How to Flatten CAD Drawing?

Understanding the Flatten Command in CAD Software

Flattening a CAD drawing is the process of converting a complex 3D model into a 2D representation. This step is essential when you need to prepare drawings for presentation or printing. The flattening operation ensures that all elements of the drawing—such as layers, colors, and object types—are maintained as closely as possible to their original state.

Steps to Flatten a 3D CAD Drawing

1. Open Your Drawing: Start by launching your CAD software and opening the 3D drawing that you want to flatten.

2. Select the Objects: Use the selection tool to highlight all the objects in the drawing that you wish to flatten. Ensure that you’ve selected everything that needs to be converted to 2D.

3. Access the Flatten Command:

   • If you’re using the command line, type FLATTEN and press Enter.
   • Alternatively, navigate to the Modify panel and look for the Flatten Objects option, typically found under the Drafting tab.

4. Execute the Command: Upon activating the flatten command, the software will prompt you to confirm the selection of objects if you haven’t done it already. Confirm your selection and follow any additional prompts.

5. Check the Flattening Options: Depending on the software, you may have options to retain certain properties of the objects. Choose the settings that best fit your needs to ensure that layers, colors, and linetypes are preserved.

6. Review the Result: After executing the flatten command, take time to inspect the new 2D drawings closely. Verify that all elements have been converted correctly and that the appearance meets your expectations. Look out for any unintended distortions or alterations.

Manually Flattening in AutoCAD LT

If you’re using AutoCAD LT, which does not include the express tools, you can manually flatten drawings using these steps:

1. Open the Properties Palette: Access the Properties Palette for the selected objects.

2. Adjust Z-Values: Find and modify the Start Z, End Z, and Center Z values to any whole number other than zero.

3. Set Z-Values to Zero: Change each of these values back to zero. This adjustment effectively flattens the selected objects in your drawing.

4. Confirm Changes: Check your drawing to confirm that the objects are now on the same plane.

Scaling Your Flattened Drawing

Sometimes, after flattening, you may need to adjust the size of your drawing:

1. Calculate Scale Factor: Measure the intended size of your drawing and the current size. Divide the intended length by the measured length to find the scale factor.

2. Activate Scale Command: Enter the command SCALE in the command line.

3. Pick a Base Point: Choose a reference point, often the origin (0,0), to make scaling easier.

4. Input Scale Factor: Enter the calculated scale factor and press Enter. This adjusts all selected objects proportionally.

Frequently Asked Questions

1. What happens to the original 3D model after it is flattened?
The original 3D model remains unchanged; the flatten command creates a new set of 2D objects in your drawing.

2. Can I undo the flatten operation if I’m not satisfied?
Yes, you can use the Undo command to revert any changes made during the flattening process.

3. Does flattening affect the quality of my drawing?
Flattening will not typically degrade the quality of your drawing as it maintains properties like linetypes and colors. However, it is important to check the final output to ensure it meets your standards.