Improved render previews

src/fluency/geometry_occ/kernel.py

@@ -54,6 +54,7 @@ class OCGeometryKernel(GeometryKernel):
     def create_point(self, x: float, y: float) -> GeometryObject:
         """Create a 2D point."""
         from OCP.gp import gp_Pnt
+
         return OCCGeometryObject(gp_Pnt(x, y, 0))
 
     def create_line(self, start: Point2D, end: Point2D) -> GeometryObject:
@@ -61,9 +62,7 @@ class OCGeometryKernel(GeometryKernel):
         from OCP.gp import gp_Pnt
         from OCP.BRepBuilderAPI import BRepBuilderAPI_MakeEdge
 
-        edge = BRepBuilderAPI_MakeEdge(
-            gp_Pnt(start.x, start.y, 0), gp_Pnt(end.x, end.y, 0)
-        ).Edge()
+        edge = BRepBuilderAPI_MakeEdge(gp_Pnt(start.x, start.y, 0), gp_Pnt(end.x, end.y, 0)).Edge()
         return OCCGeometryObject(edge, {"type": "line"})
 
     def create_circle(self, center: Point2D, radius: float) -> GeometryObject:
@@ -71,9 +70,7 @@ class OCGeometryKernel(GeometryKernel):
         from OCP.gp import gp_Pnt, gp_Dir, gp_Ax2, gp_Circ
         from OCP.BRepBuilderAPI import BRepBuilderAPI_MakeEdge
 
-        circ = gp_Circ(
-            gp_Ax2(gp_Pnt(center.x, center.y, 0), gp_Dir(0, 0, 1)), radius
-        )
+        circ = gp_Circ(gp_Ax2(gp_Pnt(center.x, center.y, 0), gp_Dir(0, 0, 1)), radius)
         edge = BRepBuilderAPI_MakeEdge(circ).Edge()
         return OCCGeometryObject(edge, {"type": "circle"})
 
@@ -88,9 +85,7 @@ class OCGeometryKernel(GeometryKernel):
         start_rad = math.radians(start_angle)
         end_rad = math.radians(end_angle)
 
-        circ = gp_Circ(
-            gp_Ax2(gp_Pnt(center.x, center.y, 0), gp_Dir(0, 0, 1)), radius
-        )
+        circ = gp_Circ(gp_Ax2(gp_Pnt(center.x, center.y, 0), gp_Dir(0, 0, 1)), radius)
         edge = BRepBuilderAPI_MakeEdge(circ, start_rad, end_rad).Edge()
         return OCCGeometryObject(edge, {"type": "arc"})
 
@@ -159,8 +154,7 @@ class OCGeometryKernel(GeometryKernel):
             face = self._get_shape(sketch)
         if face is None:
             raise ValueError(
-                "Cannot extrude: sketch has no geometry. "
-                "Draw a closed profile before extruding."
+                "Cannot extrude: sketch has no geometry. Draw a closed profile before extruding."
             )
         # If the wrapper class itself leaked through somehow, surface a
         # clear error instead of letting BRepPrimAPI_MakePrism raise an
@@ -204,6 +198,7 @@ class OCGeometryKernel(GeometryKernel):
     def _sketch_normal(obj: GeometryObject) -> Tuple[float, float, float]:
         """Return the normal stored on a sketch-derived geometry object, else +Z."""
         import numpy as np
+
         meta = getattr(obj, "metadata", None) or {}
         n = meta.get("normal")
         if n is None:
@@ -453,7 +448,6 @@ class OCGeometryKernel(GeometryKernel):
         origin: Tuple[float, float, float] = (0, 0, 0),
     ) -> GeometryObject:
         """Rotate a body around an axis."""
-        import math
         shape = self._get_shape(body)
         from OCP.BRepBuilderAPI import BRepBuilderAPI_Transform
         from OCP.gp import gp_Trsf, gp_Ax1, gp_Pnt, gp_Dir
@@ -562,6 +556,52 @@ class OCGeometryKernel(GeometryKernel):
         shape = reader.OneShape()
         return OCCGeometryObject(shape, {"type": "imported_step"})
 
+    def import_step_components(self, filepath: str) -> list:
+        """Import a STEP file and return each solid as a separate ``(name, shape)`` pair.
+
+        The STEP reader transfers the entire root shape, then we iterate
+        over individual ``TopAbs_SOLID`` entities so that each solid gets
+        its own ``OCCGeometryObject``.  If the file contains only a single
+        solid the list will have one entry.
+
+        Returns a list of ``(name, OCCGeometryObject)`` tuples.
+        """
+        from OCP.STEPControl import STEPControl_Reader
+        from OCP.IFSelect import IFSelect_RetDone
+        from OCP.TopExp import TopExp_Explorer
+        from OCP.TopAbs import TopAbs_SOLID
+        from OCP.TopoDS import TopoDS
+
+        reader = STEPControl_Reader()
+        status = reader.ReadFile(filepath)
+
+        if status != IFSelect_RetDone:
+            raise ValueError(f"Failed to read STEP file: {filepath}")
+
+        reader.TransferRoots()
+        shape = reader.OneShape()
+
+        # Extract individual solids
+        solids: list = []
+        explorer = TopExp_Explorer(shape, TopAbs_SOLID)
+        idx = 0
+        while explorer.More():
+            solid = TopoDS.Solid_s(explorer.Current())
+            idx += 1
+            solids.append(
+                (
+                    f"Part {idx}",
+                    OCCGeometryObject(solid, {"type": "imported_step"}),
+                )
+            )
+            explorer.Next()
+
+        # Fallback: no individual solids found — return the whole shape
+        if not solids:
+            solids = [("Imported", OCCGeometryObject(shape, {"type": "imported_step"}))]
+
+        return solids
+
     def import_iges(self, filepath: str) -> GeometryObject:
         """Import from IGES format."""
         from OCP.IGESControl import IGESControl_Reader
@@ -643,10 +683,8 @@ class OCGeometryKernel(GeometryKernel):
 
         from OCP.TopExp import TopExp_Explorer
         from OCP.TopAbs import TopAbs_EDGE
-        from OCP.BRep import BRep_Tool
-        from OCP.TopLoc import TopLoc_Location
         from OCP.BRepAdaptor import BRepAdaptor_Curve
-        from OCP.GeomAbs import GeomAbs_Line, GeomAbs_Circle, GeomAbs_Ellipse, GeomAbs_BSplineCurve
+        from OCP.GeomAbs import GeomAbs_Line
 
         vertices_list: List[List[float]] = []
         edges_list: List[List[int]] = []
@@ -678,6 +716,7 @@ class OCGeometryKernel(GeometryKernel):
         explorer = TopExp_Explorer(shape, TopAbs_EDGE)
         while explorer.More():
             from OCP.TopoDS import TopoDS
+
             edge = TopoDS.Edge_s(explorer.Current())
             edge_points = discretize_edge(edge)