fixes #1208

the updated scipy dependency is due to the Slerp being added in 1.2

see: https://docs.scipy.org/doc/scipy/reference/generated/scipy.spatial.transform.Slerp.html

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+* Added an `compas.geometry.Frame.interpolate_frame(s)` method
+
 ### Changed
 
 * Changed and updated the `compas_view2` examples into `compas_viewer`.

requirements.txt

@@ -2,6 +2,6 @@
 jsonschema
 networkx >= 3.0
 numpy >= 1.15.4
-scipy >= 1.1
+scipy >= 1.2
 typing_extensions
 watchdog; sys_platform != 'emscripten'

src/compas/geometry/frame.py

@@ -24,6 +24,14 @@
 from .point import Point
 from .quaternion import Quaternion
 
+from scipy.spatial.transform import Rotation as R
+from scipy.spatial.transform import Slerp
+from ..itertools import linspace
+
+
+# from compas.geometry import Frame, Point, Vector
+# from typing import List
+
 
 class Frame(Geometry):
     """A frame is defined by a base point and two orthonormal base vectors.
@@ -588,6 +596,86 @@ def to_transformation(self):
         """
         return Transformation.from_frame(self)
 
+
+    # def frame_to_rotation_matrix(frame: Frame) -> np.ndarray:
+    #     """Convert a COMPAS frame to a rotation matrix."""
+    #     return np.array(frame.rotation_matrix)
+    #
+    # def rotation_matrix_to_quat(matrix: np.ndarray) -> np.quaternion:
+    #     """Convert a rotation matrix to a quaternion."""
+    #     return R.from_matrix(matrix).as_quat()
+    #
+    # def quat_to_rotation_matrix(quat: np.quaternion) -> np.ndarray:
+    #     """Convert a quaternion to a rotation matrix."""
+    #     return R.from_quat(quat).as_matrix()
+
+    def interpolate_frame(self, other, t):
+        """Interpolates between two frames at a given parameter t in the range [0, 1]
+
+        Parameters
+        ----------
+        other : :class:`compas.geometry.Frame`
+        t: float
+            a parameter in the range [0-1]
+
+        Returns
+        -------
+        :class:`compas.geometry.Frame`
+            the interpolated frame
+
+        Examples
+        --------
+        >>> frame1 = Frame(Point(0, 0, 0), Vector(1, 0, 0), Vector(0, 1, 0))
+        >>> frame2 = Frame(Point(1, 1, 1), Vector(0, 0, 1), Vector(0, 1, 0))
+        >>> start_frame = frame1.interpolate_frame(frame2, 0)
+        >>>> allclose(start_frame.point, frame1.point) and allclose(start_frame.quaternion, frame1.quaternion)
+        True
+        """
+        quat1 = Quaternion.from_frame(self)
+        quat2 = Quaternion.from_frame(other)
+        key_rotations = R.from_quat([quat1, quat2])
+
+        key_times = [0.0, 1.0]
+
+        slerp = Slerp(key_times, key_rotations)
+
+        interpolated_rot = slerp([t])[0]
+
+        # Interpolate origin
+        origin_interpolated = (self.point * (1.0 - t)) + other.point * t
+
+        # Convert interpolated quaternion back to a compas Quaternion
+        rot = Quaternion(*interpolated_rot.as_quat().tolist())
+
+        # Create a new frame with the interpolated position and orientation
+        interpolated_frame = Frame.from_quaternion(rot, origin_interpolated)
+
+        return interpolated_frame
+
+    def interpolate_frames(self, other, steps):
+        """Generates a specified number of interpolated frames between two given frames
+
+        Parameters
+        ----------
+        other: Frame
+        steps: int
+            the number of interpolated frames to return
+
+        Returns
+        -------
+        list of :class:`compas.geometry.Frame`
+
+        Examples
+        --------
+        >>> frame1 = Frame(Point(0, 0, 0), Vector(1, 0, 0), Vector(0, 1, 0))
+        >>> frame2 = Frame(Point(1, 1, 1), Vector(0, 0, 1), Vector(0, 1, 0))
+        >>> steps = 5
+        >>> frames = frame1.interpolate_frames(frame2, steps)
+        >>> assert len(frames) == steps
+        True
+        """
+        return [self.interpolate_frame(other, t) for t in linspace(0, 1, steps)]
+
     # ==========================================================================
     # Methods
     # ==========================================================================

tests/compas/geometry/test_frame.py

@@ -68,3 +68,16 @@ def test_frame_predefined():
     assert frame.point == Point(0, 0, 0)
     assert frame.xaxis == Vector(0, 0, 1)
     assert frame.yaxis == Vector(1, 0, 0)
+
+
+def test_interpolate_frame_start_end():
+    frame1 = Frame(Point(0, 0, 0), Vector(1, 0, 0), Vector(0, 1, 0))
+    frame2 = Frame(Point(1, 1, 1), Vector(0, 0, 1), Vector(0, 1, 0))
+
+    # Test interpolation at the start
+    start_frame = frame1.interpolate_frame(frame2, 0)
+    assert start_frame.point == frame1.point and start_frame.xaxis == frame1.xaxis and start_frame.yaxis == frame1.yaxis, "Failed at t=0"
+
+    # Test interpolation at the end
+    end_frame = frame1.interpolate_frame(frame2, 1)
+    assert end_frame.point == frame2.point and end_frame.xaxis == frame2.xaxis and end_frame.yaxis == frame2.yaxis, "Failed at t=1"