moved the toolpath generation code to a separate module

renamed configuration setting "overlap" to "overlap_percent"


git-svn-id: https://pycam.svn.sourceforge.net/svnroot/pycam/trunk@326 bbaffbd6-741e-11dd-a85d-61de82d9cad9

Changelog

+Version 0.2.5 - NOT RELEASED
+ * changed name of configuration setting "overlap" to "overlap_percent"
+   (you may need to change this name in your custom config files)
+
 Version 0.2.4 - 2010-04-12
  * added a simple simulation mode for visualizing the material penetration of a toolpath
  * join tangential moves (removes the inner points in a colinear set of adjacent path points)

pycam/Cutters/BaseCutter.py

@@ -9,15 +9,17 @@ class BaseCutter:
     id = 0
     vertical = Point(0,0,-1)
 
-    def __init__(self, radius, location=None, height=10):
+    def __init__(self, radius, location=None, height=None):
         if location is None:
             location = Point(0, 0, 0)
         self.location = location
+        if height is None:
+            height = 10
+        self.height = height
         self.id = BaseCutter.id
         BaseCutter.id += 1
         self.radius = radius
         self.radiussq = radius*radius
-        self.height = height
         self.required_distance = 0
         self.distance_radius = self.radius
         self.distance_radiussq = self.distance_radius * self.distance_radius

pycam/Cutters/__init__.py

@@ -5,3 +5,34 @@ from BaseCutter import BaseCutter
 from SphericalCutter import SphericalCutter
 from CylindricalCutter import CylindricalCutter
 from ToroidalCutter import ToroidalCutter
+
+
+def get_tool_from_settings(tool_settings, height=None):
+    """ get the tool specified by the relevant settings
+
+    The settings must include:
+      - "shape": one of "SphericalCutter", "CylindricalCutter" and
+        "ToroidalCutter"
+      - "radius": the tool radius
+    The following settings are optional or shape specific:
+      - "torus_radius": necessary for ToroidalCutter
+
+    @type tool_settings: dict
+    @value tool_settings: contains the attributes of the tool
+    @type height: float
+    @value height: the height of the tool
+    @rtype: BaseCutter | basestring
+    @return: a tool object or an error string
+    """
+    cuttername = tool_settings["shape"]
+    radius = tool_settings["radius"]
+    if cuttername == "SphericalCutter":
+        return SphericalCutter(radius, height=height)
+    elif cuttername == "CylindricalCutter":
+        return CylindricalCutter(radius, height=height)
+    elif cuttername == "ToroidalCutter":
+        toroid = tool_settings["torus_radius"]
+        return ToroidalCutter(radius, toroid, height=height)
+    else:
+        return "Invalid cutter shape: '%s' is not one of %s" % (cuttername, TOOL_SHAPES)
+

pycam/Gui/Project.py

@@ -7,8 +7,7 @@ import pycam.Exporters.EMCToolExporter
 import pycam.Gui.Settings
 import pycam.Gui.common as GuiCommon
 import pycam.Cutters
-import pycam.PathGenerators
-import pycam.PathProcessors
+import pycam.Toolpath.Generator
 import pycam.Toolpath
 import pycam.Geometry.utils as utils
 from pycam.Gui.OpenGLTools import ModelViewWindowGL
@@ -152,7 +151,6 @@ class ProjectGui:
         # set defaults
         self.model = None
         self.toolpath = pycam.Toolpath.ToolPathList()
-        self._physics_cache = None
         self.cutter = None
         self.process_list = []
         self.tool_list = []
@@ -402,14 +400,6 @@ class ProjectGui:
                 self.view3d.glsetup()
             self.view3d.paint()
 
-    def get_physics(self, cutter):
-        if self.settings.get("enable_ode"):
-            self._physics_cache = pycam.Physics.ode_physics.generate_physics(self.model,
-                    cutter, self._physics_cache)
-        else:
-            self._physics_cache = None
-        return self._physics_cache
-
     def update_save_actions(self):
         self.gui.get_object("SaveTaskSettings").set_sensitive(not self.last_task_settings_file is None)
         self.gui.get_object("SaveModel").set_sensitive(not self.last_model_file is None)
@@ -447,7 +437,7 @@ class ProjectGui:
             lines.append(tool_desc)
             lines.append("Speed: %d/minute / Feedrate: %d%s/minute" % (tool["speed"], tool["feedrate"], unit))
             lines.append("Path: %s / %s" % (process["path_generator"], process["path_postprocessor"]))
-            lines.append("Overlap: %d%%" % process["overlap"])
+            lines.append("Overlap: %d%%" % process["overlap_percent"])
             lines.append("Material allowance: %.2f%s" % (process["material_allowance"], unit))
             if process["path_generator"] == "PushCutter":
                 lines.append("Maximum step down: %.2f%s" % (process["step_down"], unit))
@@ -1174,7 +1164,7 @@ class ProjectGui:
                     return name
         settings["path_postprocessor"] = get_path_postprocessor()
         for objname, key in (("SafetyHeightControl", "safety_height"),
-                ("OverlapPercentControl", "overlap"),
+                ("OverlapPercentControl", "overlap_percent"),
                 ("MaterialAllowanceControl", "material_allowance"),
                 ("MaxStepDownControl", "step_down")):
             settings[key] = self.gui.get_object(objname).get_value()
@@ -1197,7 +1187,7 @@ class ProjectGui:
             self.gui.get_object(value).set_active(True)
         set_path_postprocessor(settings["path_postprocessor"])
         for objname, key in (("SafetyHeightControl", "safety_height"),
-                ("OverlapPercentControl", "overlap"),
+                ("OverlapPercentControl", "overlap_percent"),
                 ("MaterialAllowanceControl", "material_allowance"),
                 ("MaxStepDownControl", "step_down")):
             self.gui.get_object(objname).set_value(settings[key])
@@ -1314,8 +1304,8 @@ class ProjectGui:
             # columns: name, visible, drill_size, drill_id, allowance, speed, feedrate
             for index in range(len(self.toolpath)):
                 tp = self.toolpath[index]
-                items = (index, tp.name, tp.visible, tp.drill_size,
-                        tp.drill_id, tp.material_allowance, tp.speed, tp.feedrate)
+                items = (index, tp.name, tp.visible, tp.tool_settings["radius"],
+                        tp.tool_id, tp.material_allowance, tp.speed, tp.feedrate)
                 model.append(items)
             if not new_index is None:
                 self._treeview_set_active_index(self.toolpath_table, new_index)
@@ -1346,58 +1336,6 @@ class ProjectGui:
         if not settings.write_to_file(filename, self.tool_list, self.process_list, self.task_list) and not no_dialog and not self.no_dialog:
             show_error_dialog(self.window, "Failed to save settings file")
 
-    def get_tool_instance(self, tool_settings):
-        cutter_height = self.settings.get("maxz") - self.settings.get("minz")
-        if self.model:
-            cutter_height = max(cutter_height, self.model.maxz - self.model.minz)
-        # Due to some weirdness the height of the drill must be bigger than the object's size.
-        # Otherwise some collisions are not detected.
-        cutter_height *= 4
-        cuttername = tool_settings["shape"]
-        radius = tool_settings["tool_radius"]
-        if cuttername == "SphericalCutter":
-            cutter = pycam.Cutters.SphericalCutter(radius, height=cutter_height)
-        elif cuttername == "CylindricalCutter":
-            cutter = pycam.Cutters.CylindricalCutter(radius, height=cutter_height)
-        elif cuttername == "ToroidalCutter":
-            toroid = tool_settings["torus_radius"]
-            cutter = pycam.Cutters.ToroidalCutter(radius, toroid, height=cutter_height)
-        else:
-            pass
-        return cutter
-
-    def get_pathgenerator_instance(self, cutter, process_settings):
-        pathgenerator = process_settings["path_generator"]
-        pathprocessor = process_settings["path_postprocessor"]
-        cutter.set_required_distance(process_settings["material_allowance"])
-        physics = self.get_physics(cutter)
-        if pathgenerator == "DropCutter":
-            if pathprocessor == "ZigZagCutter":
-                processor = pycam.PathProcessors.PathAccumulator(zigzag=True)
-            else:
-                processor = None
-            result = pycam.PathGenerators.DropCutter(cutter,
-                    self.model, processor, physics=physics,
-                    safety_height=self.settings.get("safety_height"))
-        elif pathgenerator == "PushCutter":
-            if pathprocessor == "PathAccumulator":
-                processor = pycam.PathProcessors.PathAccumulator()
-            elif pathprocessor == "SimpleCutter":
-                processor = pycam.PathProcessors.SimpleCutter()
-            elif pathprocessor == "ZigZagCutter":
-                processor = pycam.PathProcessors.ZigZagCutter()
-            elif pathprocessor == "PolygonCutter":
-                processor = pycam.PathProcessors.PolygonCutter()
-            elif pathprocessor == "ContourCutter":
-                processor = pycam.PathProcessors.ContourCutter()
-            else:
-                processor = None
-            result = pycam.PathGenerators.PushCutter(cutter,
-                    self.model, processor, physics=physics)
-        else:
-            result = None
-        return result
-
     def toggle_progress_bar(self, status):
         if status:
             self.task_pane.set_sensitive(False)
@@ -1435,6 +1373,8 @@ class ProjectGui:
             else:
                 toolpath = self.toolpath[toolpath_index]
         paths = toolpath.get_path()
+        # set the current cutter
+        self.cutter = pycam.Cutters.get_tool_from_settings(toolpath.tool_settings)
         # calculate steps
         detail_level = self.gui.get_object("SimulationDetailsValue").get_value()
         grid_size = 100 * pow(2, detail_level - 1)
@@ -1443,7 +1383,7 @@ class ProjectGui:
         x_steps = int(math.sqrt(grid_size) * proportion)
         y_steps = int(math.sqrt(grid_size) / proportion)
         simulation_backend = pycam.Simulation.ODEBlocks.ODEBlocks(
-                toolpath.drill, toolpath.bounding_box,
+                toolpath.tool_settings, toolpath.bounding_box,
                 x_steps=x_steps, y_steps=y_steps)
         self.settings.set("simulation_object", simulation_backend)
         # disable the simulation widget (avoids confusion regarding "cancel")
@@ -1516,10 +1456,13 @@ class ProjectGui:
             callback = None
         draw_callback = UpdateView(callback,
                 max_fps=self.settings.get("drill_progress_max_fps")).update
-        direction = process_settings["path_direction"]
 
         self.update_progress_bar("Generating collision model")
-        self.cutter = self.get_tool_instance(tool_settings)
+
+        if self.settings.get("enable_ode"):
+            calculation_backend = "ODE"
+        else:
+            calculation_backend = None
 
         # this offset allows to cut a model with a minimal boundary box correctly
         offset = tool_settings["tool_radius"] / 2.0
@@ -1543,6 +1486,7 @@ class ProjectGui:
         maxy = float(self.settings.get("maxy"))+offset
         minz = float(self.settings.get("minz"))
         maxz = float(self.settings.get("maxz"))
+        bounds = (minx, maxx, miny, maxy, minz, maxz)
 
         # check if the boundary limits are valid
         if (minx > maxx) or (miny > maxy) or (minz > maxz):
@@ -1551,70 +1495,57 @@ class ProjectGui:
                 show_error_dialog(self.window, "Processing boundaries are too small for this tool size.")
             return True
 
-        effective_toolradius = tool_settings["tool_radius"] * (1.0 - process_settings["overlap"] / 100.0)
-        x_shift = effective_toolradius
-        y_shift = effective_toolradius
-
         self.update_progress_bar("Starting the toolpath generation")
+        # put the tool settings together
+        tool_dict = {"shape": tool_settings["shape"],
+                "radius": tool_settings["tool_radius"],
+                "torus_radius": tool_settings["torus_radius"],
+        }
+        # run the toolpath generation
+        toolpath = pycam.Toolpath.Generator.generate_toolpath(self.model,
+                tool_dict, bounds=bounds,
+                direction=process_settings["path_direction"],
+                path_generator=process_settings["path_generator"],
+                path_postprocessor=process_settings["path_postprocessor"],
+                material_allowance=process_settings["material_allowance"],
+                safety_height=process_settings["safety_height"],
+                overlap=process_settings["overlap_percent"] / 100.0,
+                step_down=process_settings["step_down"],
+                calculation_backend=calculation_backend, callback=draw_callback)
 
-        pathgenerator = self.get_pathgenerator_instance(self.cutter, process_settings)
-
-        pathgenerator_name = process_settings["path_generator"]
-        if pathgenerator_name == "DropCutter":
-            dx = x_shift
-            dy = y_shift
-            if direction == "x":
-                toolpath = pathgenerator.GenerateToolPath(minx, maxx, miny, maxy, minz, maxz, dx, dy, 0, draw_callback)
-            elif direction == "y":
-                toolpath = pathgenerator.GenerateToolPath(minx, maxx, miny, maxy, minz, maxz, dy, dx, 1, draw_callback)
+        print "Time elapsed: %f" % (time.time() - start_time)
 
-        elif pathgenerator_name == "PushCutter":
-            if process_settings["path_postprocessor"] == "ContourCutter":
-                dx = x_shift
-            else:
-                dx = utils.INFINITE
-            dy = y_shift
-            if process_settings["step_down"] > 0:
-                dz = process_settings["step_down"]
+        if isinstance(toolpath, basestring):
+            # an error occoured - "toolpath" contains the error message
+            message = "Failed to generate toolpath: %s" % toolpath
+            if not self.no_dialog:
+                show_error_dialog(self.window, message)
             else:
-                dz = utils.INFINITE
-            if direction == "x":
-                toolpath = pathgenerator.GenerateToolPath(minx, maxx, miny, maxy, minz, maxz, 0, dy, dz, draw_callback)
-            elif direction == "y":
-                toolpath = pathgenerator.GenerateToolPath(minx, maxx, miny, maxy, minz, maxz, dy, 0, dz, draw_callback)
-            elif direction == "xy":
-                toolpath = pathgenerator.GenerateToolPath(minx, maxx, miny, maxy, minz, maxz, dy, dy, dz, draw_callback)
-        print "Time elapsed: %f" % (time.time() - start_time)
-        # calculate the z offset for the starting position
-        # TODO: fix these hard-coded offsets; maybe use the safety height instead?
-        if self.settings.get("unit") == 'mm':
-            start_offset = 7.0
+                print >>sys.stderr, message
+            # we were not successful (similar to a "cancel" request)
+            return False
         else:
-            start_offset = 0.25
-        # hide the previous toolpath if it is the only visible one (automatic mode)
-        if (len([True for path in self.toolpath if path.visible]) == 1) \
-                and self.toolpath[-1].visible:
-            self.toolpath[-1].visible = False
-        # add the new toolpath
-        description = "%s / %s" % (tool_settings["name"], process_settings["name"])
-        # the tool id numbering should start with 1 instead of zero
-        tool_id = self.tool_list.index(tool_settings) + 1
-        bounding_box = (self.settings.get("minx"), self.settings.get("maxx"),
-                self.settings.get("miny"), self.settings.get("maxy"),
-                self.settings.get("minz"), self.settings.get("maxz"))
-        self.toolpath.add_toolpath(toolpath,
-                description, self.cutter, tool_id,
-                tool_settings["speed"],
-                tool_settings["feedrate"],
-                process_settings["material_allowance"],
-                process_settings["safety_height"],
-                self.settings.get("unit"),
-                minx, miny, maxz + start_offset,
-                bounding_box)
-        self.update_toolpath_table()
-        self.update_view()
-        # return "False" if the action was cancelled
-        return not self._progress_cancel_requested
+            # hide the previous toolpath if it is the only visible one (automatic mode)
+            if (len([True for path in self.toolpath if path.visible]) == 1) \
+                    and self.toolpath[-1].visible:
+                self.toolpath[-1].visible = False
+            # add the new toolpath
+            description = "%s / %s" % (tool_settings["name"], process_settings["name"])
+            # the tool id numbering should start with 1 instead of zero
+            tool_id = self.tool_list.index(tool_settings) + 1
+            self.toolpath.add_toolpath(toolpath,
+                    description, tool_dict, tool_id,
+                    tool_settings["speed"],
+                    tool_settings["feedrate"],
+                    process_settings["material_allowance"],
+                    process_settings["safety_height"],
+                    self.settings.get("unit"),
+                    minx, miny, process_settings["safety_height"],
+                    bounds)
+            self.update_toolpath_table()
+            self.update_view()
+            # return "False" if the action was cancelled
+            return not self._progress_cancel_requested
 
     def get_filename_via_dialog(self, title, mode_load=False, type_filter=None):
         # we open a dialog
@@ -1727,7 +1658,7 @@ class ProjectGui:
                 pycam.Exporters.SimpleGCodeExporter.ExportPathList(destination,
                         tp.toolpath, tp.unit,
                         tp.start_x, tp.start_y, tp.start_z,
-                        tp.feedrate, tp.speed, tp.safety_height, tp.drill_id,
+                        tp.feedrate, tp.speed, tp.safety_height, tp.tool_id,
                         finish_program=is_last_loop)
             destination.close()
             if self.no_dialog:

pycam/Gui/Settings.py

@@ -120,7 +120,7 @@ path_generator: PushCutter
 path_postprocessor: PolygonCutter
 material_allowance: 0.5
 step_down: 0.8
-overlap: 0
+overlap_percent: 0
 
 [Process1]
 name: Semi-finish
@@ -128,7 +128,7 @@ path_generator: PushCutter
 path_postprocessor: ContourCutter
 material_allowance: 0.2
 step_down: 0.5
-overlap: 20
+overlap_percent: 20
 
 [Process2]
 name: Finish
@@ -136,7 +136,7 @@ path_generator: DropCutter
 path_postprocessor: ZigZagCutter
 material_allowance: 0.0
 step_down: 1.0
-overlap: 60
+overlap_percent: 60
 
 [TaskDefault]
 enabled: 1
@@ -166,7 +166,7 @@ process: 2
             "path_postprocessor": str,
             "safety_height": float,
             "material_allowance": float,
-            "overlap": int,
+            "overlap_percent": int,
             "step_down": float,
             "tool": object,
             "process": object,
@@ -182,7 +182,7 @@ process: 2
     CATEGORY_KEYS = {
             "tool": ("name", "shape", "tool_radius", "torus_radius", "feedrate", "speed"),
             "process": ("name", "path_generator", "path_postprocessor", "path_direction",
-                    "safety_height", "material_allowance", "overlap", "step_down"),
+                    "safety_height", "material_allowance", "overlap_percent", "step_down"),
             "task": ("tool", "process", "enabled"),
     }
 

pycam/Simulation/ODEBlocks.py

+import pycam.Cutters
 from pycam.Geometry.Point import Point
 import ode
 try:
@@ -8,8 +9,8 @@ except:
 
 class ODEBlocks:
 
-    def __init__(self, cutter, (minx, maxx, miny, maxy, minz, maxz), x_steps=None, y_steps=None):
-        self.cutter = cutter
+    def __init__(self, tool_settings, (minx, maxx, miny, maxy, minz, maxz), x_steps=None, y_steps=None):
+        self.cutter = pycam.Cutters.get_tool_from_settings(tool_settings)
         # we don't want to use the "material allowance" distance
         self.cutter.set_required_distance(0)
         dimx = maxx - minx

pycam/Toolpath/Generator.py

+import pycam.PathGenerators
+import pycam.PathProcessors
+import pycam.Cutters
+import sys
+
+DIRECTIONS = frozenset(("x", "y", "xy"))
+PATH_GENERATORS = frozenset(("DropCutter", "PushCutter"))
+PATH_POSTPROCESSORS = frozenset(("ContourCutter", "PathAccumulator", "PolygonCutter", "SimpleCutter", "ZigZagCutter"))
+CALCULATION_BACKENDS = frozenset((None, "ODE"))
+
+def generate_toolpath(model, tool_settings=None, bounds=None, direction="x",
+        path_generator="DropCutter", path_postprocessor="ZigZagCutter",
+        material_allowance=0.0, safety_height=None, overlap=0.0,
+        step_down=0.0, calculation_backend=None, callback=None):
+    """ abstract interface for generating a toolpath
+
+    @type model: pycam.Geometry.Model.Model
+    @value model: a model contains the surface triangles
+    @type direction: str
+    @value direction: any member of the DIRECTIONS set (e.g. "x", "y" or "xy")
+    @type bounds: tuple(float) | list(float)
+    @value bounds: the processing boundary (relative to the center of the tool)
+        (order: minx, maxx, miny, maxy, minz, maxz)
+    @type tool_settings: dict
+    @value tool_settings: contains at least the following keys (depending on
+        the tool type):
+        "shape": any of possible cutter shape (see "pycam.Cutters")
+        "radius": main radius of the tools
+        "torus_radius": (only for ToroidalCutter) second toroidal radius
+    @type path_generator: str
+    @value path_generator: any member of the PATH_GENERATORS set
+    @type path_postprocessor: str
+    @value path_postprocessor: any member of the PATH_POSTPROCESSORS set
+    @type material_allowance: float
+    @value material_allowance: the minimum distance between the tool and the model
+    @type overlap: float
+    @value overlap: the overlap between two adjacent tool paths (0 <= overlap < 1)
+    @type calculation_backend: str | None
+    @value calculation_backend: any member of the CALCULATION_BACKENDS set
+        The default is the triangular collision detection.
+    @rtype: pycam.Toolpath.ToolPath | str
+    @return: the resulting toolpath object or an error string in case of invalid
+        arguments
+    """
+    if bounds is None:
+        # no bounds were given - we use the boundaries of the model
+        minx, maxx = model.minx, model.maxx
+        miny, maxy = model.miny, model.maxy
+        minz, maxz = model.minz, model.maxz
+    else:
+        minx, maxx, miny, maxy, minz, maxz = bounds
+    # Due to some weirdness the height of the drill must be bigger than the object's size.
+    # Otherwise some collisions are not detected.
+    cutter_height = 4 * (maxy - miny)
+    cutter = pycam.Cutters.get_tool_from_settings(tool_settings, cutter_height)
+    if isinstance(cutter, basestring):
+        return cutter
+    cutter.set_required_distance(material_allowance)
+    physics = _get_physics(cutter, calculation_backend)
+    if isinstance(physics, basestring):
+        return physics
+    generator = _get_pathgenerator_instance(model, cutter, path_generator, path_postprocessor, material_allowance, safety_height, physics)
+    if isinstance(generator, basestring):
+        return generator
+    if (overlap < 0) or (overlap >= 1):
+        return "Invalid overlap value (%f): should be greater or equal 0 and lower than 1"
+    effective_toolradius = tool_settings["radius"] * (1.0 - overlap)
+    if path_generator == "DropCutter":
+        if direction == "x":
+            direction_param = 0
+        elif direction == "y":
+            direction_param = 1
+        else:
+            return "Invalid direction value (%s): not one of %s" % (direction, DIRECTIONS)
+        toolpath = generator.GenerateToolPath(minx, maxx, miny, maxy, minz, maxz,
+                effective_toolradius, effective_toolradius, direction_param, callback)
+    else:
+        if step_down > 0:
+            dz = step_down
+        else:
+            dz = maxz - minz
+        if direction == "x":
+            dx, dy = 0, effective_toolradius
+        elif direction == "y":
+            dx, dy = effective_toolradius, 0
+        elif direction == "xy":
+            dx, dy = effective_toolradius, effective_toolradius
+        else:
+            return "Invalid direction (%s): not one of %s" % (direction, DIRECTIONS)
+        toolpath = generator.GenerateToolPath(minx, maxx, miny, maxy, minz, maxz, dx, dy, dz, callback)
+    return toolpath
+    
+def _get_pathgenerator_instance(model, cutter, pathgenerator, pathprocessor,
+        material_allowance, safety_height, physics):
+    if pathgenerator == "DropCutter":
+        if pathprocessor == "ZigZagCutter":
+            processor = pycam.PathProcessors.PathAccumulator(zigzag=True)
+        elif pathprocessor == "PathAccumulator":
+            processor = pycam.PathProcessors.PathAccumulator()
+        else:
+            return "Invalid postprocessor (%s) for 'DropCutter': only 'ZigZagCutter' or 'PathAccumulator' are allowed" % str(pathprocessor)
+        return pycam.PathGenerators.DropCutter(cutter,
+                model, processor, physics=physics,
+                safety_height=safety_height)
+    elif pathgenerator == "PushCutter":
+        if pathprocessor == "PathAccumulator":
+            processor = pycam.PathProcessors.PathAccumulator()
+        elif pathprocessor == "SimpleCutter":
+            processor = pycam.PathProcessors.SimpleCutter()
+        elif pathprocessor == "ZigZagCutter":
+            processor = pycam.PathProcessors.ZigZagCutter()
+        elif pathprocessor == "PolygonCutter":
+            processor = pycam.PathProcessors.PolygonCutter()
+        elif pathprocessor == "ContourCutter":
+            processor = pycam.PathProcessors.ContourCutter()
+        else:
+            return "Invalid postprocessor (%s) for 'PushCutter' - it should be one of these: %s" % (processor, PATH_POSTPROCESSORS)
+        return pycam.PathGenerators.PushCutter(cutter,
+                model, processor, physics=physics)
+    else:
+        return "Invalid path generator (%s): not one of %s" % (pathgenerator, PATH_GENERATORS)
+
+def _get_physics(cutter, calculation_backend):
+    if calculation_backend is None:
+        # triangular collision detection does not need any physical model
+        return None
+    elif calculation_backend == "ODE":
+        import pycam.Physics.ode_physics
+        return pycam.Physics.ode_physics.generate_physics(model, cutter)
+    else:
+        return "Invalid calculation backend (%s): not one of %s" % (calculation_backend, CALCULATION_BACKENDS)
+

pycam/Toolpath/__init__.py

+__all__ = ["ToolPathList", "ToolPath", "Generator"]
+
 import random
 
 class ToolPathList(list):
 
-    def add_toolpath(self, toolpath, name, cutter, *args):
-        self.append(ToolPath(toolpath, name, cutter, *args))
+    def add_toolpath(self, toolpath, name, tool_settings, *args):
+        self.append(ToolPath(toolpath, name, tool_settings, *args))
 
 class ToolPath:
 
-    def __init__(self, toolpath, name, cutter, drill_id, speed, feedrate,
-            material_allowance, safety_height, unit, start_x, start_y, start_z, bounding_box):
+    def __init__(self, toolpath, name, tool_settings, tool_id, speed,
+            feedrate, material_allowance, safety_height, unit, start_x,
+            start_y, start_z, bounding_box):
         self.toolpath = toolpath
         self.name = name
         self.visible = True
-        self.drill_id = drill_id
-        self.drill = cutter
-        self.drill_size = cutter.radius
+        self.tool_id = tool_id
+        self.tool_settings = tool_settings
         self.speed = speed
         self.feedrate = feedrate
         self.material_allowance = material_allowance