How to edit (given) grade shells or other surfaces?
In many projects grade shells or other geological structures are modelled by external parties, mostly consultants. This means that unless you have the same software and the actual project they used to create the shells or surfaces you either need to complete redo what they did or find another way to update those files. In this article we highlight some effective tools that allow you to quickly make adjustments without needing to redo all work.
To adjust strings we Edit the contours object we created from the original grade shell and step through the individual strings to the point where we want to make some adjustments. Of course, you can edit multiple strings this way. Once you are happy with your edits, use the newly saved polyline to re-create the implicit surface.
Planar structures like bedding planes or faultsIf the project you work on has some planar structures that were created externally, there is an easier way to quickly edit a surface. Using the Edit Surface tool you can directly pull / push a surface to make local or global changes.
To use this tool effectively first select the surface to adjust. Then decide if you wish to move the entire surface or make a local change. In this example we show how you can make local changes to prevent cross-cutting hanging wall and footwall surfaces for a vein. As you can see below a local area shows where the hanging and footwall surfaces intersect and will produce a hole if used to create a vein. This usually occurs where insufficient data is present. We can choose to move each side a bit, but for demonstration purposes we will just modify to Top surface. When selected, the triangles edges will show with their node points. Click on a node point to move the surface in the direction of their thickness (or the opposite). The radius setting determines how great the radius of influence is on neighboring nodes of the clicked node. For local adjustments the radius should be relatively small.
Of course this technique can also be applied if you do think there should be a pinch-out somewhere. In that case do exactly the opposite, by moving the plane to create the cross-cutting.