horizon sculpting,

[Brian Brennan]

Good afternoon all.

Couple of questions having to do with creating and viewing subvolumes:

I find it really useful for intervals that are poorly defined by continuous reflectors or that are characterized by relatively confined areas of elevated amplitude (channels, essentially) to look at a subvolume or a slab with just the higher amplitude areas opaque.  Ideally, I like to do this on a volume flattened on the nearest nearly conformable surface.  I like to look at these from the top, so I can see any patterns that look like geology. and I want to be able to move my slab up and down in the section. Is there a way to use the arrow keys to move the slab up or down?  When I orient the slab so that I can move it with the mouse I lose the perspective I want.

Another one to let me do the same thing:  Sometimes there is no nearby conformable surface.  Can I create a horizon slab by carving out a volume above and below a horizon?

Thanks for the help..

--

Brian Brennan

Geophysicist

337-258-3641

email: BrianDB...@gmail.com

website: Third Wave Geophysics.com

[Paul de Groot]

Hi Brian,

Ideally, you want to move your slab through a completely flattened cube. This is possible if you flatten the data with a HorizonCube (SSIS plugin option). In the Wheeler scene you can then use the volume viewer feature described below. 

If you do not have a HorizonCube, you can add a scene that is flattened on one horizon only. In this flattened scene, you can add a volume viewer. As you rightly say, this only works for a stratigraphy that is conformable to the horizon that is used to flatten the data.

Moving a slab up and down is possible with the volume viewer. You need to load data in the volume (use the Position option) and resize the viewer to the slab dimension. Next use Shift -Left click and drag to move the slab up and down. An example of this  feature showing a color-blended volume viewer is shown in this LinkedIn post. 

Can I create a horizon slab by carving out a volume above and below a horizon?

Yes, you can but you cannot move such a slab through the data. You would have to compute a slice of data with an attribute set that sets all values above the top horizon and all values below the base horizon to undefined. You then use a colorbar that displays undefined values 100% transparent. The attribute set you need to construct comprises three attributes:

topZ = Horizon attribute -> output Z of top horizon

baseZ = Horizon attribute -> output Z of base horizon

mathematics attribute with equation: (Z > topZ) && (Z < baseZ) ? Output : Undef 

Note that in the Wheeler scene this is a non-issue as everything above and below your slab is not displayed.

Best regards,

Paul.

--

Paul de Groot

Geoscience Manager

-----------------------------------------------------------------------------------------------------------------------   dGB Earth Sciences
Phone: +31 53 4315155 E-mail: paul.d...@dgbes.com Internet: dgbes.com

----------------------------------------------------------------------------------------------------------------------- 

--
You received this message because you are subscribed to the Google Groups "OpendTect Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to users+un...@opendtect.org.
To view this discussion on the web visit https://groups.google.com/a/opendtect.org/d/msgid/users/CAEmE0gsKJ2mUVcoQ6-3bx8q5emKq5-_mirYi5eUgysxFKnLirA%40mail.gmail.com.