Tutorial: Modify T-spline models

Add faces and transitions to make the T-spline primitive more like the reciprocating saw housing. Drag, scale, and weld faces to complete the shape. Finally, mirror one side of the shape to create a symmetrical model.

Create and position a T-spline face

First, add a T-spline face. Then drag the face away from the workplane to create a 3D shape.

If the Data Panel is not open, click Show Data Panel .
In the Data Panel, open 2_Creating and Modifying Conceptual Designs from Samples > Workshops & Events > Adoption Path > Conceptual Design > 2_ Create and Modify Conceptual Designs.
Choose Create > Face.
Click the XY plane to select it, and then click four points to approximate the area of the motor. This image shows the four corners after you create the face:
Choose Modify > Edit Form.
To create space for a 3D shape, drag the new face away from the workplane. Position the face 35 mm away from the origin plane.

When you finish, the face is offset 35 mm from the origin plane.

You just added a face that will become part of the reciprocating saw housing. Next, you add transition faces that fill in the housing shape.

Add transition faces to edges

Add more faces to make the T-spline more like the shape of the reciprocating saw handle.

Choose Modify > Edit Form, and select the right edge of the new face.
Alt-drag (Windows) or Option-drag (macOS) the manipulator to create a transition face that wraps around the motor housing.
Select the left edge of the face, and Alt-drag (Windows) or Option-drag (macOS) the manipulator to add a transition face around the motor. Select the new left edge again, and Alt-drag (Windows) or Option-drag (macOS) the manipulator to add another face.
To move faces to match the concept sketch, select faces and drag the manipulator. When you are done, the faces should resemble this image:
Alt-drag (Windows) or Option-drag (macOS) the manipulator to add another set of transition faces on the bottom of the geometry. When you are done, the bottom faces should resemble this image:
Manipulate the faces to closely resemble the concept sketch. When you are done, the faces should resemble this image:

Create an equal number of faces between edges

You need to create a connecting bridge between the motor housing and the handle. To do this, you'll use the Bridge command, which requires an even number of faces on both sides.

In this model, the housing has one face, and the handle has two faces. Before using the Bridge command, you must insert edges and faces to create an even number of faces.

To create two faces on the motor, subdivide a face. Begin by choosing Modify > Insert Edge.
Select the motor housing edge that is nearest the handle. Fusion calculates the location of the new edge as a fraction of the overall face size. For example, 0.5 or 50% places the edge in the middle of the existing face.
In the Insert Edge dialog, enter 0.50 mm for Insert Location. These are the faces after you subdivide them.
Drag the rightmost edge of the T-spline so that it matches the contour of the sketch. When you are done, the rear edge of the handle should look like this image:

Build a transition between bodies

In the previous topic, you created an equal number of faces between the edges of the housing and the handle. Now you can use the Bridge command to add transition faces between the two T-spline bodies.

Choose Modify > Bridge.
In the Bridge dialog, click Side 1. Then select the two edges on the bottom of the motor housing nearest the handle.
Click Side 2, and select the two edges on the bottom of the handle nearest the motor housing.
To view a preview of the faces, click Preview.

When you are done, the bridge should resemble this image:
Click OK.

Adjust bottom faces to match the concept sketch

To ensure a clean edge for the saw to sit on, you can extend faces past the edge of the concept sketch. Later, you can trim the faces in the Patch workspace. Use Edit Form to adjust the shape to resemble the concept sketch.

Choose Modify > Edit Form.
Alt-drag (Windows) or Option-drag (macOS) to add faces. When you are done, the faces should resemble this image:
Drag the faces near the handle opening to align them with the concept sketch. When you are done, the faces should resemble this image:

Add faces to the top of the saw

Next, add transition faces to create the upper part of the saw housing above the trigger. The new faces start from the top of the handle.

Choose Modify > Edit Form.
Alt-drag (Windows) or Option-drag (macOS) the manipulator to add three sets of transition faces. Drag the manipulators to scale and rotate each set of faces into position as you create them.

The faces should resemble this image:
Modify the feature line on the top edge to match the concept sketch.

When you are done, the faces on the top of the saw should resemble this image:

Use scale to flatten an edge

It is important that leading edges match easily when you combine T-spline parts. In this example, the leading edge of the faces is not straight.

You can straighten a T-spline edge by setting its angle to 0. Scaling the edge to a larger value exaggerates the angle of the edge.

Choose Modify > Edit Form.
Double-click a leading edge of the faces to select the entire edge loop. Drag the manipulator to set the angle to 0 degrees. The flattened edge should resemble this image:
Adjust the remaining faces as needed to match the T-spline shape to the concept sketch. When you are done, the top of the handle should resemble this image:

Weld vertices to create a transition

Although you added faces to the top of the housing, these faces still don't connect with the faces over the motor housing. In this step, you add faces to the motor housing to bring it closer to the top of the handle. You then weld vertices to create a transition between the motor housing and the top.

The Weld Vertices command offers three options for welding vertices:

Vertex To Vertex. Moves one vertex to another.
Vertex To Midpoint. Moves both vertices to their midpoint.
Weld Together. Welds vertices together within a tolerance.

When you weld vertices, the design temporarily appears in Box mode, which shows the topology clearly.

Note: Autodesk Fusion displays geometry in Box mode when it cannot create a smooth representation of a design.

Add faces to the top edge of the motor housing

Choose Modify > Edit Form, and then select the two faces on the upper-right corner of the motor housing.
Alt-drag (Windows) or Option-drag (macOS) the manipulator to add faces. When you are done, the faces should resemble this image:

Weld vertices to connect faces

The top of the motor housing does not connect to the handle. You must weld them together.

Choose Modify > Weld Vertices.
For Weld Mode, select Vertex To Vertex.
Select the vertex on the upper-right corner of the motor housing. Then select the vertex on the bottom facing edge of the handle.

The display switches to Box mode.
Select the vertices next to the welded vertex on the motor housing.

Once you weld the second set of vertices together, Fusion switches back to Smooth mode. After you weld these vertices, the faces should resemble this image:
To create a wider transition, select the third pair of vertices.

After you weld these vertices, the motor housing and the top should resemble this image:
Click OK.

Merge the top of the saw and the motor housing

In this step, you add three sets of faces to the top of the saw and then merge them with faces on the motor housing. You add three faces to maintain an even topology with faces on the top of the motor housing.

Choose Modify > Edit Form, and select the facing edges on the handle.
Alt-drag (Windows) or Option-drag (macOS) the manipulator to add three sets of three faces to the left of the handle. Flatten the edge of each set of faces before you create the next set.

The new faces should resemble this image:
Click OK.
Choose Modify > Merge Edge.
For Edge Group One, click Select. Then select the bottom edges on the three faces you just created.
For Edge Group Two, click Select. Then select the top edges of the three corresponding faces on the motor housing.
Click OK.

Fusion connects the edges and quickly recalculates the geometry.

Flatten vertices to a plane

Later, you'll mirror the shape to create the opposite side of the reciprocating saw. In this step, you flatten the edges that are near the origin plane. This places all edges and vertices on the origin plane, and ensures that the T-spline body can weld together properly.

The Flatten command has three options:

Fit. Flattens all vertices relative to their current position.
Select Plane. Flattens all vertices relative to a selected plane.
Select Parallel Plane. Flattens all vertices parallel to a selected plane.

To flatten the vertices:

On the original cylinder, delete any faces that cross the mirror plane. The shape should resemble this image:
Select all the parting edges down the middle of the saw. Selecting the edges before you flatten vertices automatically grabs all of the vertices on those edges. Alternatively, you can select edges individually or use a selection filter of T-spline edges and window-select.

This image shows the edges you select:
Choose Modify > Flatten.
To place the edges on the origin, for Direction, choose Select Plane.
Click the XY plane.

The edges on the inside of the T-spline shape move to the origin plane.

Mirror the shape to create a symmetrical model

You have built one side of the reciprocating saw housing. In this step, you mirror the shape to complete the housing.

The Sculpt workspace offers several ways to create mirror symmetry efficiently.

Mirror - Internal mirrors elements within a body. Mirror - Duplicate mirrors a duplicate shape on the other side of a plane. Changes to one side of the shape automatically appear on the other side.

Because the final model of the saw should be symmetrical across the plane of origin, you use Mirror - Duplicate to mirror the shape.

Choose Symmetry > Mirror - Duplicate.
Select the saw body, and then select the origin plane as the mirror plane.

Fusion creates a mirror image of the shape. The two shapes are equidistant from the origin plane. A blue edge indicates the line of symmetry.

Create and modify in the Sculpt workspace