Modeling Complex 3D Shapes with the Solid Tools

With SketchUp’s Solid tools, you can create new shapes by combining or cutting one shape with another, making it easy to model an outer shell or joinery.

In SketchUp, a solid is any entity that has a finite closed volume. A SketchUp solid cannot have any missing faces or faces that do not meet at an edge.

Solid Tools can be found in the following locations in the SketchUp interface: 

• Tools menu

• Solid Tools toolbar

• Procedures toolbar (Union, Subtract, and Intersect only)

For more information on finding tools or toolbars, see Navigating the SketchUp Interface.

The following table introduces the available Solid tools:

Tool	Name	What It Does
	Outer Shell	Leaves only the outer faces of overlapping solids.
	Union	Combines two or more solids into a single form.
	Procedural Union	Combines two or more solids into a single form, resulting in a procedural component.
	Subtract	One solid removes part of another and is deleted.
	Procedural Subtract	One solid removes part of another and is deleted, resulting in a procedural component.
	Trim	One solid trims another but remains in the model.
	Intersect	Leaves only the intersecting geometry.
	Procedural Intersect	Leaves only the intersecting geometry, resulting in a procedural component.
	Split	Splits solids along intersecting geometry.

Outer Shell

The Outer Shell tool ( ) removes geometry inside overlapping groups or components, leaving only the outer faces.

To create an outer shell from pre-selected overlapping groups or components, context-click your selection and choose Outer Shell from the menu.

To create an outer shell without selecting geometry first, follow these steps:

1. Activate the Outer Shell tool ().

2. Select the first group or component in your outer shell.

3. Select a second group or component. SketchUp combines your selections into an outer shell so that only the outer faces remain.

4. (Optional) Continue selecting additional groups or components to add them to your outer shell. The resulting outer shell becomes a group.

Tip: The outer shell only affects external faces. If you need to merge both external and internal geometry, use the Union tool ().

Union

The Union tool () merges two or more solid entities into a single solid. To create a union from pre-selected geometry, context-click your selection and choose Solid Tools > Union from the menu.

To use the Union tool to combine solid entities, follow these steps:

1. Activate the Union tool ().

2. Select the first group or component for the union.

3. Select the second group or component. The resulting union of the geometry remains.

4. (Optional) Continue selecting additional groups or components to add them to the union. The resulting union becomes a group.

   

Procedural Union

Procedural Union (icon) follows the same workflow. When the operation is complete, the union becomes a procedural component instead of a group.

Each time you add another solid to your union, it nests the first union component within the now larger union component. You can then modify each part of the union independently.

Subtract

With the Subtract tool (), you can use one solid entity to cut another solid entity. SketchUp then subtracts your original solid entity from the model. For the subtraction to work, the two solids need to overlap.

To perform subtraction using pre-selected entities, context-click the selection and choose Solid Tools > Subtract from the menu. SketchUp uses the order in which you selected each solid entity to determine which is the cutting entity, and which is cut. To subtract using the Subtract tool, follow these steps:

1. Select the Subtract tool ().

2. Select the cutting group or component.

   

3. Click the group or component you want to cut. The cutting group disappears but makes a hole in the second selection.

   

Procedural Subtract

Procedural Subtract (icon) creates a non-destructive procedural component that preserves the solid you used to perform the operation.

You can then edit the two solids for a different result just like you would any other component. Additional options in the Controls section of the Entity Info panel let you reverse the subtraction order or choose not to preserve the original solids.

Trim

With the Trim tool (), you cut one solid entity with another just like subtraction. However, when you use the Trim tool, the cutting solid remains in the model. If you use a peg to trim a board, the peg remains after it cuts the board. Like all the Solid tools, the Trim tool works only if two solid entities overlap.

To perform a trim, follow these steps:

1. Select the Trim tool ().

2. Select the cutting group or component. 

3. Select the group or component you want to cut. The cutting group remains but makes a hole in the second selection.

Intersect

With the Intersect tool (), selecting two or more overlapping solids removes everything but  the intersecting geometry.

To intersect pre-selected solids, context-click your selection and choose Solid Tools > Intersect from the menu. To use the Intersect tool, follow these steps:

1. Select the Intersect tool ().

2. Select a solid entity that you want to use in the intersection.

3. Select one or more additional solids that overlap your initial selection. The resulting intersecting geometry remains.

Procedural Intersect

Procedural Intersect () creates a non-destructive procedural component that preserves the solid you used to perform the operation.

You can then edit the two solids for a different result just like you would any other component.

Split

With the Split tool ( ), you can divide overlapping solid entities along their intersecting edges. To perform a split, follow these steps:

1. Select the Split tool ( ).

2. Select the first solid.

3. Select another solid that intersects your first selection. SketchUp splits all the geometry along the edges where the selected solids intersect.