Mostly out of curiosity, do you have any insight into how this will be addressed in the new guidelines? Even if it's just a little more guidance on when it's appropriate to use mat/layering methods and when it's appropriate to use 3D cubes, that would be very helpful.
The BANA guidelines for tactile graphics are currently in the final approval phase. We don't have special knowledge of their contents. BANA, NBA, and other organizations will actively announce those revised guidelines when they are available.
In the meantime, we can share the following:
The NBA training materials for TGs include the following examples as appropriate for the mat plan method. (Note that these examples from NBA training materials use pre-UEB braille.)
The attached figure 1 shows print graphics that would be rendered as mat plan tactiles.
The attached figure 2 displays how one would use the mat plan in a tactile image of the graphic shown.
The attached figure 3 shows a block figure that should be produced as a tactile using the layering method. The layering method is used in this case because there is empty space under cubes in the top layer.
The attached figure 4 shows how the layering method would be used to produce a tactile graphic of the block object shown in figure 3. Notice how shading is used to signify the blocks, and no shading is used to signify where there are no blocks in each layer.
We hope this answers all of your questions for now!