ADD remesh_dual

Author: pv

CHANGELOG.md

@@ -18,6 +18,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+* Added `compas_cgal.meshing.mesh_remesh_dual`.
+
 ### Changed
 
 ### Removed

docs/examples/example_meshing.py

@@ -10,14 +10,17 @@
 from compas.geometry import transform_points_numpy
 from compas_viewer import Viewer
 
-from compas_cgal.meshing import mesh_remesh
-
+from compas_cgal.meshing import mesh_remesh, mesh_remesh_dual
+from compas_cgal import _types_std  # noqa: F401
 
 def main():
     """Remesh a bunny mesh that is loaded from .ply file."""
 
     FILE = Path(__file__).parent.parent.parent / "data" / "Bunny.ply"
+    
     bunny = Mesh.from_ply(FILE)
+    #bunny = Mesh.from_meshgrid(1,10,1,10)
+    bunny.quads_to_triangles()
     bunny.remove_unused_vertices()
 
     centroid = bunny.vertex_point(0)
@@ -32,14 +35,22 @@ def main():
     V0, F0 = bunny.to_vertices_and_faces()
     V1 = transform_points_numpy(V0, R * S * T)
 
-    V1, F1 = mesh_remesh((V0, F0), 0.3, 10)
-    V1 = transform_points_numpy(V1, Translation.from_vector([20, 0, 0]))
+
+    edge_length = 0.005
+    iterations = 10
+    V1, F1 = mesh_remesh((V0, F0), edge_length, iterations)
+    V1 = transform_points_numpy(V1, Translation.from_vector([0.15, 0, 0]))
     mesh = Mesh.from_vertices_and_faces(V1, F1)
+    
+
+    V1, F1 = mesh_remesh_dual((V0, F0), edge_length, iterations, 3.14, True)
+    V1 = transform_points_numpy(V1, Translation.from_vector([0.3, 0, 0]))
+    dual = Mesh.from_vertices_and_faces(V1, F1)
 
-    return bunny, mesh
+    return bunny, mesh, dual
 
 
-bunny, mesh = main()
+bunny, mesh, dual = main()
 
 
 # ==============================================================================
@@ -49,9 +60,10 @@ def main():
 viewer = Viewer(width=1600, height=900)
 
 viewer.renderer.camera.target = [0, 0, 0]
-viewer.renderer.camera.position = [0, -25, 10]
+viewer.renderer.camera.position = [0, -0.25, 0.10]
 
 viewer.scene.add(bunny, show_points=False)
 viewer.scene.add(mesh, show_points=False)
+viewer.scene.add(dual, show_points=True)
 
 viewer.show()

src/compas_cgal/meshing.py

@@ -52,3 +52,63 @@ def mesh_remesh(
     V = np.asarray(V, dtype=np.float64, order="C")
     F = np.asarray(F, dtype=np.int32, order="C")
     return _meshing.remesh(V, F, target_edge_length, number_of_iterations)
+
+
+def mesh_remesh_dual(
+    mesh: VerticesFaces,
+    target_edge_length: float,
+    number_of_iterations: int = 10,
+    angle_radians: float = 0.0,
+    circumcenter: bool = True,
+) -> tuple[np.ndarray, list[list[int]]]:
+    """Create a dual mesh from a triangular mesh with variable-length faces.
+
+    Parameters
+    ----------
+    mesh : :attr:`compas_cgal.types.VerticesFaces`
+        The mesh to create a dual from.
+    target_edge_length : float
+        The target edge length for primal mesh remeshing before dual creation.
+    number_of_iterations : int, optional
+        Number of remeshing iterations for the primal mesh.
+    angle_radians : double, optional
+        Angle limit in radians for boundary vertices to remove.
+    circumcenter : bool, optional
+        Whether to use the circumcenter of the triangle instead of the centroid.
+
+    Returns
+    -------
+    tuple
+        A tuple containing:
+        - Dual mesh vertices as an Nx3 numpy array.
+        - Variable-length faces as a list of lists of vertex indices.
+
+    Notes
+    -----
+    This dual mesh implementation includes proper boundary handling by:
+    1. Creating vertices at face centroids of the primal mesh
+    2. Creating additional vertices at boundary edge midpoints
+    3. Creating proper connections for boundary edges
+
+    Examples
+    --------
+    >>> from compas.datastructures import Mesh
+    >>> from compas_cgal.meshing import mesh_remesh_dual
+
+    >>> # Create a simple quad mesh
+    >>> mesh = Mesh.from_vertices_and_faces([[0, 0, 0], [1, 0, 0], [1, 1, 0], [0, 1, 0]], [[0, 1, 2, 3]])
+    >>> vertices, faces = mesh.to_vertices_and_faces()
+
+    >>> # Create its dual mesh with variable-length faces
+    >>> V, F = mesh_remesh_dual((vertices, faces), 0.1)
+    >>> dual_mesh = Mesh.from_vertices_and_faces(V, [])
+    >>> # Add the variable-length faces to the mesh
+    >>> for face in F:
+    ...     dual_mesh.add_face(face)
+
+    """
+    V, F = mesh
+    V = np.asarray(V, dtype=np.float64, order="C")
+    F = np.asarray(F, dtype=np.int32, order="C")
+    vertices, var_faces = _meshing.remesh_dual(V, F, target_edge_length, number_of_iterations, angle_radians, circumcenter)
+    return vertices, var_faces