Le 15/05/2012 23:54, Andrew Atkinson a écrit :
On 15/05/12 21:37, Bruce wrote:
I also do as Xavier describes, and agree that compass bearing (even if clino is vertical) seems to be the logical way to orient LRUD. Bruce
Orientating to the passage has always been most logical to me, but I do see that the above is very valid. However what do you do on a true vertical, as it does not have a compass bearing?
For a true vertical, you can provide the bearing of the UP width. Most often, if it is not measured, I take by continuity the bearing of the previous or the next shot (this provides a much better 3D model than NSEW). If you whant to use NSEW, you can put 0 (UP=N). Whatever bearing you provide in the measurements will not influence the shot itself anyway. Xavier
-----Original Message----- I completely agree with you that NSEW is not not a good way to measure the shape of about-vertical passages. In fact I personally never measure dimensions in NSEW directions but in the direction of the shot (or of the preceeding shot if it is absolutely vertical), in the reverse direction, on its right and on its left. I use LRUD with Up meaning in the (horizontal direction of the shot and Down the opposite.
As we have to give a bearing anyway for vertical shots, why not use it to orient the dimensions instead of a vthreshold-offset that should be changed for each new shot?
Xavier
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------------------------- Xavier Pennec Senior Research Scientist / Directeur de recherche Asclepios project-team, INRIA Sophia-Antipolis 2004 Route des Lucioles, BP93 F-06902 Sophia-Antipolis Cedex, France +33 4 92 38 76 64 +33 6 78 35 16 90 http://www-sop.inria.fr/asclepios/ -------------------------------