Creating a Sketch Mesh

Learn the basics of creating a sketch mesh by building a simple roof gutter.

Sketch meshes can render a complex shape easily. As a scene designer, you only need to describe the cross-section, and the vector or path it follows. The scene handles the complex calculations to create the final mesh.

Learn how to create a sketch mesh.

1. Prepare your scene.

First, consider the ends of the object. Usually, sketch meshes have some other meshes that define their beginning and end. For example, an electrical cable would have a plug on one end, and a socket on the other. If a plug and socket mesh both exist in your scene first, you may find it easier to create the sketch mesh that connects them. (Having objects to start or end your sketch object is not required.)

2. Create a Sketch mesh as the cross-section of the object.

3. Decide which feature best creates the length of the object: extrude or sweep.

If you were to slice through this object to create a cross-section, what would that shape be? In this step you create that cross-section. For example, if you were creating a roof gutter, the path in this step would be a U- or V-shaped cross section of the gutter itself.

4. If sweeping, then create a second sketch mesh as the path this cross-section will follow.

5. Apply the sweep or extrude feature to your cross-section sketch.

6. Adjust the cross section or path as necessary to refine the design.

1. Create a sketch mesh.
   In the node tree on the left, click Meshes > Create Sketch.

2. Add a path to the sketch mesh.
   Open the Sketch Paths expander on the right and click New Path. A path expander appears.

3. Define the path type.
   Is this a curved part of the cross-section? Or straight? Select the path type that best defines this section of the edge. Remember, you can create a sketch from multiple paths with multiple types. For example, to create the cross-section of a roof gutter, you may start your sketch with a simple “Points” path for the hard angles against the building, then add a second path of type “Bezier” to draw the curved portions visible from the street. Not sure where to start? Try using a “Points” type path to sketch out a rough cross section. You can always refine this later.

4. Add a control point to the path. Click New Control Point in the path expander you created.

5. Position the control point in the scene by setting the position X, Y, and Z properties.

6. Adjust direction properties of the control point as necessary.
   You have traced a portion of the cross-section. If this is a simple “points” path, then the direction properties are ignored. For other path types, you’ll need to adjust one or both of the direction parameters to mold the curve entering and existing this point.

7. Create the second control point.
   A path must have at least two control points. Depending on the complexity of the path, you will probably need more. Create the second control point by repeating steps 4-6. Your new control point is created at the same location as the previous point on the path. Use the move gizmo to move it to the best location: you’ll see the path appear as a line between the two control points.

8. Create remaining control points along the path.
   Our example of a roof gutter cross-section could be started by one “points” type path tracing out the hard, L-shaped angle of the gutter with 3 points.

9. If your sketch is not complete, add another path.
   Repeat steps 2 through 7 to add any more paths your sketch needs. When you create a new path, it automatically starts where the last path ended, so its easy to create one continuous line from multiple paths. Our example of a roof gutter could be completed by a second bezier type of path, starting where the “points” path ended. The points of the bezier path allow easy creation of the decorative curves of the front of the gutter, and the final curled lip at the top of the gutter.

• A simple extrude will project the sketch along a straight line. You define the simple line with a vector.

• A more complex sweep will project the sketch along any route through space you want. You specify the route with a path.

Follow the same procedure as in step 2 above to create a second mesh. This time, however, you are not creating a cross section. You are creating the path this cross-section will follow through space. For example, if you were creating a rain gutter, the path in this step would be a path along the edge of the roof.

Return to the sketch mesh you created in step 2. Add a new feature to the mesh – either Sweep or Extrude – depending on what you decided in step 3. You’ll see the final 3D object appear, which projects your cross-section path along the extruded direction (or swept path).

• Does the mesh look inside-out? Click Flip Path Direction in the sketch properties.

• Does the mesh need an end-cap? Click Add Face in the sketch properties.

If the cross-section doesn’t look right, adjust that first sketch. If the route the cross-section takes through space doesn’t look right, then adjust that second vector (if extruded) or sketch (if swept).

7. If this sketch object is dynamic, review the position mode of each point on your sweep sketch’s paths.

Your sketch may be dynamic: it may need to be longer or shorter based on Snap rules, or maybe it has connectors to other objects your user drags about the scene. For these dynamic sketch objects, you need to specify how the points in the paths move as that path changes.

• To keep a point fixed in space, set it’s position mode to absolute.

• To allow the point to move about in a flexible way to respond to changes, set the position mode to “bounding box ratio”.