Hi Dick, You need to use voxel math to define an active model constraint voxel based on the geosurface.
I find it useful to get all you data into voxi and build the mesh you are going use in the inversion then export a default starting mode (probably good to use a value of 1 everywhere) as a voxel file. Then you can use this as your master voxel in voxel math. Set the region inside you geosurface to some other value (if the background is 0 I would set it to 1). set V1 (your output from VOXI) as the master voxel MV. Then use an expression something like this. Set the geosurface as SO. @var = MV == DUMMY ? DUMMY : (in(MV,S0)==1 ? 1 : DUMMY); V2 = @var == 1 ? 1 : (V1 == 1 ? 0 : DUMMY); The first line uses a temp variable @var to hold the results of an if statement. If MV is a dummy then leave as a dummy (this is cells above terrain). If not check if the voxels inside S0 are equal to 1. If so leave as 1 otherwise set as dummy. Now @var is a temp voxel with 1 inside the active area and dummy outside, but we want to put zeros in the valid parts of the model. The second expression does this. If @var is 1 then leave it as 1, else if V1 == 1 set it to 0 else DUMMY. I think this only works for closed surfaces. If you have a plane or something like that you need to do something else. Then in your voxi project set an active model constraint. Use constraint type voxel, and then choose an upper and lower bound. If 0 is not active and 1 is active in your voxel the bounds would be 0.9 lower and 1.1 upper. For padding is active I choose no. Hope this helps. Sean --- Forum archives can be accessed here: http://lyris.geosoft.com/read/?forum=geonet You are currently subscribed to geonet as: [email protected]. To subscribe or unsubscribe from any of our forums, select the User Forum selection on the Geosoft Community page: http://www.geosoft.com/support/community/forums/register/
