[Therion] vthreshold

[Xavier Pennec]

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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