When Covid led to widespread lockdowns, our D&D group, like so many others, switched to playing virtually. A lot of virtual gaming can be done via Zoom (or whatever your preferred technology is) as a theatre-of-the-mind thing. But it often helps to use a virtual tabletop (VTT).
There are quite a few VTT's out there, but our group uses Roll20, mainly because it's established, has a relatively easy learning curve, and doesn't require an instant subscription from all players.
Finding battlemaps to import into a VTT is easy; Google images is full of them. Admittedly copyright can be a grey area in some cases, but there are plenty of patreons offering quality maps for low prices, often with free samples.
Battlemaps have to fit the grid - or do they ?
When I first started using Roll20, I struggled repeatedly to get the grid on imported battlemaps to match the grid within the VTT. I wasn't the only one; we have a system of "rolling DM's" in our group, where we take it in turns to run adventures, as a way to help avoid burnout and "Eternal DM" syndrome, and most of the others had exactly the same problem.
But the reality is that the grid is already available in the system, and I rapidly realised that it was far easier to import a map without any kind of grid and then just resize it so the distances were about right (particularly things like corridor widths). In most cases, we've found that having grid squares exactly aligned with walls etc really doesn't matter. I tend to line up a couple of key points on the map, and during play common sense tends to work just fine with very few occasions where the DM has to step in and say "oh, you can't go there".
Does the map have to be top-down ?
While I was surfing the net a while back, I came across a really sweet tool - FlowScape. It's on both Steam and itch.io (although I understand itch.io passes more of the revenue onto the authors than Steam). It's not a free package, but only costs $10 - you can find it at https://pixelforest.itch.io/flowscape
It's a 3D modelling package designed for artists and game designers. You basically create a landscape, populate it with plants, buildings, weather effects and can then either take a short video clip (which I haven't worked out how to do yet), or you can move the camera angle around until you get a view you like and take a snapshot.
Being honest, I haven't mastered FlowScape by any means. It's a complex package with lots of tools and toys to play with, and it's easy to get unexpected results. But even just playing I've managed to make some useful stuff. What I love is that you can use the tools it gives you to generate a top-down map, or take a snapshot from any angle. I found the top-down maps great for gameplay, but the reality is that a high-level angle works just as well, and is visually far more appealing, giving a real impression of perspective.
Even better is that taking a low-angle snapshot gives you a fabulous tool to show the players a "this is what you see" view. To give you an idea, the party recently had to fight their way through a snow-covered river valley. The image at the top of this post is what I initially showed them to create an impression of the landscape. By using the high-level snapshot below, I was then able to use the exact same terrain as a battlemap. It worked really well, although I'm not sure if the players appreciated it so much when the Frost Giants emerged from the treeline chucking boulders at them.
Other uses for perspective battlemaps
I've found a few other uses for perspective battlemaps. The key thing really is for players to be able to rapidly realise which parts are the playable area, and which parts are just decorative. For example, below is one I did for the fighting arena of Faden the Black in the slums of Milmar, with the snapshot taken from a very high angle. Only the arena itself was playable, the rest was just to add flavour.
But again, I was able to take a ground-level snap to give a real flavour of the place;
I also found that using an historical visualisation of Roman Barcelona (not posted here, because although it comes from a free app I don't want to risk treading on copyright toes) was a great way to run a town adventure. It really didn't matter that it was a relatively skewed perspective; as long as the players could clearly indicate which buildings they were visiting, it worked brilliantly for gameplay and was far more visually appealing that a dry top-down map.
So I definitely suggest thinking out of the box when it comes to backgrounds for gaming with virtual tabletops. If things are reasonably clear to the players and it adds atmosphere to the game, go for it !
P.S. I know I've raved about FlowScape in this post - they haven't sponsored me or anything, it's just one of my favourite tools :)