Macro MoveToOrigin
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| Description |
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| Moves the selected location of an object to the Origin. This macro translates the Placement of an object so that a selected location becomes its new origin. This may be useful when imported objects from other formats like STL or STEP are inconveniently located for further processing by FreeCAD. Macro version: 00.02 Last modified: 2021-07-07 Download: ToolBar Icon Author: Edwilliams16 |
| Author |
| Edwilliams16 |
| Download |
| ToolBar Icon |
| Links |
| Macros recipes How to install macros How to customize toolbars |
| Macro Version |
| 00.02 |
| Date last modified |
| 2021-07-07 |
| FreeCAD Version(s) |
| None |
| Default shortcut |
| None |
| See also |
| None |
Description
This macro translates the Placement of an object so that a selected location becomes its new origin. This may be useful when imported objects from other formats like STL or STEP are inconveniently located for further processing by FreeCAD.
Usage
- Copy the macro into your Macro Directory. (You can copy and paste into the Macro Editor and save.)
- First select, then run the macro. Undo is available.
The following selections are supported:
-- Single Vertex -- moved to origin
-- Single Line Segment -- mid-point moved to origin
-- Single Circle or Circular Arc -- center moved to origin
-- Single Face -- C.G. moved to origin
-- Single Object -- C.G. moved to origin (supports Solid, Shell, Compound and CompSolid)
-- Three Vertices -- Center of circle through the vertices moved to the origin (useful for tessellated circles)
Macro MoveToOrigin.FCMacro
__Title__ = "MoveToOrigin"
__Author__ = "edwilliams16"
__Version__ = "00.02"
__Date__ = "2021.7.7"
debug = False
'''Usage:
This macro will adjust the placement of a shape to place a selected feature at the origin.
One vertex: - to origin
One line segment - midpoint to origin
One circle - center to origin
One arc of circle - center to origin
One face - CG of face to origin
Three vertices - center of circle through vertices to origin
Shape - CG of shape to origin
If the shape is a BaseFeature inside a body, the base feature's placement in the body is adjusted.
'''
# Version 0.01 Original
# Version 0.02 - now handles objects in nested part containers
def circumcenter(A, B, C):
'''Return the circumcenter of three 3D vertices'''
a2 = (B - C).Length**2
b2 = (C - A).Length**2
c2 = (A - B).Length**2
if a2 * b2 * c2 == 0.0:
print('Three vertices must be distinct')
return
alpha = a2 * (b2 + c2 - a2)
beta = b2 * (c2 + a2 - b2)
gamma = c2 * (a2 + b2 - c2)
return (alpha*A + beta * B + gamma * C)/(alpha + beta + gamma)
def centerofmass(subshapes):
mass =0.0
moment = App.Vector(0, 0, 0)
for sh in subshapes:
mass += sh.Volume
moment += sh.Volume * sh.CenterOfMass
return moment/mass
def globalCG(obj, removeLocalOffset=True):
'''Find COM of object in global coordinates
remove local offset per https://forum.freecadweb.org/viewtopic.php?t=27821'''
gpl = obj.getGlobalPlacement()
pl = obj.Placement
rpl= gpl.multiply(pl.inverse())
if removeLocalOffset:
return rpl.multVec(obj.Shape.CenterOfMass)
else:
return gpl.multVec(obj.Shape.CenterOfMass)
def globalGCGHierarchy(obj):
''' Compute global COM of an object hierarchy'''
volume= 0
moment = App.Vector(0., 0., 0.)
def wrappedGCG(obj):
nonlocal volume, moment
if hasattr(obj, 'Shape'):
shape = obj.Shape
if hasattr(shape, 'CenterOfMass'):
print(f'{obj.Name} {vectorRound(globalCG(obj, True), nDec)}')
volume += shape.Volume
moment += globalCG(obj, True).multiply(shape.Volume)
else:
for obj1 in obj.OutList:
if hasattr(obj1, 'Shape'):
wrappedGCG(obj1)
wrappedGCG(obj)
return (volume, moment)
def vectorRound(v, n):
'''Round the output of App.Vector v to n dec places'''
return App.Vector(round(v.x, n), round(v.y, n), round(v.z, n))
isGlobal = False
nDec = 3
selt = Gui.Selection.getSelectionEx()
if len(selt) != 1:
print('Select one vertex, edge or object\nor three vertices for center of circle')
shift = App.Vector(0, 0, 0) # bail and do nothing
else:
sel = selt[0]
if sel.HasSubObjects:
vv = sel.SubObjects
if len(vv) ==3 and vv[0].ShapeType == 'Vertex' and vv[1].ShapeType == 'Vertex' and vv[2].ShapeType == 'Vertex':
shift = circumcenter(vv[0].Point, vv[1].Point, vv[2].Point)
if debug: print('Three Vertices')
elif len(vv) == 1:
selected = sel.SubObjects[0]
if selected.ShapeType == 'Vertex':
shift = selected.Point
if debug: print('One vertex')
elif selected.ShapeType == 'Edge':
if selected.Curve.TypeId == 'Part::GeomCircle': #circles and arcs
shift = selected.Curve.Center
if debug: print('One arc')
elif selected.Curve.TypeId == 'Part::GeomLine':
shift = (selected.valueAt(selected.FirstParameter) + selected.valueAt(selected.LastParameter))/2 # mid-point
if debug: print('One line')
else:
print(f'edge is {selected.Curve.TypeId} not handled')
shift = App.Vector(0, 0, 0) # bail and do nothing
elif selected.ShapeType == 'Face':
shift = selected.CenterOfMass #center of face
if debug: print('One face')
else:
print(f'ShapeType {selected.ShapeType} not handled')
shift = App.Vector(0, 0, 0) # bail and do nothing
else:
print('Wrong number of Selections')
shift = App.Vector(0, 0, 0) # bail and do nothing
else:
if debug: print(f'ObjectName is {sel.ObjectName}')
#if sel.ObjectName[0:11] == 'BaseFeature':
if hasattr(sel.Object, 'Shape'):
if debug: print('One solid')
shape = sel.Object.Shape
if shape.ShapeType == 'Solid' or shape.ShapeType == 'Shell':
shift = shape.CenterOfMass
elif shape.ShapeType == 'Compound' or shape.ShapeType == 'CompSolid':
#shift = centerofmass(shape.SubShapes)
vol, mom = globalGCGHierarchy(sel.Object)
shift = mom.multiply(1./vol) # global!
isGlobal = True
#more cases?
else:
print(f'Object ShapeType {sel.Object.Shape.ShapeType} not handled')
shift = App.Vector(0, 0, 0) # bail and do nothing
else:
print(f'{sel.ObjectName} is not a shape')
shift = App.Vector(0, 0, 0) # bail and do nothing
pl = App.ActiveDocument.getObject(sel.ObjectName).Placement
gpl = App.ActiveDocument.getObject(sel.ObjectName).getGlobalPlacement()
gplr = gpl.multiply(pl.inverse())
if isGlobal:
shift = gplr.inverse().multVec(shift) # global shift in LCS
print(f'Shift = {vectorRound(shift,nDec)}')
locorigin = gplr.inverse().multVec(App.Vector(0., 0., 0.)) #global origin in LCS
App.ActiveDocument.openTransaction('Undo Move to Origin')
App.ActiveDocument.getObject(sel.ObjectName).Placement.move(locorigin-shift)
App.ActiveDocument.commitTransaction()
App.ActiveDocument.recompute()
Link
The discussion forum MoveToOrigin Macro