Mesh Generation and ShrinkWrap in Rhino 8: Clean Models with the Right Settings

Rhino 8’s official documentation describes the Mesh and ShrinkWrap commands as offering options for converting model geometry into polygon meshes suited to different purposes. The Mesh command works with NURBS surfaces, polysurfaces and SubD objects, while ShrinkWrap can also generate a new mesh around meshes, point clouds and point objects. The settings you choose depend on your goal, such as displaying a model, exporting it, or creating closed geometry from scan data.

1. Choose your starting settings with the Mesh command

Rhino’s Mesh command creates a separate, editable polygon mesh from the source object. According to the documentation, a mesh generated from a solid is continuous and closed, which can be useful when exporting to rapid-prototyping file formats such as STL. Render meshes used for viewport shading, however, are not editable in the same way; the documentation says they can be extracted with the ExtractRenderMesh command.

At the outset, the density slider in the simple mesh controls affects how closely the mesh edges follow the surface. The default density is 0.5, and the accepted range is 0 to 1. As the value increases, so does the polygon count. Higher density may therefore be appropriate when a closer representation of the surface is needed, but setting it to the maximum is not necessary for every model.

For an initial test, turn on the preview and inspect the mesh wires. Consider whether the level of detail is sufficient, the surface shape is preserved, and the model’s intended downstream use. Rhino’s documentation also explains how to preview mesh settings and restore the defaults.

2. Balance detail and performance

Each setting in the detailed mesh options has a different effect. The values below are the defaults and recommended ranges specified in the Rhino 8 documentation. For more controlled tests, focus on the setting that affects the result rather than changing them all at once.

When Refine mesh is enabled, Rhino subdivides some quads until they meet the specified criteria. Disabling this can speed up mesh generation, but may reduce accuracy and polygon count. Criteria such as Maximum angle, edge length and distance from the surface can be used to control where more detail is needed. Maximum edge length can help produce polygons of roughly similar size.

If gaps between parts of a polysurface need to be avoided, pay attention to the Jagged seams option. When enabled, surfaces are meshed separately and their edges are not joined. This can make processing faster and reduce the polygon count, but may leave cracks at the seams. The documentation states that with the option disabled, a closed mesh is produced.

3. Wrap complex inputs with ShrinkWrap

ShrinkWrap generates a mesh around the selected geometry. The official documentation gives examples including meshes for 3D printing, creating a solid mesh from multiple objects, combining 3D scan fragments, meshing point clouds, and converting difficult-to-repair geometry into a closed mesh.

1. Select the inputs and inspect the preview. ShrinkWrap supports NURBS surfaces, SubD objects, meshes, point clouds and point objects. The preview lets you see the output mesh during the command. Options to show mesh wires and hide the inputs during preview are available when needed.

2. Set Target Edge Length according to your goal. This setting determines the approximate length of the edges in the output mesh. The default is calculated automatically. Since the source documentation does not specify a target value, test and preview the result based on the model’s size.

3. Check the Offset direction. A positive value expands the mesh outwards and increases the number of faces. A negative value shrinks the mesh and reduces the number of faces. Offset has a more limited effect on the target edge length.

4. Use Smoothing iterations and Polygon Optimization with care. Setting Smoothing to 0 disables smoothing. Higher values reduce the number of faces further and pull the mesh farther inward. Polygon Optimization ranges from 0% to 100%; increasing it reduces more faces, while faces on sharp edges are preserved.

5. Evaluate point data and holes separately. Inflate Vertices and Points creates the output mesh from every vertex or point in a mesh or point cloud. It is on by default for point clouds and points, and off for other object types. Fill holes in input objects can be useful in many cases, but check the result because it may also close small gaps intentionally left in the design.

4. Considerations for architecture and visualization workflows

Architects and interior designers can use the Mesh command to prepare surface models for export or other polygon-based applications. For archviz teams, mesh density is a key trade-off between detail and polygon count. Higher density creates more faces, while the “Jagged and faster” quality preset in the documentation is described as shading NURBS objects faster at lower density, with some loss of quality.

Those working with scan data or geometry that is difficult to repair can benefit from ShrinkWrap’s options for creating closed meshes and processing point-cloud inputs. Still, the result depends on the Offset, smoothing, hole-filling and point/vertex inflation settings, so check the final mesh against the project’s requirements. The documentation does not provide information about licensing, hardware requirements or compatibility with specific export formats, so no assumptions should be made on these points.

Common mistakes

• Treating increased density as a universally better solution: it also increases the polygon count.

• Leaving Jagged seams enabled while expecting the mesh edges of joined surfaces to be stitched: this option can result in cracks.

• Confusing the effects of positive and negative Offset in ShrinkWrap: one expands the mesh, the other shrinks it.

• Using Fill holes in input objects without checking for small gaps that are part of the design.

• Relying on the option to delete source objects without first checking the ShrinkWrap preview.