[Users] *New features* Implicit representation

[Arnaud Huck]

Dear users,

OpendTect features now the possibility to create an arbitrary shape from 
a volume containing numbers. This is a function most often called 
implicit representation. The shapes (iso-surfaces) may be very complex 
will multiple Z values for each position, to allow the definition of a 
complex salt structure for instance.

Iso-surfaces are generated with the volume viewer by adding an element 
of type "Iso surface": Right-click on the main volume element --> Add 
--> Iso surface. The iso surface will be created at the mid value of the 
colorbar range. Therefore it is recommended to first adjust the colorbar 
range before adding the iso surface element. We also strongly recommend 
to switch off the planes and volren element of the volume viewer when 
creating/using the iso surface element.

For instance in order to view a salt structure from an interval velocity 
volume you could set to colorbar to range from 1500 to 7600 (m/s), such 
as the average is 4550, the expected salt velocity that should provide 
the best display. A second example would be to set the colorbar range 
from 0 to 2 in order to visualize the structure highlighted by an object 
probability volume (FaultCube, SaltCube, ChimneyCube, ...) using the 
implicit representation. Indeed the high probabilities will be around 
the value 1 in such a volume.

The creation of an iso surface is always very time consuming as it 
requests a lot of CPU processing. In the right-click menu of the iso 
surface element you will find a utility to correct the iso surface value 
based on the displayed histogram. Once the right value is found you 
might convert your iso surface as a body since stored bodies do not any 
more request a computation. Please note that only the data loaded within 
the volume viewer will be converted into an iso surface.

Bodies may then be saved using a relevant name and some properties are 
available to fine tune their display. Since created bodies cannot be 
edited, the input volume loaded into the volume viewer could be an 
optimized volume filtered using attributes, prior to its conversion into 
a body.


Best regards,
Arnaud Huck.

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