Component:Shelling
From DocR21
The Shelling Component (component SPAshl), creates thin-walled solids by offsetting all the faces of a solid or sheet model by a specified distance. Although shelling is a based on the Local Operations Component it handles a wide variety of topology changes. Topology changes primarily occur when offset distances force a body to self intersect or individual faces (especially blends) collapse due to their curvature.
Shelling forms an essential link between surface modeling and solid modeling. A typical application of shelling is found in sheet-metal and plastic industries where thin-walled solids need to be modeled from solids.
The Shelling Operations, Hollow Body and Sheet Thicken, are performed by copying and offsetting the faces of the input body thus creating a void. Both functional variations close the void with the creation of orthogonal rim faces, creating a closed, shelled body. A shell can be created in two ways:
| Operation | Description |
|---|---|
| Hollow Body | Creates a thin-walled solid shell from a solid body. |
| Sheet Thicken | Thickens a sheet to a solid body. |
Adaptive Offset
- Main article: Adaptive Offset
If a surface of the given body has radius of curvature smaller than the shelling thickness, then adaptive offsetting is used.
APIs
The primary C++ API for hollow body, api_hollow_body, takes a BODY, a list of open faces, an offset distance, a 3D bounding box for the intersection and options.
api_hollow_body(input body, list of open faces, distance, intersection box, options)
Additional interfaces exist that allow you to select specific offset distances for each face in the body. Refer to the Hollow Body section for additional information on behavior and interface.
The API, api_sheet_thicken, provides the ability to thicken a sheet body.
api_sheet_thicken(sheet body, thickness, logical for direction, intersection box, options)
Refer to the Sheet Thicken section for additional information on behavior and interface.
Functional Options
All Local Operations APIs accept a lop_options object. Several of these options existed as Global Options (below) in previous releases, however, they are now invoked through functional options. Refer to the Global Options documentation for complete coverage.
Global Options
The main Local Operations APIs take options to control their behavior.
Important: For historical reasons, some global options also affect the behavior of Local Operations. Refer to Local Operations global options.
