[Therion] FW: Doubt about vertical sections

cawa sorix cawa.sorix at gmail.com
Fri Nov 2 17:42:01 CET 2012


Hi,

I had the same issue in my first topo, a workaround is to put 89° and
no 90°, and vertical are vertical and LRUD are LRUD.

I never really understand how use vthreshold, it will be the next
challenge maybe...

Regards,
Laurent.

2012/11/1 Marco Menchise <marco.menchise at gmail.com>:
> Thanks for the clarification.
> I admit to have missed the point, the test I made some time ago when
> starting using Therion were not enough accurate to show the vthreshold
> limit.
>
> Marco
>
>
> On Thu, Nov 1, 2012 at 9:48 AM, Bruce <bruce at tomo.co.nz> wrote:
>>
>> …so to clarify further …
>>
>> As the gradient of a survey shot increases, therion switches from the
>> assumption that passages are measured LRUD (vertical up down) to an
>> assumption that they are measured LR-front-back (up down perpendicular to
>> the passage orientation) and then at +-90 deg to the assumption that they
>> are measured NSEW.
>>
>>
>>
>> You can control the inclination at which the first change occurs by adding
>>
>>
>>
>>     vthreshold 40 degrees
>>
>>
>>
>> to your centerline block of data.
>>
>>
>>
>> Unfortunately we cannot change the NSEW behaviour (yet).
>>
>> What you need to know of course, is approach the surveyors took when they
>> were collecting the data, and adjust your input accordinly.
>>
>>
>>
>> Bruce
>>
>>
>>
>> ________________________________
>>
>> From: therion-bounces at speleo.sk [mailto:therion-bounces at speleo.sk] On
>> Behalf Of Bruce
>> Sent: Thursday, 1 November 2012 7:08 a.m.
>> To: 'List for Therion users'
>> Subject: Re: [Therion] Doubt about vertical sections
>>
>>
>>
>> Marco
>>
>> I tested your example and got the result you described with both xvi and
>> pdf outputs.
>>
>>
>>
>> I think you have found the transition defined by ‘vthreshold’.
>>
>> From the Therion Book…
>>
>>>>
>> vthreshold <number> <units> ◃ threshold for interpreting LRUD readings as
>> left-right-front-back reading perpendicular to the shot.
>>
>> If passeges are horizontal (inclination < vthreshold), LR is perpendicular
>> to the shot and UD is vertical.
>>
>> If passages are more or less vertical (inclination > vthreshold), even UD
>> becomes perpendicular to the shot – otherwise passages would not look very
>> good. In the case of vertical shots, UD is interpreted as north-south
>> dimension from the station to allow tube-like modelling of verticals
>>
>>>>
>> I had thought the default value of vthreshold was 60 degrees, but it seems
>> it may be around 67.5 degrees.
>>
>>
>>
>> Bruce
>>
>>
>>
>>
>>
>>
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>
>
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