[Bug report] Failure to compute iso-line for NURBS surface

DRAW reproducer:
> pload MODELING
> restore s.rle s
> uiso u s 0.5
An exception was caught 005656AC : Standard_ConstructionError: Geom_BSplineCurve

** Exception ** 005656AC : Standard_ConstructionError: Geom_BSplineCurve

For creating a B-Spline curve the negative weights are supplied what causes an exception.
Tested on OCC 6.5.0 and 6.5.1, Windows, 32 bit.

Forum supervisor's picture

Dear Roman,
I would like to inform you that the posted problem has been checked and confirmed.
As you probably know the website dedicated to contributors is available now: http://dev.opencascade.org.
We suggest you to make a contribution via the Collaborative portal.
For bugs registration Mantis Bugtracker is available now.

Roman Lygin's picture


Thank you for a recommendation.
I sort of intentionally continue to use this forum for bug reports instead of bug tracker as it enables follow-up discussion right here and triggers an immediate email.
The tracker does allow rss subsription but not sure if there is any discussion possible. Is it ? A custom emailing mechanism (immediate, daily, weekly) would be very much helpful (just like one used in the google groups like oce-dev).

In addition, this forum is a huge time saver (2 clicks without attachment and 4 with it :-; ). Searching is also more convenient (one click away). All this makes this forum more productive.

Don't take this as whining, it's just a natural reluctance to lose a tool you had been fed for 12+ years ;-).

But your thoughts on the user experience/productivity issues would be helpful, to encourage proper direct use of Mantis.


Denis Barbier's picture

> A custom emailing mechanism (immediate, daily, weekly) would be very much helpful

Immediate delivery is available, click on My Account, then Preferences.

lishu2006's picture


Forum supervisor's picture


Let me ask you a question - what is your goal when reporting a bug: having it discussed (then it is logical to use the forum) or get it fixed / integrated?

In the latter case, we would still advise that you use the bug tracker, since this is what it is tailored for. Direct use of the tracker makes the bug advancement process faster, and provides necessary features to track its progress.

Using the tracker, you will get immediate mail notifications when something happens with the issue; you can also add other users to the notification list and run a relevant discussion using the issue notes.

The only feature that the forum has but the tracker lacks is that the tracker does not broadcast each message to the whole community.

But does everybody need this, really?

Forum Supervisor

Roman Lygin's picture

OK. The Mantis tracker will probably make it better indeed.
So I went and reported the bug there, then corrected the reproducer (after own further analysis) and finally provided a fix ;-).
With subscription to the notifications, it should be easier to track your internal progress and as such should provide more transparency into the status.

Thanks again,

Roman Lygin's picture

Sorry, forgot to add a cross-reference - http://tracker.dev.opencascade.org/view.php?id=22910