template for FFD Cad

Author: ndem0

pygem/__init__.py

@@ -26,6 +26,9 @@ def get_current_year():
 from .rbf import RBF
 from .idw import IDW
 from .rbf_factory import RBFFactory
+
+"""
+"""
 #from .radial import RBF
 #from .idw import IDW
 #from .filehandler import FileHandler

pygem/cad/__init__.py

@@ -1,11 +1,15 @@
 
 try:
-    from .nurbshandler import NurbsHandler
-    from .stephandler import StepHandler
-    from .igeshandler import IgesHandler
+    import OCC
 except ModuleNotFoundError as e:
     print('\nOCC not found, but required to deal with CAD files')
     print('Install it using:')
     print('\tconda install -c conda-forge pythonocc-core=7.4.0')
     print('or visit https://github.com/tpaviot/pythonocc-core for more info\n')
     raise e
+
+
+from .nurbshandler import NurbsHandler
+from .stephandler import StepHandler
+from .igeshandler import IgesHandler
+from .ffd import FFD

pygem/cad/ffd.py

@@ -0,0 +1,130 @@
+"""
+Utilities for performing Free Form Deformation (FFD)
+
+:Theoretical Insight:
+
+    Free Form Deformation is a technique for the efficient, smooth and accurate
+    geometrical parametrization. It has been proposed the first time in
+    *Sederberg, Thomas W., and Scott R. Parry. "Free-form deformation of solid
+    geometric models." ACM SIGGRAPH computer graphics 20.4 (1986): 151-160*. It
+    consists in three different step:
+    
+    - Mapping the physical domain to the reference one with map
+      :math:`\\boldsymbol{\\psi}`.  In the code it is named *transformation*.
+
+    - Moving some control points to deform the lattice with :math:`\\hat{T}`.
+      The movement of the control points is basically the weight (or displacement)
+      :math:`\\boldsymbol{\\mu}` we set in the *parameters file*.
+
+    - Mapping back to the physical domain with map
+      :math:`\\boldsymbol{\\psi}^{-1}`.  In the code it is named
+      *inverse_transformation*.
+
+    FFD map (:math:`T`) is the composition of the three maps, that is
+
+    .. math:: T(\\cdot, \\boldsymbol{\\mu}) = (\\Psi^{-1} \\circ \\hat{T} \\circ
+            \\Psi) (\\cdot, \\boldsymbol{\\mu})
+
+    In this way, every point inside the FFD box changes it position according to
+
+    .. math:: \\boldsymbol{P} = \\boldsymbol{\\psi}^{-1} \\left( \\sum_{l=0}^L
+            \\sum_{m=0}^M \\sum_{n=0}^N
+            \\mathsf{b}_{lmn}(\\boldsymbol{\\psi}(\\boldsymbol{P}_0))
+            \\boldsymbol{\\mu}_{lmn} \\right)
+
+    where :math:`\\mathsf{b}_{lmn}` are Bernstein polynomials.  We improve the
+    traditional version by allowing a rotation of the FFD lattice in order to
+    give more flexibility to the tool.
+    
+    You can try to add more shapes to the lattice to allow more and more
+    involved transformations.
+
+"""
+try:
+    import configparser as configparser
+except ImportError:
+    import ConfigParser as configparser
+import os
+import numpy as np
+from scipy import special
+from OCC.Core.TopoDS import TopoDS_Shape, TopoDS_Compound
+
+from pygem import FFD as OriginalFFD
+
+class FFD(OriginalFFD):
+    """
+    Class that handles the Free Form Deformation on the mesh points.
+
+    :param FFDParameters ffd_parameters: parameters of the Free Form
+        Deformation.
+    :param numpy.ndarray original_mesh_points: coordinates of the original
+        points of the mesh.
+
+    :param list n_control_points: number of control points in the x, y, and z
+        direction. If not provided it is set to [2, 2, 2].
+
+    :cvar numpy.ndarray box_length: dimension of the FFD bounding box, in the
+        x, y and z direction (local coordinate system).
+    :cvar numpy.ndarray box_origin: the x, y and z coordinates of the origin of
+        the FFD bounding box.
+    :cvar numpy.ndarray rot_angle: rotation angle around x, y and z axis of the
+        FFD bounding box.
+    :cvar numpy.ndarray n_control_points: the number of control points in the
+        x, y, and z direction.
+    :cvar numpy.ndarray array_mu_x: collects the displacements (weights) along
+        x, normalized with the box length x.
+    :cvar numpy.ndarray array_mu_y: collects the displacements (weights) along
+        y, normalized with the box length y.
+    :cvar numpy.ndarray array_mu_z: collects the displacements (weights) along
+        z, normalized with the box length z.
+
+    :Example:
+
+        >>> import pygem.freeform as ffd
+        >>> import pygem.params as ffdp
+        >>> import numpy as np
+        >>> ffd = FFD()
+        >>> ffd.read_parameters('tests/test_datasets/parameters_test_ffd_sphere.prm')
+        # TODO
+        >>> new = free_form.modified_mesh_points
+    """
+
+    def __call__(self, obj):
+        """
+        This method performs the deformation on the CAD file.
+        """
+
+        # Manage input
+        if isinstance(obj, str): # if a input filename is passed
+            shape = # extract topo_shape from filename
+        elif isinstance(obj, TopoDS_Shape):
+            shape = obj
+        # Maybe do we need to handle also Compound?
+        else:
+            raise TypeError
+
+       
+        ## SURFACES PHASE #####################################################
+        src_pts = # extract coordinates of surfaces control points
+
+        new_pts = super().__call__(src_pts) # dont touch this line
+
+        # save here the `new_pts` into the shape
+        ## END SURFACES #######################################################
+
+
+
+        ## CURVES PHASE #######################################################
+        src_pts = # extract coordinates of curves control points
+
+        new_pts = super().__call__(src_pts) # dont touch this line
+
+        # save here the `new_pts` into the shape
+        ## END CURVES #########################################################
+
+
+
+        if isinstance(obj, str): # if a input filename is passed
+            # save the shape exactly to the filename, aka `obj`
+        elif isinstance(obj, TopoDS_Shape):
+            return shape