Macro Shake Sketch

Description
Shake a sketch in order to discover its unconstrained parts. Enter edit mode for a sketch and launch the macro. The macro will add a random noise on all sketch points. The sketch is then solved, constrained parts will retain their position, free parts will move. Always run this macro on a copy of the original sketch.

But be careful working on a copy of your file because the macro "dismantles all" to display and you may need to start over.

Install
Available in Addon manager, or manual install.

Script
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Macro Shake_Sketch.py


 * 1) -*- coding: utf-8 -*-


 * 1) FreeCAD macro to shake a sketch in order to discover its unconstrained parts.
 * 2) A Gaussian noise is introduced in all sketch points and the sketch is then
 * 3) solved.
 * 4) Beware that the sketch can look different because some constraints have
 * 5) several solutions. In this case, just undo.
 * 6) This file is released under the MIT License.
 * 7) Author: Gaël Ecorchard v1.0 & v1.1
 * 8) Author: heda v1.2
 * 9) Version:
 * 10) - 1.2: 2021-10-22
 * 11)       * made macro runnable for current versions of fc
 * 12)       * added Part.LineSegment
 * 13)       * added start info & result dialogue
 * 14)       * hides constraints during shake
 * 15)       * added simple debug printing
 * 16) - 1.1: 2014-10-31
 * 17)       * correct import for Part
 * 18) - 1.0: 2014-08
 * 19)       * first release
 * 1) - 1.0: 2014-08
 * 2)       * first release

__version__ = '1.2' displacement_amplitude = 0.1 debug_print = False title = 'Sketch Shaker Macro (ver: {})'.format(__version__)
 * 1) Amplitude of the point displacements.
 * 2) The standard deviation of the Gaussian noise is the largest sketch dimension
 * 3) multiplied by this factor.


 * 1) End of configuration.

from random import gauss

from PySide.QtGui import QMessageBox

import FreeCADGui as Gui from FreeCAD import Base import Part

print('Running {}'.format(title))

g_geom_points = { Base.Vector: [1], Part.Line: [1, 2], # first point, last point Part.LineSegment: [1, 2], # first point, last point Part.Circle: [0, 3], # curve, center Part.ArcOfCircle: [1, 2, 3], # first point, last point, center } # moves bsplines and conics via lines and circles, no op for Part.Points
 * 1) For each sketch geometry type, map a list of points to move.

def dprint(msg, *args): if debug_print: if args: print(msg.format(*args)) else: print(msg)

class BoundingBox: xmin = xmax = ymin = ymax = None

def enlarge_x(self, x): if self.xmin is None: self.xmin = self.xmax = x       elif self.xmin > x:            self.xmin = x        elif self.xmax < x:            self.xmax = x

def enlarge_y(self, y): if self.ymin is None: self.ymin = self.ymax = y       elif self.ymin > y:            self.ymin = y        elif self.ymax < y:            self.ymax = y

def enlarge_point(self, point): self.enlarge_x(point.x)       self.enlarge_y(point.y)

def enlarge_line(self, line): self.enlarge_x(line.StartPoint.x)       self.enlarge_x(line.EndPoint.x)        self.enlarge_y(line.StartPoint.y)        self.enlarge_y(line.EndPoint.y)

def enlarge_circle(self, circle): self.enlarge_x(circle.Center.x - circle.Radius) self.enlarge_x(circle.Center.x + circle.Radius) self.enlarge_y(circle.Center.y - circle.Radius) self.enlarge_y(circle.Center.y + circle.Radius)

def enlarge_arc_of_circle(self, arc): # TODO: correctly compute the arc extrema (cf. toShape.BoundBox) self.enlarge_x(arc.Center.x)       self.enlarge_y(arc.Center.y)

def get_sketch_dims(sketch): bbox = BoundingBox for geom in sketch.Geometry: if isinstance(geom, Base.Vector): bbox.enlarge_point(geom) elif isinstance(geom, (Part.Line, Part.LineSegment)): bbox.enlarge_line(geom) elif isinstance(geom, Part.Circle): bbox.enlarge_circle(geom) elif isinstance(geom, Part.ArcOfCircle): bbox.enlarge_arc_of_circle(geom) if None in (bbox.xmin, bbox.ymin): dprint('sketch bbox not found') return 0, 0 else: dprint('sketch bbox found') return bbox.xmax - bbox.xmin, bbox.ymax - bbox.ymin

def add_noise(point, sigma): """Add a Gaussian noise with standard deviation sigma""" dprint(' x0:{:>9.3f}  y0:{:>9.3f}', point.x, point.y)    point.x = gauss(point.x, sigma) point.y = gauss(point.y, sigma) dprint(' xt:{:>9.3f}  yt:{:>9.3f}', point.x, point.y)

def move_points(sketch, geom_index, sigma): point_indexes = g_geom_points.get(type(sketch.Geometry[i]), []) # Direct access to sketch.Geometry[index] does not work. This would, # however prevent repeated recompute. # not checked validity of comment for v1.2 moved = False for point_index in point_indexes: dprint(' geo idx [{:>3} ] -- pt idx [{:>3} ] ',              geom_index, point_index) point = sketch.getPoint(geom_index, point_index) add_noise(point, sigma) try: sketch.movePoint(geom_index, point_index, point) except ValueError as e:           dprint(repr(e)) new_pos = sketch.getPoint(geom_index, point_index) test = point.isEqual(new_pos, 0) dprint(' did it move? {}', test) if test: moved = True return moved

def toggle_constraints(sketch, toggle): for cid in toggle: sketch.toggleVirtualSpace(cid)

view_provider = Gui.activeDocument.getInEdit

shake_it = False if not view_provider: msg = 'A sketch needs to be in edit to be shaken.' print(msg) _ = QMessageBox.information(None, title, msg) else: sketch = view_provider.Object if sketch.TypeId == 'Sketcher::SketchObject': sketch.recompute # ensure update to_virtual = [cid for cid, cts in enumerate(sketch.Constraints) if cts.InVirtualSpace] sketch_span = get_sketch_dims(sketch) sigma = max(sketch_span) * displacement_amplitude dprint('sketch span: dx:{:>9.3f} dy:{:>9.3f}', *sketch_span) dprint('sigma for gauss-dist: {:.3f}', sigma) toggle_constraints(sketch, to_virtual) msg = ('Shake sketch will deform the loose parts of the sketch.\n'              'The deformation cannot be undone.\n'               'If that is not desired, click Cancel,\n'               'and run the macro on a copy of the sketch.\n\n'               'Visibility of constraints has been toggled.\n'               'Visibility of constraints is restored'               ' after shaking the sketch.') reply = QMessageBox.information(None, title, msg,                                       QMessageBox.Ok | QMessageBox.Cancel,                                        QMessageBox.Ok) shake_it = reply == QMessageBox.Ok       if not shake_it: toggle_constraints(sketch, to_virtual)

if shake_it: nbr_moves = 0 for i in range(sketch.GeometryCount): did_move = move_points(sketch, i, sigma) if did_move: nbr_moves += 1

msg = 'Did {} moves. Sketch has a total of {} geometry entities.\n\n' msg = msg.format(nbr_moves, sketch.GeometryCount) open_verts = sketch.OpenVertices if open_verts: if len(open_verts) == 1: ov, form = 'one', 'vertex' else: ov, form = len(open_verts), 'vertices' msg += 'Sketch has {} open {}.'.format(ov, form) msg += ('\nA sketch with open vertices'               ' cannot be used to create a solid.') else: msg += 'Sketch is free from open vertices.'

msg += ('\n\nMenu: "Sketch/Validate Sketch..." can be used\n'           'for additional info about sketch status.') _ = QMessageBox.information(None, title, msg) toggle_constraints(sketch, to_virtual) print('Macro finished.')