[Insight-users] Loads in background intentionally nulled

[brian avants]

yes, that is what the LoadBC option does, i believe.

brian




On Thu, Jun 2, 2011 at 11:23 AM, James Gee <gee at exchange.upenn.edu> wrote:
> more traditionally, one would typically update stiffness matrix and load
> vectors directly.  ideally, new framework will maintain transparency to
> allow this option.
>
> On 5/26/11 1:59 PM, "brian avants" <stnava at gmail.com> wrote:
>
>>hi luis
>>
>> you can achieve this in numerous ways via the fem framework.  one
>>approach would be to apply a mask to the image metric which should
>>zero out forces outside the mask ....  though the model will
>>distribute some forces outside of the object.   if you want to totally
>>eliminate background displacements, then you should not mesh it at
>>all.   if you must mesh the background as well, then another approach
>>would be to apply either landmark forces ( mapping a point to itself )
>>and / or  fixed boundary conditions (loadbc).  another option would be
>>to change the material properties of background elements such that
>>they become very stiff.
>>
>>vince may have more recent code examples that illustrate these
>>possibilities,
>>
>>brian
>>
>>
>>
>>
>>On Thu, May 26, 2011 at 1:38 PM, Luis Ibanez <luis.ibanez at kitware.com>
>>wrote:
>>> Hi Brian, Michael,
>>>
>>> Could you advice Jonathan on how to do this in the FEM framework ?\
>>>
>>>
>>>    Thanks
>>>
>>>
>>>         Luis
>>>
>>>
>>> ---------- Forwarded message ----------
>>> From: jonathan grimm <flymolo at gmail.com>
>>> Date: Mon, May 23, 2011 at 5:08 PM
>>> Subject: Re: [Insight-users] Loads in background intentionally nulled
>>> To: insight-users at itk.org
>>>
>>>
>>>
>>> In
>>>http://www.itk.org/CourseWare/Training/NonRigidRegistrationMethods.pdf,
>>> page 80 a case is mentioned where the loads in the background are
>>> intentionally nulled.
>>>
>>> Is example code available for this case or a similar one?
>>>
>>> Does it require a mesh where the background is identified?
>>>
>>> Are there other methods to reduce spurious displacements in low
>>> information areas?
>>>
>>> Thank you for any help,
>>> Jonathan
>>>
>>> --
>>> Sometimes it's hard to tell the dancer from the dance - Corwin in CoC
>>>
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>