Coding Blocks that Intersect with Surfaces

Writing codes to block models is a common operation when working with geological data. You might want to assign a series of codes that relate to the ore zones, vein solids, pit shells, resource domains, and more. The existing tools make it simple to code blocks that are Above, Below, Inside, and Outside of DTMs/Grids/Wireframes. 

What do you do if you want to simply code a value to blocks that intersect with a surface? This is a nice way to include block model data in figures without overloading them with visual obstructions.

In our example below, we have a block model that was generated by Grade Copilot and some topography. I want to display only the top levels of this block model. 

We're going to use one of the functions in the Grid / DTM | DTM Assign | Assign Block Model tool to do this. 

Here's our setup for the DTM Assign forms. The Input/Output panel is simple. Have your block model and topography surface chosen, then check the box to Overwrite the input file. 

The Block Model panel is where the magic happens. We're going to use the Block Factor field to tell us which blocks only partially intersect with the topography surface. In this case, blocks that are completely above the topography have a value of 1. Blocks that are completely below topography have a value of 0 (zero). Blocks that intersect with the topography will have a value between 0 and 1 which represents the percentage of the block that is on either side of the topography.

Once you've run the DTM Assign function, we can build a block model filter to limit our display. We know that our intersecting blocks have a value between 0 and 1. We can build a simple 1-line filter that shows us only blocks with a value greater than 0:

After applying my filter, this is the result. The top level of my block model is cleanly visible and follows the topography surface. You could apply this function to fault planes, pit shells, and whatever else you wish to see with its directly related blocks. 

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