The ruler tool would work in the cardinal directions, but not on diagonals. For this reason it helps to have the isometric "grid" on your map art because you can count squares to determine diagonal distances. What other tools are not available? Here are some informative and useful posts about Isometric maps in Roll20 and how to work with the grid options: Read the tips and Notes by Brian here first: (I recommend copying down this information, or save as a Handout in your game to reference later when making your maps) <a href="https://app.roll20.net/forum/post/1571397/maps-rot" rel="nofollow">https://app.roll20.net/forum/post/1571397/maps-rot</a>... Here is a transparent grid (can be used as a background graphic or map overlay), <a href="https://app.roll20.net/forum/post/1261/isometric-g" rel="nofollow">https://app.roll20.net/forum/post/1261/isometric-g</a>... David's work with fitting Iso grid using Roll20 grid in a way, <a href="https://app.roll20.net/forum/post/345968/isometric" rel="nofollow">https://app.roll20.net/forum/post/345968/isometric</a>... Plexsoup demonstrations of his isometric tile use in Roll20, NOTE: he turns the grid OFF, <a href="https://www.youtube.com/watch?v=hxqFQChjAjs" rel="nofollow">https://www.youtube.com/watch?v=hxqFQChjAjs</a> There are also some Suggestions on the Suggestions & Ideas board, for this kind of grid and Ruler measurement on the diagonals. Search for isometric under Suggestions if you can lend comments or a vote.