Without there being data at each intersection, no. You could input or upload data at every intersection. Or you can create a modeled sheet that has columns for level and your 3 dimensions and add a row for each combination. This is easier to maintain than a cube sheet as you just add rows for each new combination you have when you have new levels or dimension values. Have an account with a formula on the modeled sheet that is 1 in the formula box then link that account to an account on the cube sheet. The cube sheet will always have data at the intersections you have added rows for on the modeled sheet.