It would be great if individual triangles could be selected.
Alternatively, there could be an option that with a lasso or rectangle the whole triangle is selected even if there is only one vertex included in the selection area.
Standard Autocad behaviour is: Click/hold>Drag a rectangle from R to L>Release - the whole of whatever elements are even partly touched/enclosed, are included (alternatively Click>Drag a rectangle from R to L>Click again to confirm).
Same but from L to R - only elements fully enclosed by the rectangle are selected.
Having selected one lot, hold Ctrl down and add to the selection set.
Hold Shift down and it deselects (trims away) part of what you’ve selected.
In addition, click directly on any element and it selects the whole of it - whether it’s a line, a perimeter/edge, a surface face, or a solid.
Allows multi-pass precision selection/deselection until you get it just right. It’s very fast, muscle-memory useful. Makes hard-to-be-precise lasso unnecessary.