add CGAL heat geodesics method option

- add get_cgal_HEAT_geodesic_distances using compas_cgal.HeatGeodesicSolver
- add HEAT_CGAL enum to GeodesicsMethod
- CGAL heat ~2.1s vs libigl ~3.1s in full workflow (30% faster)

Author: jf---

src/compas_slicer/config.py

@@ -30,6 +30,7 @@ class GeodesicsMethod(str, Enum):
 
     EXACT_IGL = "exact_igl"
     HEAT_IGL = "heat_igl"
+    HEAT_CGAL = "heat_cgal"
     HEAT = "heat"
 
 

src/compas_slicer/pre_processing/preprocessing_utils/compound_target.py

@@ -13,14 +13,15 @@
 
 import compas_slicer.utilities as utils
 from compas_slicer.pre_processing.preprocessing_utils.geodesics import (
+    get_cgal_HEAT_geodesic_distances,
     get_custom_HEAT_geodesic_distances,
     get_igl_EXACT_geodesic_distances,
     get_igl_HEAT_geodesic_distances,
 )
 
 logger = logging.getLogger('logger')
 
-GeodesicsMethod = Literal['exact_igl', 'heat_igl', 'heat']
+GeodesicsMethod = Literal['exact_igl', 'heat_igl', 'heat_cgal', 'heat']
 UnionMethod = Literal['min', 'smooth', 'chamfer', 'stairs']
 
 
@@ -151,6 +152,9 @@ def compute_geodesic_distances(self) -> None:
         elif self.geodesics_method == 'heat_igl':
             distances_lists = [get_igl_HEAT_geodesic_distances(self.mesh, vstarts) for vstarts in
                                self.clustered_vkeys]
+        elif self.geodesics_method == 'heat_cgal':
+            distances_lists = [get_cgal_HEAT_geodesic_distances(self.mesh, vstarts) for vstarts in
+                               self.clustered_vkeys]
         elif self.geodesics_method == 'heat':
             distances_lists = [get_custom_HEAT_geodesic_distances(self.mesh, vstarts, str(self.OUTPUT_PATH)) for vstarts in
                                self.clustered_vkeys]

src/compas_slicer/pre_processing/preprocessing_utils/geodesics.py

@@ -22,6 +22,7 @@
 
 __all__ = ['get_igl_EXACT_geodesic_distances',
            'get_igl_HEAT_geodesic_distances',
+           'get_cgal_HEAT_geodesic_distances',
            'get_custom_HEAT_geodesic_distances',
            'GeodesicsCache']
 
@@ -120,6 +121,50 @@ def get_igl_HEAT_geodesic_distances(
     return _geodesics_cache.get_distances(mesh, vertices_start, method='heat')
 
 
+# CGAL heat method solver cache (for precomputation reuse)
+_cgal_solver_cache: dict[int, object] = {}
+
+
+def get_cgal_HEAT_geodesic_distances(
+    mesh: Mesh, vertices_start: list[int]
+) -> NDArray[np.floating]:
+    """
+    Calculate geodesic distances using CGAL heat method.
+
+    Uses compas_cgal's HeatGeodesicSolver which provides CGAL's Heat_method_3
+    implementation with intrinsic Delaunay triangulation.
+
+    Parameters
+    ----------
+    mesh : Mesh
+        A compas mesh (must be triangulated).
+    vertices_start : list[int]
+        Source vertex indices.
+
+    Returns
+    -------
+    NDArray
+        Minimum distance from any source to each vertex.
+    """
+    from compas_cgal.geodesics import HeatGeodesicSolver
+
+    # Check if we have a cached solver for this mesh
+    mesh_hash = hash((len(list(mesh.vertices())), len(list(mesh.faces()))))
+    if mesh_hash not in _cgal_solver_cache:
+        _cgal_solver_cache.clear()  # Clear old solvers
+        _cgal_solver_cache[mesh_hash] = HeatGeodesicSolver(mesh)
+
+    solver = _cgal_solver_cache[mesh_hash]
+
+    # Compute distances for each source and take minimum
+    all_distances = []
+    for source in vertices_start:
+        distances = solver.solve([source])
+        all_distances.append(distances)
+
+    return np.min(np.array(all_distances), axis=0)
+
+
 def get_custom_HEAT_geodesic_distances(
     mesh: Mesh,
     vi_sources: list[int],