Tools menu: Union tool

What is the Union tool?

Union is one of the Boolean operations in Shapr3D. You can use the Union tool to merge two or more overlapping bodies into a single body, allowing you to create more complex shapes from separate geometry.

Union is useful for:

• Combining components – Merge separate bodies into a single solid.
• Creating complex shapes – Combine simpler geometric forms into a more detailed model.
• Consolidating geometry – Unite overlapping bodies before continuing with other modeling operations.

The bodies must overlap for the Union operation to succeed. You can also choose whether to keep the original bodies.

How to use the Union tool

1. Go to Tools > Union. 
   For other ways to open the tool, visit Accessing tools.
2. Select the overlapping bodies you want to combine.
3. Optional: Turn on Keep Originals to retain the separate source bodies in addition to the merged result.
4. Optional: While the tool is active, select Union again to open its parameter card and review the selected bodies or Keep Originals setting.
5. To finish, select Done or click an empty area of the modeling space.

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 parameters while using the tool or reopen them from History after completing the step.

Adjust Union parameters

While Union is active, select the tool again to display its parameter card. The current card includes:

• To Unite – Select or change the solid bodies to combine. The selected bodies must overlap.
• Keep Originals – Choose whether to retain the original separate bodies after creating the merged result. Keeping the originals can be useful if you need to reuse or modify the source bodies later. If you no longer need them as separate bodies, leave this setting off.

For more information about editing active tools, visit Parameter Cards.

Edit Union in History

1. Open History and select the Union step.
2. Review or modify the available settings, including the selected bodies and the Boolean operation type.
3. To finish editing, select Done.

Depending on the History step, the following settings may be available:

• Target – Edit the target body selection. In the original Union workflow, the last selected body is assigned as the default target.
• Tool – Edit the other bodies participating in the Boolean operation.
• Type – Change the operation to Union, Subtract, or Intersect. Review target and tool assignments after changing the type.
• Keep Target Bodies – Retain the original target bodies.
• Keep Tool Bodies – Retain the original tool bodies.

For more information, visit History.

When to use the Union tool

Use Union when overlapping solid bodies should become one continuous body. The three Boolean tools produce different results from overlapping geometry:

• Union – Combines the volumes of the selected bodies.
• Subtract – Removes the volume of one body from another.
• Intersect – Keeps the volume shared by overlapping bodies.

For a broader overview, visit Boolean operations.

Best practices and troubleshooting

Best practices

• Check that the bodies overlap before starting Union.
• Use Keep Originals when you want to preserve the individual source bodies for later use.
• Review the resulting body before continuing with downstream modeling steps.

Troubleshooting