What tool would be appropriate for creating smooth curves in digital illustrations?

The Spline tool is particularly effective for creating smooth curves in digital illustrations because it allows for the manipulation of control points that dictate the shape of the curve. This tool is designed specifically to provide a high level of precision in drawing curves, making it easier to achieve the desired aesthetic in artwork and design. By adjusting the control points and tangents, users can create fluid and organic shapes that are often required in digital illustration.

Moreover, the Spline tool can automatically generate curves between points, which is beneficial for artists aiming for a smooth transition in their work. This feature enhances control over the curvature compared to other tools that may not offer the same level of fine-tuning for creating sophisticated and intricate designs.

In contrast, while the Bezier Tool also creates curves, it requires a more manual approach to adjust the handles of the Bezier points for smooth curves. The Brush Tool and Pencil Tool are more focused on painting and drawing, which may result in jagged edges or less controlled curves compared to what the Spline tool can provide.