Tools menu: Subtract tool

What is the Subtract tool?

Subtract is one of the Boolean operations in Shapr3D. You can use the Subtract tool to remove the overlapping volume of one or more bodies from another body, creating cutouts, openings, and more complex shapes.

Subtract is useful for:

• Creating cutouts – Remove material to form holes, recesses, and pockets.
• Shaping parts – Use another solid body to define a curved or irregular removal area.
• Refining models – Remove overlapping material from existing geometry.

Note: You need at least two overlapping solid bodies to perform a subtraction.

How to use the Subtract tool

1. Go to Tools > Subtract. 
   For other ways to open the tool, visit Accessing tools.
2. Select the body or bodies you want to subtract from. These are the bodies that will be modified. They are highlighted in purple and marked with a + badge.
3. Select the overlapping body or bodies to subtract. These define the volume to remove and are highlighted in blue with a − badge. Select a badge if you need to change a body's role in the operation.
4. Optional: Adjust Keep Modified Bodies and Keep Subtracted Bodies to retain either or both sets of original bodies.
5. To finish, select Done.

You can also review the selected bodies and retention settings in the Subtract parameter card while the tool is active.

Parameter Card and History Settings

Shapr3D records the tools you use as steps in History, allowing you to revisit and modify them later. Each History step stores its parameters, which you can access through the parameter card. You can adjust these parameters while using the tool or reopen the parameter card from History after completing the step.

Adjust Subtract parameters

While Subtract is active, open its parameter card to review or change the following settings:

• Subtract From – Select the bodies to remove material from (called Target bodies in some CAD workflows).
• To Subtract – Select the bodies whose overlapping volume will be removed (called Tool bodies in some CAD workflows).
• Keep Modified Bodies – Keep the original bodies selected under Subtract From. Keeping the originals can be useful if you need to reuse or modify them later. If you only need the resulting bodies, leave this setting off.
• Keep Subtracted Bodies – Keep the original bodies selected under To Subtract. Keeping these bodies can be useful if you need to reuse them for other operations. If you no longer need them, leave this setting off.

Edit Subtract in History

1. Open History and select the Subtract step. For more about editing steps, visit History.
2. Review or update the selected bodies, the Type of Boolean operation, and the settings for retaining original bodies.
3. To finish editing, select Done.

Depending on the History interface, you may encounter these parameter names:

• Target – The body or bodies to subtract from (Subtract From).
• Tool – The body or bodies used to remove material (To Subtract).
• Type – Change the Boolean operation to Union, Subtract, or Intersect. Review the body selections after changing the operation.
• Keep Target Bodies – Retain the original modified bodies.
• Keep Tool Bodies – Retain the original subtracted bodies.

When to use the Subtract tool

Use Subtract when one body defines material that needs to be removed from another. Other Boolean operations produce different results:

• Subtract removes the overlapping volume from the bodies being modified.
• Union combines overlapping bodies into a single body.
• Intersect retains the overlapping volume shared by selected bodies.

For a broader explanation of how these operations compare, visit Boolean operations.

Best practices and troubleshooting

• Check for overlap. The bodies must share volume for Subtract to remove material.
• Check the selection roles. Select the bodies you want to modify under Subtract From and the cutting bodies under To Subtract.
• Keep originals when needed. Enable the appropriate retention setting if you plan to reuse a source body.