How to Use Subtract AutoCAD

Understanding the Subtract Function in AutoCAD

Mastering how to subtract shapes and volumes in AutoCAD can significantly enhance your design capabilities. This function allows you to create complex forms by removing overlapping parts from solid objects, surfaces, and regions. Here is a detailed guide on how to effectively use the subtract function in AutoCAD.

Using the SUBTRACT Command

The most common method to perform subtraction in AutoCAD is through the SUBTRACT command. Follow these steps:

1. Initiate the Command: Start by typing SUBTRACT in the command line and hit ENTER.
2. Select the Base Object: Click on the solid, surface, or region that you want to subtract from. After selecting, press ENTER.
3. Select the Object to Subtract: Now, click on the solid, surface, or region that you wish to remove from the base object. Once selected, press ENTER again.
4. Review the Result: Check the modified object to ensure the subtraction has processed correctly.

Shortcut Keys for Subtracting

To speed up your workflow, you can use shortcut keys to access the subtract functionality quickly.

• Windows: Press Ctrl + Alt + S.
• Mac: Use Cmd + Option + S.

These shortcuts can save time when you frequently need to perform subtractions.

Subtracting Spaces

Subtracting spaces in AutoCAD can be intuitive if you follow these steps:

1. Select the Larger Space: Click on the space you wish to keep.
2. Access the AEC Modify Tools: Right-click on your selection, navigate to the AEC Modify Tools, then select Subtract.
3. Choose the Smaller Space: Click on the smaller space that you want to remove from the larger one.
4. Finalize the Operation: Confirm your selection, and AutoCAD will perform the subtraction.

Deselecting Objects

If you’ve made a selection and need to change it, utilize the deselection commands. You can use:

• Deselection Icon: Click the icon designated for deselection on the toolbar.
• Keyboard Shortcuts:
  • ALT + SHIFT + C or ALT + C
  • CTRL + SHIFT + Z

These commands will help you manage your selections effectively.

Working with the Presspull Command

The Presspull command can create 3D shapes from 2D outlines. Here’s how to use it:

1. Invoke the Command: Type PRESSPULL in the command line and press ENTER.
2. Select a Closed Boundary: Click on an enclosed area you want to extrude or pull.
3. Define the Direction and Distance: Drag your cursor to pull the area to the desired thickness and click to finish.

Adding and Subtracting Areas

To add or subtract areas within AutoCAD:

1. Start the AREA Command: Type AREA in the command line and press ENTER.
2. Choose to Add or Subtract: Select Add area to total, or Subtract to find the difference between spaces.
3. Select Objects: Click on each object accordingly, and AutoCAD will present you with the summed up area or remaining area post-subtraction.

FAQ

What should I do if I can’t find the SUBTRACT command?
Check if you are in the correct workspace where the Subtract function is available. You can also type HELP for guidance.

Can I undo a subtraction action?
Yes, use the UNDO command or press Ctrl + Z to revert your last action.

What if I want to subtract a hatch area?
To subtract a hatch area, double-click the hatch, open the Hatch Editor, and choose the "Pick Points" option. Type ‘S’ in the command line and select the area you wish to remove.

By understanding these concepts and tools, you can effectively use the subtraction function in AutoCAD to enhance your design projects.