Isometric projection is a method for visually representing three-dimensional objects in two dimensions in technical and engineering drawings. It is an axonometric projection in which the three coordinate axes appear equally foreshortened and the angle between any two of them is 120 degrees. (Wikipedia)
Isometric grid helps guiding design by its organized diagonal and vertical lines.
Isometric grid used in many drawing/design purpose or even part of a system such as game, gameplay, building design, interior and exksterior design, map, web design, etc.
Isometric grid used a game city building or farming game like City of Wonder and Farmville. Here is an example from City of Wonder (facebook game).
Also used as a movement reference in a gameplay, the character moves diagonally. The game is Pirate king by publisher Prodigy.
I made drawing by using Isometric grid as well in inkscape and that was pretty fun.
For example I made a building which is being constructed.
And one more example. An huts in the middle of a lake.
Now we get back to the main topic. Working with isometric grid in inkscape.
There are two ways to view isometric grid in inkscape.
The First Way
The first is by opening Document Properties from File Menu (Ctrl+Shift+D). Document Properties Window will appear, Choose tab Grid, click the Dropdown menu and click on Axonometric Grid.
Press New and the Grid will show up in the canvas. It comes with some set up as well, you can change the value as you need. Or dont change it at all if not necessary.
Once you done with the set up now you are ready to use the isometric grid for you drawing.
If you want to remove the grid after done with you drawing just simply press # on your keyboard.
The Second Way
The second way of viewing and isometric grid is by rendering them.
Go to Extentions > Render > Grids > Isometric Grid…
There will be a pop up window appear which shows advance setting of the grids so you can adjust it as you like or as you need.
I will just show the rendered isometric grid by default value. It is bigger than the canvas default size.
Which one better to use?
I recommended the first way to use because it is light. The Second one is good to draw detailed objects but it heavier to load, make you work slower. Sometime I got lag when using it.