Macro BSurf from grid
|
|
| Description |
|---|
| Makes a B-spline surface through a grid of points. Macro version: 0.1 Last modified: 2022-07-31 Author: heda |
| Author |
| heda |
| Download |
| None |
| Links |
| Macros recipes How to install macros How to customize toolbars |
| Macro Version |
| 0.1 |
| Date last modified |
| 2022-07-31 |
| FreeCAD Version(s) |
| None |
| Default shortcut |
| None |
| See also |
| None |
Description
Makes a B-spline surface through a grid of points. Options for only creating Wire or B-spline curves.
Macro BSurf from grid
Installation
Available in the Addon manager.
Options
See docstring.
Usage
See docstring.
Script
Macro_BSurf_from_grid.FCMacro
# -*- coding: utf-8 -*-
# ***************************************************************************
# * *
# * Copyright (c) 2022 - heda <heda@fc-forum> *
# * *
# * This program is free software; you can redistribute it and/or modify *
# * it under the terms of the GNU Lesser General Public License (LGPL) *
# * as published by the Free Software Foundation; either version 2 of *
# * the License, or (at your option) any later version. *
# * for detail see the LICENCE text file. *
# * *
# * This program is distributed in the hope that it will be useful, *
# * but WITHOUT ANY WARRANTY; without even the implied warranty of *
# * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
# * GNU Library General Public License for more details. *
# * *
# * You should have received a copy of the GNU Library General Public *
# * License along with this program; if not, write to the Free Software *
# * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 *
# * USA *
# * *
# ***************************************************************************
__Name__ = 'BSurf_from_grid'
__Comment__ = 'Makes a BSpline surface through a grid of points.'
__Author__ = 'heda'
__Version__ = '0.1'
__Date__ = '2022-07-31'
__License__ = 'LGPL-2.0-or-later'
__Web__ = ''
__Wiki__ = 'https://wiki.freecad.org/Macro_Grid_2_BSurf'
__Icon__ = ''
__Help__ = 'Select structured point-cloud, set options, run macro'
__Status__ = 'functional'
__Requires__ = ''
__Communication__ = ''
__Files__ = ''
"""
inspired by:
https://forum.freecadweb.org/viewtopic.php?f=22&t=69941&start=10
cred to snow54
it is assumed that the cloud is:
- structured
- aligned with xy grid,
i.e. a constant y divides 2 horizontal rows of points,
analogue for x and vertical columns of points
usage:
select a pointcloud and run macro
options:
wires: convert boundary wires to spline (draft wb),
in surf wb, use boundry edges and verts on wires as vertex-constraints
splines: in surf wb, use outer contour as boundry edges,
inner edges can be used as edge constraints
bsurf: surface directly created with poles/knots from interpolated spline
mkwframe: in case of bsurf, symbolic wireframe of splines (draft wb)
"""
import numpy as np
from scipy import interpolate
import FreeCAD as App
import FreeCADGui as Gui
import Draft, Part
Vector = App.Vector
doc = App.ActiveDocument
try:
cloud, = Gui.Selection.getSelection()
except ValueError as e:
raise RuntimeWarning('a point cloud needs to be selected.')
points = cloud.Points.Points
bb = cloud.Points.BoundBox
options = o = dict(MakeWires=False,
MakeBSplines=False,
MakeBSurf=True,
MakeWFrame=True)
## a bit of options logic...
if o['MakeWires']: o['MakeBSplines'] = False
if o['MakeBSplines']: o['MakeBSurf'] = o['MakeWires'] = False
if o['MakeBSurf'] and o['MakeWFrame']:
o['MakeBSplines'] = True; o['MakeWires'] = False
if not o['MakeBSurf']: o['MakeWFrame'] = False
def RGB(*args):
return tuple((float(i/255) for i in args))
hstep = min((p.y for p in points))
vstep = min((p.x for p in points))
wiregroup = doc.addObject('App::DocumentObjectGroup', 'Wires')
hwires = doc.addObject('App::DocumentObjectGroup', 'HWires')
vwires = doc.addObject('App::DocumentObjectGroup', 'VWires')
wiregroup.addObjects([hwires, vwires])
for wg, step, getter in ((hwires, hstep, 'y'),
(vwires, vstep, 'x')):
wires = list()
empty = False
cc = bb.YMin if getter == 'y' else bb.XMin
cc -= step/2
while not empty:
polypoints = list()
for pt in points:
value = getattr(pt, getter)
if cc < value < cc + step:
polypoints.append(pt)
if polypoints:
if o['MakeWires'] or (o['MakeBSurf'] and not o['MakeWFrame']):
maker = Draft.make_wire
elif o['MakeBSplines']:
maker = Draft.make_bspline
wires.append(maker(polypoints, closed=False))
cc += step
else:
empty = True
wg.addObjects(wires)
Gui.Selection.clearSelection()
if o['MakeBSurf']:
degree_u = degree_v = 3
periodic = False
lowerx, lowery = hwires.Group[0], vwires.Group[0]
x = np.array([pt.x for pt in lowerx.Points])
y = np.array([pt.y for pt in lowery.Points])
Z = np.array([[pt.z for pt in hw.Points] for hw in hwires.Group])
## Create spline surface
g = interpolate.RectBivariateSpline(x, y, Z.T)
coefgs = g.get_coeffs()
coefgs = np.reshape(coefgs, Z.T.shape).T
knots = g.get_knots()
# Convert knot vector format
knot_u, mult_u = np.unique(knots[1], return_counts=True)
knot_v, mult_v = np.unique(knots[0], return_counts=True)
# Normalize knot vectors
knot_u = (knot_u - knot_u.min()) / (knot_u.max() - knot_u.min())
knot_v = (knot_v - knot_v.min()) / (knot_v.max() - knot_v.min())
# Calculate spline coefficients for x and y
gx = interpolate.make_interp_spline(x, x)
coefgx = gx.tck[1]
gy = interpolate.make_interp_spline(y, y)
coefgy = gy.tck[1]
getVector = lambda iz, jz: Vector(coefgx[jz],
coefgy[iz],
coefgs[iz, jz])
# Create control point vectors
ctrl = [[getVector(iZ, jZ) for jZ, lc in enumerate(lr)]
for iZ, lr in enumerate(coefgs)]
# Create spline surface in FreeCAD
bs = Part.BSplineSurface()
bs.buildFromPolesMultsKnots(ctrl, mult_u, mult_v, knot_u, knot_v,
periodic, periodic, degree_u, degree_v)
surf = Part.show(bs.toShape(), 'BSplineSurf')
surf.Label2 = 'spline surface through points'
surf.ViewObject.ShapeColor = RGB(0, 170, 255)
if not o['MakeWFrame']:
for obj in hwires.Group + vwires.Group + [hwires, vwires, wiregroup]:
doc.removeObject(obj.Name)
doc.recompute()
av = Gui.ActiveDocument.ActiveView
av.viewIsometric()
av.fitAll()