Hi fraser, generally object snaps take precedence over the grid snap.

So if you want something to snap to the grid only and avoid things like the endpoints of lines or other objects, then it is normal that you would need to turn off object snap to make that happen. The reason why object snap is able to be toggled on and off is because there are times when it can get in the way.

But if you are running into something else, could you please post the 3DM model file and maybe show me what area in it you are trying to draw on where you are not getting the results you want?

There is a mechanism that kind of combines grid snap and object snap together in certain circumstances - that's why you have both enabled and you are snapping on to a line that is running along the grid axis directions. That will enable the grid intersection points with the lines to be snappable as if they were object snap points. But that will not happen for just any curve going in all directions because it would be too time consuming to intersect every kind of curve with the grid all the time.

Is that the part that is possibly confusing you? I mean that you don't have to turn off object snap to see the grid snap when you are on axis-aligned lines?

- Michael