[OpendTect_Users] Import horizons without interpolation

[Arnaud Huck]

Dear Gery,

We must distinguish two things in your observations: Visualization and 
data storage

1- Data storage: With a survey whose bin size is 25x25m, you can 
import/use any horizon whose inline/crossline spacing is a multiple of 
25m. Getting horizons with a different bin size can be done by gridding 
in the right-click menu of a loaded horizon in the tree (mainly for 
obtaining a thinner grid), or in the surface manager with the copy 
option (mainly to decimate a grid). The gridding options are also 
available in the horizon import window but the default option is to keep 
the bin size resolution of the input file.
The main new option in 4.2 is the ability to set the output bin size in 
the horizon gridding window.

2- Visualization: Here you will notice more changes in version 4.2 as 
compared to earlier versions; The old visualization was very 
restrictive, as one could see an horizon in plain only if its bin size 
was matching the survey bin size. Horizon with large stepout were 
displayed optimally as a raster, most often a very tiny lines difficult 
to see.
This restriction is now gone in OpendTect-4.2, as any regularly sampled 
horizon is triangulated on the fly when displayed in a scene into a 
plain horizon. I believe that this is what you are observing. It does 
not mean that the data on disk has changed or has been gridded, since 
the triangulation is done only for the display. The drawback is that the 
raster-like display is no longer present, but such display was not done 
in purpose anyway. I wonder how many users would need such display and 
for what purpose (in the 3D scene).
You may want to post your horizon "Z values" in a 2D viewer to see your 
real data. This is always a good QC tool if you think that the 3D 
display does not reflect your data on disk.

Best regards,
Arnaud Huck.

-- Senior Geoscientist
-- dGB Earth Sciences
-- Nijverheidstraat 11-2, 7511 JM Enschede, The Netherlands
-- mailto: arnaud.huck at dgbes.com, http://www.dgbes.com
-- Tel: +31 53 4315155 , Fax: +31 53 4315104


Le 06/09/2011 12:19, Gery . a écrit :
>
> Dear users,
>
> I'm importing some horizons (no continuous horizons) to a new OD 
> project and I noticed that they were interpolated, is it possible to 
> avoid this? I want them as they were in my former OD project (ie. no 
> continuous horizons). I'm working with the OD v4.2.0b in rhel 64-bit.
>
> Best regards,
>
> Geryfo/users
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