Using line of sight in Maptool (Part 2)
by, 05-09-2011 at 06:44 AM (11962 Views)
Last time I promised that MapTool would hide and reveal enemies and sections of the map as the players moved around. Then I showed you how to get MapTool to draw white lines representing the vision. Which is just a tad short of the promise I made.
So lets play with more settings and see if we can't make that happen then. Choose Preferences from the Edit menu, go to the Application tab and look for the check box "Auto-expose fog on token movement" and be sure its checked. That setting will need to be made by yourself and each of your players. Next lets go to the menu, choose Map -> Vision -> Day and it should now show a check box next to that option. Then choose Map -> Fog-Of-War to check that setting too.
What this accomplishes is having MapTool hide tokens and draw a fog over areas that the character can't see. Making it far more clear to the players what is truly within their line of sight. When you're conencted to the game as a GM everything will be revealed to you, whereas from a player perspective if something doesn't fall within a player character's line of sight it won't be revealed. Have a look at this, here's how the GM would view the map:
He sees four tokens. The two on the left are the PC tokens that have vision, the two on the right are the NPC tokens without vision. The shaded area represents parts of the map that aren't within line of sight. Notice how that area entirely covers the blue wolf token and part of the red troll token. Because of that here's what the players see:
The palyers can see anything that falls within line of sight range. Because of that the wolf doesn't at all appear on their map, and the troll is partially concealed.
When you're working with the maps it might be worthwhile to flip between these vies by choosing View -> View as Player. That will change the map so that it shows the map exactly as the players would see it.
This is probably not ideal. Just because one player can see something, doesn't necessarily mean the rest of the players can see it. MapTools realizes this, and will tweak the map so that it only shows what that particular character can see. To do so, all you need to is select on of the tokens with vision, and voila! The map shades out what can't be seen, and even removes the tokens that are now out of sight. Here's that same map as seen from each of the PC characters:
You can enforce the vision limitations on the players when you start up a server. Just check the following settings: Strict token ownership, Players can reveal vision, and Use individual views.
Then when the players connect be sure that they have ownership of their respective tokens. If they don't have the onwership the map will stay entirely black.
It can certainly add to the immersion when the players can only see portions of the map. It will definitly make your surprise attacks much more interesting. Though I should mention that there are a few warnings that you should take into consideration when making use of these features in maptool.
- Be sure the players are aware that they can't see everything. Vision isn't revealed while the token is being dragged, only when its released. So if you have some monsters flanking a doorway waiting to pounce on any PC that enters they might run straight into the room unaware, while you're cutting them to ribbons with attacks of opportunity. In reality the character would have approached the door and possible see the monsters, before going through. If not the PC definitely would have stopped when the blades struck them. To counter this I suggest the players stop their movements at all doorways and corners to let the map update, then continue their movement.
- It is possible for the line of sight calculations to get a little CPU intensive. This doesn't happen often, but one of my players has a slower machine, and was exploring an extensive cavern. Because there wasn't straight walls I made heavy use of the polygon tool to set my vision blocking layer. Drawing that way puts the heaviest load on the CPU when figuring out whats in sight. If you can stick to the rectangle and circles since they are much easier. Keep in mind that the vision blocking stuff isn't visible to the players, so it doesn't need to be perfect. Having the edges sloppy and not quite in line with where the background images show the walls won't detract from its effect. Its not likely that this will be a problem, but I figured I'd mention it anyway.
- If you use the fog of war on your maps, which indeed I suggested, it will not remove the fog where the vision blocking layer is. Which means that part of the artwork won't be revealed to the players. With the map that I made here's how the fog would effect it:
The players can see there's an obstacle there, but with just that black square they've no idea what it is. For rocks and walls thats probably ok, but if you had a door there or something else they might want to interact with it might be a problem.
- The map is only updated when a token moves. If you do have a vision blocking layer over a door, and when the players opene the door you then erase that bit of vision blocking, the players won't immediately be able to see whats beyond. Once a token with sight moves on the map it will update with what has newly been made visible. Its a little clunky, but its probably better than having it perpetually running those calculations.