The isometric grid itself is basically the guideline to have the right angles when drawing from an isometric perspective.
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The “true isometric grid” has a 30º angle between the x and z axes to the plane. Graphic design software like Vectornator offers the feature to easily edit the angle of the isometric grid. Also, you are able to increase & decrease the size of the grid which is super helpful if you want to add for example a small balcony on your isometric housing.