Drake
Drake C++ Documentation
Mesh Class Referencefinal

Detailed Description

Definition of a general (possibly non-convex) mesh.

The mesh may be a triangular surface mesh or a tetrahedral volume mesh, depending on how it used.

Meshes can be used with all three roles but, currently, the support for the proximity role is limited. Where a general mesh is not supported, the mesh is replaced by its convex hull. See the documentation of QueryObject's proximity queries for more details. The notable cases where the actual mesh topology is used includes:

  • Specifying the Mesh as rigid hydroelastic.
  • Specifying the Mesh as compliant hydroelastic (when it references a tetrahedral .vtk file).
  • Specifying the Mesh as deformable (when it references a tetrahedral .vtk file).

This convex-hull substitution is a regrettable stop-gap solution until we fully support general, non-convex meshes throughout proximity queries.

For visual roles (illustration and perception), the specified mesh file is used as directly as possible.

The mesh is defined in a canonical frame C, implicit in the file parsed. Upon loading it in SceneGraph it can be scaled around the origin of C by a given scale amount.

#include <drake/geometry/shape_specification.h>

Public Member Functions

 Mesh (const std::string &filename, double scale=1.0)
 Constructs a mesh shape specification from the mesh file located at the given file path. More...
 
 ~Mesh () final
 
const std::string & filename () const
 
const std::string & extension () const
 Returns the extension of the mesh filename – all lower case and including the dot. More...
 
double scale () const
 
const PolygonSurfaceMesh< double > & convex_hull () const
 Reports the convex hull of the named mesh. More...
 
Implements CopyConstructible, CopyAssignable, MoveConstructible, MoveAssignable
 Mesh (const Mesh &)=default
 
Meshoperator= (const Mesh &)=default
 
 Mesh (Mesh &&)=default
 
Meshoperator= (Mesh &&)=default
 
- Public Member Functions inherited from Shape
virtual ~Shape ()
 
void Reify (ShapeReifier *reifier, void *user_data=nullptr) const
 Causes this description to be reified in the given reifier. More...
 
std::unique_ptr< ShapeClone () const
 Creates a unique copy of this shape. More...
 
std::string_view type_name () const
 Returns the (unqualified) type name of this Shape, e.g., "Box". More...
 
std::string to_string () const
 Returns a string representation of this shape. More...
 
template<typename ReturnType = void, typename Visitor >
decltype(auto) Visit (Visitor &&visitor) const
 Calls the given visitor function with *this as the sole argument, but with *this downcast to be the shape's concrete subclass. More...
 

Additional Inherited Members

- Protected Types inherited from Shape
using VariantShapeConstPtr = std::variant< const Box *, const Capsule *, const Convex *, const Cylinder *, const Ellipsoid *, const HalfSpace *, const Mesh *, const MeshcatCone *, const Sphere * >
 (Internal use only) All concrete subclasses, as const pointers. More...
 
- Protected Member Functions inherited from Shape
 Shape ()
 (Internal use only) Constructor for use by derived classes. More...
 
 Shape (const Shape &)=default
 (Internal use only) For derived classes. More...
 
Shapeoperator= (const Shape &)=default
 (Internal use only) For derived classes. More...
 
 Shape (Shape &&)=default
 (Internal use only) For derived classes. More...
 
Shapeoperator= (Shape &&)=default
 (Internal use only) For derived classes. More...
 

Constructor & Destructor Documentation

◆ Mesh() [1/3]

Mesh ( const Mesh )
default

◆ Mesh() [2/3]

Mesh ( Mesh &&  )
default

◆ Mesh() [3/3]

Mesh ( const std::string &  filename,
double  scale = 1.0 
)
explicit

Constructs a mesh shape specification from the mesh file located at the given file path.

Optionally uniformly scaled by the given scale factor.

The mesh file referenced can be an .obj, a volume mesh in a .vtk, or a .gltf file. However, not all file formats are appropriate for all roles. (E.g., a tetrahedral .vtk file should not be assigned a perception role.)

Parameters
filenameThe file name; if it is not absolute, it will be interpreted relative to the current working directory.
scaleAn optional scale to coordinates.
Exceptions
std::exceptionif |scale| < 1e-8. Note that a negative scale is considered valid. We want to preclude scales near zero but recognise that scale is a convenience tool for "tweaking" models. 8 orders of magnitude should be plenty without considering revisiting the model itself.

◆ ~Mesh()

~Mesh ( )
final

Member Function Documentation

◆ convex_hull()

const PolygonSurfaceMesh<double>& convex_hull ( ) const

Reports the convex hull of the named mesh.

Note: the convex hull is computed on demand on the first invocation. All subsequent invocations should have an O(1) cost.

Exceptions
ifthe referenced mesh data cannot be read or is degenerate (insufficient number of vertices, co-linear or coincident vertices, etc.) All of the vertices lying on a plane is not considered degenerate.

◆ extension()

const std::string& extension ( ) const

Returns the extension of the mesh filename – all lower case and including the dot.

In other words /foo/bar/mesh.obj and /foo/bar/mesh.OBJ would both report the ".obj" extension. The "extension" portion of the filename is defined as in std::filesystem::path::extension().

◆ filename()

const std::string& filename ( ) const

◆ operator=() [1/2]

Mesh& operator= ( Mesh &&  )
default

◆ operator=() [2/2]

Mesh& operator= ( const Mesh )
default

◆ scale()

double scale ( ) const

The documentation for this class was generated from the following file: