[Users] get ride of 1e30 values

[Geert de Bruin]

Dear Laurent,

First of all you can make the Undefined color transparant by doing  
the following:
- Select your Volren volume in the tree, then right click on the  
color-bar and select Edit..
- In the 'Colortable Editor' click on the Undefined color
- Now set the alpha channel to 255 to make it transparent.
http://www2.opendtect.org/rel/html/x131.htm#LINK-COLOR.EDIT

Note 1: In 3.0, for the first time, OpendTect can use 'shading' to  
improve graphical performance. This means that some calculations are  
done on the graphics card rather than on the CPU.

We found that many graphics cards are capable of shading nowadays.  
Rather old cards do not support it and report this to OpendTect which  
then won't even try to use it. Good new cards (like the nVidia 6000  
series) report they support it and actually support it well. The snag  
is that some cards of about 1-2 years old do give problems. These  
report that they support shading, but they support only part or they  
support it so badly that the system almost stops. In particular  
shading for volume rendering gives more problems than 'ordinary'  
shading. Then try visiting the menu 'Utilities-Settings-Look&Feel'  
and disable the shading altogether (consider buying a new graphics  
card though).

Note 2: For older OpendTect versions (v2.4) we have noticed a problem  
with transparencies when we restore a session.

What happens is that the displayed element (inline,crossline,  
timeslice, etc ..) can disappear from the display, or there is no  
display when we move the mouse into the scene. It can also happen  
when clicking for instance on the view mode, or when trying to  
restore an other saved session.

This is a characteristic of a bug in nVidia OpenGL drivers. Our  
developers have just updated to the latest nVidia driver and the  
problem is probably solved.
Thus to get rid of that, update your nVidia card or do the following:

- Right click on the colorbar
- Choose 'Edit'
- Click on the 'Undefined color'
- Change the 'Alpha channel' value from 255 to 254.

Best regards,

Geert


On Jul 10, 2007, at 1:02 PM, <Laurent.Langhi at csiro.au> wrote:

> Dear users,
>
> Is it possible not to display the 1e30 values? (or eg assign them a  
> value in order to make them transparent)
>
>
>
> In a large survey I have imported a sub seismic volume which is not  
> regular and which has seismic data between two dipping surfaces. So  
> also the cube itself is delimited by inlines and crosslines and  
> time slices, the data only represent a part of the volume, the  
> remainder is 0 value read as undefined values (1e30) in OD.
>
> When I display in Volume-Volren a meta attribute computed on the  
> sub seismic volume I have my attribute cube “surrounded” by 1e30  
> values coloured in green which complicate the visualisation.
>
> Is it a way to get ride of these undefined values in the display  
> mode? Or a way to define a sub cube following other directions than  
> inlines and crosslines? (so then lateral extent of the sub seismic  
> volume will include only real seismic data)
>
>
>
> Many thanks
>
>
>
> Laurent
>
>
>
>
>
> Dr Laurent LANGHI
>
>
>
> CSIRO Petroleum
>
> Australian Resources Research Centre (ARRC)
>
> Technology Park, 26 Dick Perry Ave, Kensington  WA  6151, Australia
>
> Tel:      +61 (0)8 6436 8741       Fax:  +61 (0)8 6436 8555
>
> Email: Laurent.Langhi at csiro.au
>
> http://www.petroleum.csiro.au/
>
>
>
>
>
> _______________________________________________
> Users mailing list
> Users at opendtect.org
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-- Geert de Bruin
-- Geoscientist
-- dGB Earth Sciences B.V.
-- Nijverheidstraat 11-2
-- 7511 JM Enschede, The Netherlands
-- geert.debruin at dgb-group.com
-- http://www.dgb-group.com
-- Tel: +31 534315155 , Fax: +31 534315104




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