Rhino 8 ShrinkWrap Guide: Turn Complex Geometry into a Mesh

This guide covers how to use the ShrinkWrap command in Rhino 8 to create a mesh from complex or problematic input, then inspect the result. The command can create a new mesh around NURBS surfaces, SubDs, meshes, point clouds and point objects. McNeel documentation presents ShrinkWrap as suitable for tasks such as creating 3D-printing meshes, solid meshes from multiple objects, and meshes from 3D scan fragments. The steps below are based on the commands and options documented for Rhino 8.

1. Check the input with Check

Before converting, select the object you want to inspect and run Check from Analyze › Diagnostics › Check. The command reports errors in the object’s data structure, helping to reveal potential issues before processing. If an error is listed, it makes more sense to review the object’s structure first rather than changing ShrinkWrap settings.

A clean result from Check does not prove that the model is flawless in every respect. Rhino documentation notes that some surface issues, such as surfaces that fold back on themselves or intersect, can be difficult to detect automatically. Treat Check as a general structural check, not as a test that certifies the geometry as a whole.

You can also use the CheckNewObjects command to monitor for invalid objects created during modeling or file import. If the command reports an issue, note which operation produced it. If you receive a warning during normal modeling, undo the operation and copy the relevant objects into a new file; include information about the command and active options in your problem report.

2. Choose ShrinkWrap settings for the task

Open the command from Mesh Tools › Mesh › Shrink Wrap. First, decide how much detail the output needs to preserve. ShrinkWrap’s Target Edge Length option sets the approximate length of mesh edges; the documentation says its default value is calculated automatically. So don’t expect one fixed default value.

Increasing Polygon Optimization can also increase deviations from the target edge length. So weigh the need for a mesh with fewer faces against the level of detail required. Offset has a more limited effect on target edge length. Rather than assuming that increasing a setting will always improve the result, use the preview to check the output.

3. Manage point data, holes and color options

Inflate Vertices and Points creates output from vertices in the input mesh or points in a point cloud. The option is on by default for point and point cloud inputs, and off for other object types. For NURBS surfaces and SubDs, it uses vertices from the objects’ render meshes. Customizing the render mesh can help if more vertices are needed. Inflated meshes merge into larger meshes only when they intersect. A negative offset pulls the output back toward the input vertices or points.

Fill holes in input objects closes holes in the input objects before creating the mesh. This can be useful in many cases, but it may also close very small gaps that were left intentionally, so consider the model’s purpose. This option has no effect with point or point cloud inputs when Inflate Vertices and Points is enabled.

If colors need to be preserved in the output, consider the Compute vertex colors option. It transfers vertex colors from meshes and display colors from point clouds to the ShrinkWrap mesh as vertex colors. Use Hide input objects if you don’t want the source objects visible in the preview; Draw mesh wires displays the mesh as a wireframe. Preview lets you see the result during the command session before creating the mesh. Delete input objects deletes the inputs if the output is created successfully, so take care with this option if you need to keep the source geometry.

4. Inspect the output and potential mesh issues

After creating the mesh, use Check again to inspect the object’s data structure. This doesn’t mean ShrinkWrap has fixed every geometry issue; if the mesh is intended for 3D printing, inspect mesh-specific defects separately. Rhino documentation notes that some STL/SLA printers may run slowly, produce unexpected results or run out of memory when working with meshes containing many long, thin faces. MeshRepair can be considered for editing these kinds of print meshes.

For specific defects, the documentation points to these tools:

• CullDegenerateMeshFaces for invalid faces and zero-length edges.

• For non-manifold edges, first use CullDegenerateMeshFaces, then ExtractNonManifoldMeshEdges.

• Use ShowEdges to find naked edges; try FillMeshHole, FillMeshHoles or MatchMeshEdge to close them.

• Use ExtractDuplicateMeshFaces for duplicate faces and UnifyMeshNormals for faces whose orientation needs correcting.

• Use SplitDisjointMesh for disconnected mesh pieces.

Rather than applying these tools indiscriminately to every output, choose the one suited to the issue found during inspection. Check’s structural assessment and mesh diagnosis and repair are not interchangeable.

Impact on architecture and visualization workflows

ShrinkWrap can be useful in workflows for architecture, interior design and visualization teams, especially when combining 3D scan fragments, creating a solid mesh from multiple inputs or trying to create a closed mesh from difficult-to-repair geometry. According to the documentation, the command is also intended for 3D printing and reverse engineering. Set the level of detail, how holes are handled and whether color transfer is needed according to the model’s intended use.

Rhino documentation does not provide specific hardware requirements, licensing terms or compatibility information for other software here. Teams should therefore check the ShrinkWrap output against the requirements of the next stage, paying particular attention to the option that deletes source objects and, for 3D printing, to mesh defects.

Common mistakes

• Raising the Polygon Optimization value without accounting for deviations from the target edge length.

• Overlooking that Fill holes in input objects may close micro-gaps that were left intentionally.

• Treating a clean Check report as proof that all surface and intersection defects have been found.

• Assuming the source geometry will be preserved when Delete input objects is enabled.

• Using the mesh for 3D printing without checking for naked edges and long, thin faces.