-dimensional view of any visible elements within the 3D model and can output in a dynamic way based on how the 3D element appears on the drawing.
- Best for: The FLATSHOT command is excellent for producing 2D images from within Model space.
- Key Features: The ability to control how hidden lines appear is also a feature that many users take advantage of, as they can display the hidden line as a dashed line or completely remove them from the drawing, allowing the user to create cleaner-looking technical documents.
2. The VIEWBASE Command
If you want an automated and more premium solution, then VIEWBASE is your best choice. It outputs the associative projected views (Top, Front, Side, and Isometric) in Paper Space.
- Ideal For: Comprehensive 2D Drafting Services for Architectural Projects.
- Key Feature: The 2D Views within your layout will automatically update if you make any changes to the original 3D Model.
3. SOLPROF, SOLVIEW, and SOLDRAW
While they may not be as advanced as VIEWBASE, these commands remain important for users who continue to use Legacy Workflows or who have Very Specific Solid Modeling Requirements. SOLPROF is the command used to create profile lines of 3D Solids, making it easier to produce 2D documentation of those profiles.
Step-by-Step Conversion Workflow
To ensure a smooth transition from AutoCAD 3D to 2D, it is important to follow this standard workflow:
- Preparation of Model: Before performing the conversion, it is recommended that you perform an audit on the 3D Model you will be converting. Remove any unneeded geometry and PURGE any layers or blocks that were not used. (A layer or a block can be continued to be used for many future projects).
- Set the View: Use either the View Cube or If you would like your model to appear as you would like the 2D output to appear, orient your model the way you want to it to appear.
- Issuing the Command:
- Type in “FLATSHOT” in the Command Line.
- Select “Insert as New Block” from the dialogue window.
- Change the Obscured Lines settings according to your preferences.
- 2D Block Placement and Scale: Place your new 2D block in your drawing. Check the AutoCAD conversion from the 3D Model to the 2D Block is at a 1:1 scale for accuracy when creating CAD Shop Drawings.
- Refine with OVERKILL: Use the OVERKILL command to refine your new 2D geometry so that all duplicate or overlapping lines, which may exist due to the flattening process, are now removed.
Best Practices for Professional Results
When presenting a professional drawing, you will need to do much more than run a single command:
- Layer Maintenance: Create a dedicated “2D-Output” layer to output your 2D geometry to. This helps reduce the chances of your 3D components creating a disorganized 2D workspace.
- Line Weight Standardization: A 2D drawing will be developed based on the lines that make up the components of the drawing. Assigning different weights to “Visible” vs. “Hidden” lines is important to enhance the legibility and clarity of 2D drawings.
- Utilization of External References (Xrefs): Xrefs are a great method to combine many drawings from large projects into one cohesive sheet, as opposed to storing everything in one large file.
- Accuracy Verification: When creating FF&E drawings, please ensure that all measurements are verified immediately following the conversion process. Dimensional verification will protect against the complication of “foreshortening” due to mistakes in the User Coordinate System (UCS).
Troubleshooting Common Issues
Even professionals can have difficulties when using AutoCAD to change from 3D to 2D. Here are solutions to some of the common mistakes:
- “My 2-D output appears to be off-kilter.” This can happen when the User Coordinate System (UCS) is not set to the World Coordinate System before you attempt the conversion. Type UCS > World, select World, and then repeat the conversion process.
- “I can’t see any hidden lines.” You may have to access your FLATSHOT options to make sure that under Obscured Lines, you have checked Show and that the type of line chosen is something recognizable (for example, a dashed type).
- “My file is too large.” High-poly meshes will generate thousands of tiny 2D lines as output. You should either reduce the 3D model to a lower polygon count and/or outsource the task to an AutoCAD drafting service that specializes in optimizing the conversion process.
Conclusion
Converting your AutoCAD files from 3D to 2D provides an important link in transforming your conceptual design into a building that can actually be built. By mastering the tools in AutoCAD, such as FLATSHOT and VIEWBASE, you will be able to provide technical drawings that are accurate, easy to read, and create a polished representation of the finished product.
All your projects rely on accurate conversions as the foundation of any project. The conversion process, whether depicting furniture in detail or designing a large-scale building, will be dramatically affected by whether you take the time to do an accurate conversion.
