CAD-Modeling

SolidWorks provides a robust suite of tools for surface modeling, which is crucial for designing products with complex, organic, or aesthetically driven shapes. Unlike solid modeling, which focuses on creating volumetric bodies, surface modeling emphasizes the creation and manipulation of thin-walled, non-volumetric surfaces. These surfaces can then be used for various purposes, such as defining part boundaries, creating styling features, or even converting into solid bodies.

This page outlines key concepts and frequently used commands for surface modeling in SolidWorks.

Key Surface Modeling Concepts

• Surface Body: A collection of interconnected surfaces that form a single entity. Unlike a solid body, a surface body has no thickness or internal volume.
• Knit Surface: A crucial operation that combines multiple individual surfaces into a single surface body. This is essential for creating continuous, watertight geometries.
• Trim Surface: Used to cut away portions of a surface using another surface, a sketch, a plane, or an edge as a trimming tool. This allows for precise shaping and definition of surface boundaries.
• Untrim Surface: Reverses a previous trim operation, restoring the trimmed portion of a surface.
• Extend Surface: Lengthens a surface along its edges, either by a specified distance or up to another body.
• Fillet/Chamfer Surface: Creates rounded or beveled transitions between intersecting surfaces. Note that these are distinct from solid fillets/chamfers.
• Ruled Surface: Generates a surface by sweeping a profile along a guide curve. Different types of ruled surfaces (e.g., tangent to surface, normal to surface, tapered) offer flexibility in creation.
• Loft Surface: Creates a surface by blending multiple profiles or cross-sections along guide curves. Provides powerful control over complex shapes.
• Boundary Surface: Generates a high-quality, continuous surface by blending between multiple curves in two directions (U and V). Often used for complex, freeform shapes and generally produces smoother results than loft.
• Fill Surface: Creates a surface patch to fill a closed boundary of edges, sketches, or curves. Useful for closing gaps in surface models.
• Delete Face: Removes selected faces from a solid or surface body. When used on a solid, it converts the solid into a surface body if enough faces are removed to expose an interior.
• Offset Surface: Creates a new surface at a specified distance from an existing surface.
• Thicken: Converts a surface body into a solid body by adding a specified thickness. This is a common final step in surface modeling workflows.
• Intersect: Creates new curves or surfaces at the intersection of two existing bodies (solids or surfaces).
• Split Line: Projects a sketch onto a surface, creating new edges on the surface. Useful for dividing surfaces for subsequent operations or for creating aesthetic lines.
• Freeform: A powerful tool for direct manipulation of surface curvature using control points and poles. Ideal for aesthetic refinements and ergonomic designs.
• Curvature Combs: Visual analysis tool that displays the curvature of a surface along selected edges, helping to identify imperfections or inconsistencies in the surface.
• Zebra Stripes: A visual analysis tool that projects parallel stripes onto a surface to highlight imperfections and evaluate surface continuity and smoothness.

Key Surface Modeling Commands and Features (SolidWorks Specific)

Many of the concepts above are directly implemented as features in SolidWorks. You can find these tools primarily under the Surfaces tab in the CommandManager.

• Extruded Surface: Creates a surface by extruding a sketch along a specified direction and distance.
• Revolved Surface: Creates a surface by revolving a sketch around an axis.
• Swept Surface: Creates a surface by sweeping a profile along a path.
• Knit Surface:
  • Location: Features > Surfaces > Knit Surface
  • Purpose: Combines multiple surface bodies into a single surface body. Can also be used to create a solid from a closed, watertight set of surfaces by checking "Create solid."
• Trim Surface:
  • Location: Features > Surfaces > Trim Surface
  • Purpose: Trims a portion of a surface. Offers "Standard" and "Mutual" trim options.
• Untrim Surface:
  • Location: Features > Surfaces > Untrim Surface
  • Purpose: Reverses a trim operation.
• Extend Surface:
  • Location: Features > Surfaces > Extend Surface
  • Purpose: Extends a surface along its edges.
• Fillet/Chamfer (Surface):
  • Location: Features > Surfaces > Fillet/Chamfer (Look for the surface specific icon, not the solid one)
  • Purpose: Creates rounded or beveled transitions between surfaces.
• Ruled Surface:
  • Location: Features > Surfaces > Ruled Surface
  • Purpose: Creates various types of ruled surfaces.
• Lofted Surface:
  • Location: Features > Surfaces > Lofted Surface
  • Purpose: Creates a surface by blending profiles.
• Boundary Surface:
  • Location: Features > Surfaces > Boundary Surface
  • Purpose: Creates high-quality surfaces by blending in two directions.
• Filled Surface:
  • Location: Features > Surfaces > Filled Surface
  • Purpose: Creates a surface patch to fill a boundary.
• Delete Face:
  • Location: Features > Direct Editing > Delete Face (or Search Commands)
  • Purpose: Removes faces from bodies.
• Offset Surface:
  • Location: Features > Surfaces > Offset Surface
  • Purpose: Creates an offset surface.
• Thicken:
  • Location: Features > Surfaces > Thicken
  • Purpose: Converts a surface body to a solid body.
• Intersect:
  • Location: Features > Direct Editing > Intersect (or Search Commands)
  • Purpose: Creates intersection geometry.
• Split Line:
  • Location: Features > Curves > Split Line (or Search Commands)
  • Purpose: Projects a sketch onto a surface.
• Freeform:
  • Location: Features > Surfaces > Freeform
  • Purpose: Directly manipulates surface curvature.
• Curvature Combs:
  • Location: Evaluate Tab > Curvature Combs
  • Purpose: Visual analysis of surface curvature.
• Zebra Stripes:
  • Location: Evaluate Tab > Zebra Stripes
  • Purpose: Visual analysis of surface continuity and smoothness.

Workflow Considerations

• Plan Your Design: Surface modeling often requires more upfront planning than solid modeling due to the complexity of maintaining tangency and curvature.
• Start with Basic Surfaces: Begin with simple extruded, revolved, or swept surfaces and progressively add detail.
• Maintain Tangency and Curvature: Pay close attention to the continuity between surfaces (G0, G1, G2, etc.) to ensure a smooth, aesthetically pleasing result.
• Use Analysis Tools: Regularly use Curvature Combs and Zebra Stripes to evaluate the quality of your surfaces and identify areas that need refinement.
• Knit Frequently: Knit surfaces together as you build to create a single, continuous surface body, which simplifies subsequent operations.
• Convert to Solid: Once your surface model is complete and watertight, use the "Thicken" or "Knit Surface" (with "Create solid" option) command to convert it into a solid body for manufacturing or further solid-based operations.

Tutorials

• Surface Modeling Tutorial