MantisBT - VTK
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IDProjectCategoryView StatusDate SubmittedLast Update
0012751VTK(No Category)public2011-11-28 16:542015-12-01 10:21
ReporterPhilippe Pebay 
Assigned ToBerk Geveci 
PriorityurgentSeverityminorReproducibilityhave not tried
StatusclosedResolutionnot fixable 
PlatformOSOS Version
Product Version 
Target VersionFixed in Version 
ProjectKitware
Typeincorrect functionality
Summary0012751: vtkArcSource does not draw correctly arcs with angular sector of 180°
DescriptionThis script allows for the reproduction of the bug:

############################################################
from vtk import *
############################################################

# Create sources
arc = vtkArcSource()
arc.SetCenter( 0, 0, 0 )
arc.SetPoint1( 1, 0, 0 )
arc.SetPoint2( -1, 0, 0 )
arc.SetResolution( 32 )
sphere = vtkSphereSource()
sphere.SetRadius( 0.05 )
sphere.SetCenter( 0, 0, 0 )
sphere.SetPhiResolution( 16 )
sphere.SetThetaResolution( 16 )

# Create mappers
mapper1 = vtkPolyDataMapper()
mapper1.SetInput( arc.GetOutput() )

mapper2 = vtkPolyDataMapper()
mapper2.SetInputConnection( sphere.GetOutputPort() )

# Create actors
actor1 = vtkActor()
actor1.SetMapper( mapper1 )
actor1.GetProperty().SetColor( 1., 0., 0. )
actor2 = vtkActor()
actor2.SetMapper( mapper2 )

# Create renderer
renderer = vtkRenderer()
renderer.AddViewProp( actor1 )
renderer.AddViewProp( actor2 )
renderer.SetBackground( .3, .4 ,.5 )

# Create render window
window = vtkRenderWindow()
window.AddRenderer( renderer )
window.SetSize( 500, 500 )

# Create interactor
interactor = vtkRenderWindowInteractor()
interactor.SetRenderWindow( window )

# Start interaction
window.Render()
interactor.Start()
                                                                 
Steps To Reproduce
Additional Information
TagsNo tags attached.
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Attached Filespng Incorrect180DegreesArc.png (18,991) 2011-11-28 16:54
https://www.vtk.org/Bug/file/9076/Incorrect180DegreesArc.png
png
Issue History
Date ModifiedUsernameFieldChange
2011-11-28 16:54Philippe PebayNew Issue
2011-11-28 16:54Philippe PebayStatusbacklog => tabled
2011-11-28 16:54Philippe PebayAssigned To => Berk Geveci
2011-11-28 16:54Philippe PebayFile Added: Incorrect180DegreesArc.png
2013-07-22 20:03Dave DeMarleStatustabled => backlog
2013-07-22 20:03Dave DeMarleNote Added: 0031262
2014-10-02 12:48Cory QuammenNote Added: 0033482
2015-11-10 05:20Waldir PimentaNote Added: 0035440
2015-11-10 05:33Waldir PimentaNote Edited: 0035440bug_revision_view_page.php?bugnote_id=35440#r1387
2015-12-01 10:21Cory QuammenNote Added: 0035493
2015-12-01 10:21Cory QuammenStatusbacklog => closed
2015-12-01 10:21Cory QuammenResolutionopen => not fixable

Notes
(0031262)
Dave DeMarle   
2013-07-22 20:03   
moving all "tabled" bugs into "backlog" category since "tabled" is no longer used.
(0033482)
Cory Quammen   
2014-10-02 12:48   
Verified this behavior.

I don't know what the solution should be. The problem is that the line segments from the center to both points are colinear, so an infinite number of planes contains the points. Which one do you pick to use for the plane of the arc? Which side of the colinear line segments in that plane do you want to place the arc?
(0035440)
Waldir Pimenta   
2015-11-10 05:20   
(edited on: 2015-11-10 05:33)
I think this bug should be closed as invalid, since the problem is not with the software (which does the only possible reasonable thing in this case), but with an ill-defined problem with infinite solutions.

In fact, I would suggest this interface to be deprecated, now that the alternative interface of UseNormalAndAngle is available, which is more intuitive and less susceptible to such unsolvable parametrizations. Or at least the UseNormalAndAngle interface should be made the default, rather than the opposite. What would be necessary to implement such a change? I'm willing to help in the transition if there's agreement that it's the right course of action.
(0035493)
Cory Quammen   
2015-12-01 10:21   
I agree with closing the bug.

I don't think we should deprecate the methods in questions because they cab be convenient for some set of users. I also don't think we should change the default for UseNormalAndAngle because doing so could break existing code.