<br>Hi Patrick,<br><br>Thanks for checking on the usage of these methods.<br><br>I agree with both options.<br><br>We should:<br><br>A) Remove the SetRotation()/SetTranslation() methods<br><br> OR<br><br>B) Rename them to explicitly mention that they clear the
<br> other component.<br><br><br>I'm slightly incline towards (B).<br><br><br>Ziv: Do you have a preference between these two options ?<br><br><br><br> Luis<br><br><br><br>------------------------------------------------------------------------------------
<br><div><span class="gmail_quote">On 8/6/07, <b class="gmail_sendername">Patrick Cheng</b> <<a href="mailto:cheng@isis.georgetown.edu">cheng@isis.georgetown.edu</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi Luis and Ziv,<br><br>Making good sandwich is important! We need to be careful that we 'NEVER'<br>set rotation and translation separately in our code, which will erase<br>each other in this case if we follow Luis's solution.
<br><br>I just did a quick search, at least in Tracker code, which deals with<br>all the transform composition, we are using SetTranslationAndRotation()<br>all the time.<br><br>I am wondering if we should provide<br>SetRotation() and SetTranslation() at all?
<br><br>These methods can be misleading, and I am afraid not many people will<br>read the documentation.<br><br>A name like:<br>SetRotationAndClearTranslation()<br>or<br>SetTranslationAndClearRotation()<br>Will be more explicit name.
<br><br>Patrick<br><br><br><br>Luis Ibanez wrote:<br>><br>> Hi Ziv,<br>><br>> Again, the problem with setting them separately is that the time stamp<br>> is shared.<br>><br>> The second setting will override the time stamp of the first setting and
<br>> the Transform<br>> will end up with a Translation component that does not match in time to<br>> the Rotation<br>> component.<br>><br>> E.g. the Translation component may even have expired, and by setting
<br>> only the<br>> Rotation we will extend its validity time artificially. It is like<br>> making a sandwich with<br>> fresh cheese and an expired ham.... the cheese may be good, but the<br>> total sandwich
<br>> has gone bad anyways.<br>><br>> If the pivot calibration is computing both components separately, then<br>> they should only<br>> be stored in an igstkTransform when both Translation and Rotation are<br>
> available, and that<br>> should be done using the SetRotationAndTranslation() method.<br>><br>><br>> Luis<br>><br>><br>> ----------------------------------------------------------------------------
<br>> On 8/6/07, *Ziv Yaniv* < <a href="mailto:zivy@isis.georgetown.edu">zivy@isis.georgetown.edu</a><br>> <mailto:<a href="mailto:zivy@isis.georgetown.edu">zivy@isis.georgetown.edu</a>>> wrote:<br>><br>
> Hi Luis,<br>><br>> Setting rotation and translation separately without resetting the<br>> transformation is reasonable behavior. Pivot calibration for example<br>> only sets the translational part of a transformation. The user can
<br>> set the rotational part after they get the transformation from the<br>> pivot calibration according to prior knowledge (what Patrick is<br>> doing right now). Of course there are many ways to do this
<br>> (composing separate rotation and translation transformations to get<br>> a single transform, or setting the transformation only when you have<br>> both rotation and translation in hand).<br>>
<br>> In any case I view this as an arbitrary choice and my only<br>> preference is that the documentation and implementation match.<br>><br>><br>> Ziv<br>><br>><br>><br>>
<br>> -----Original Message-----<br>> From: "Luis Ibanez" < <a href="mailto:luis.ibanez@kitware.com">luis.ibanez@kitware.com</a><br>> <mailto:<a href="mailto:luis.ibanez@kitware.com">luis.ibanez@kitware.com
</a>>><br>> Sent 8/6/2007 12:41:56 PM<br>> To: "'Ziv Yaniv'" < <a href="mailto:zivy@isis.imac.georgetown.edu">zivy@isis.imac.georgetown.edu</a><br>> <mailto:<a href="mailto:zivy@isis.imac.georgetown.edu">
zivy@isis.imac.georgetown.edu</a>>>, "IGSTK Developers"<br>> <<a href="mailto:igstk-developers@public.kitware.com">igstk-developers@public.kitware.com</a><br>> <mailto:<a href="mailto:igstk-developers@public.kitware.com">
igstk-developers@public.kitware.com</a>>><br>> Subject: igstkTransfrom documentation update & Style problems<br>><br>> Hi Ziv,<br>><br>> Thanks for updating the documentation of the Transform class:
<br>><br>> <a href="http://public.kitware.com/cgi-bin/viewcvs.cgi/Source/igstkTransform.h?root=IGSTK&sortby=date&r2=1.20&r1=1.19">http://public.kitware.com/cgi-bin/viewcvs.cgi/Source/igstkTransform.h?root=IGSTK&sortby=date&r2=1.20&r1=1.19
</a><br>> <<a href="http://public.kitware.com/cgi-bin/viewcvs.cgi/Source/igstkTransform.h?root=IGSTK&sortby=date&r2=1.20&r1=1.19">http://public.kitware.com/cgi-bin/viewcvs.cgi/Source/igstkTransform.h?root=IGSTK&sortby=date&r2=1.20&r1=1.19
</a>><br>><br>> Unfortunately they introduced several coding style violations.<br>> <a href="http://public.kitware.com/IGSTK/Sites/insight.journal.kitware/KWStyle/20070806-0430-Nightly/BuildError.html">
http://public.kitware.com/IGSTK/Sites/insight.journal.kitware/KWStyle/20070806-0430-Nightly/BuildError.html</a><br>> <<a href="http://public.kitware.com/IGSTK/Sites/insight.journal.kitware/KWStyle/20070806-0430-Nightly/BuildError.html">
http://public.kitware.com/IGSTK/Sites/insight.journal.kitware/KWStyle/20070806-0430-Nightly/BuildError.html</a>><br>><br>> Also, I'm not sure that the right thing was to modify the documentation.<br>> It seems that the SetRotation method actually has the bug of not setting
<br>> the translation to identity, and the SetTranslation() method has the bug<br>> of not setting the rotation to identity.<br>><br>> This should be necessary because the transform has a single TimeStamp,
<br>> and we assume that it is the same for both Translation and Rotation.<br>><br>> I'll suggest that we put the documentation back, and fix the bug in<br>> the implementation of the methods.<br>
><br>> Do you see a reason why not initialized Translation / Rotation may<br>> bring any advantage ?<br>><br>><br>> Thanks<br>><br>><br>> Luis<br>><br>><br>><br>
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