Raise my map fu -- drawing light sources on a battle mat.

[Noumenon]

I sure hope Chris Perkins has more map fu tips to give because my battle mats have gotten a lot cooler with cliffs and such. Now, how do I represent shadowy illumination on a battle mat, say a temple where the torches give bright light everywhere except behind the altar? Should I use movable templates since I will need them to adjudicate PC's torchlight anyway?

Edit: Another example is a tower with a lit spiral staircase that leads into a dark room at the top. You'll have shadowy illumination for just a few squares around the top of the staircase. I have a PC aiming toward Shadowdancer, so I want to get the darkness right.

 

[howandwhy99]

Start easy and "cheat" to keep it that way.

Mobile light sources can be marked like tokens under minis, if you really want. Then let the players know those are 20' (4 squares) or 30' or whatever they are. When they move that's all the farther you're going to be drawing out on a battlemat anyways.

Relatively static light sources are set up to illuminate everywhere so creatures can see. Noting shadowy spaces can be done on the DM map behind the screen. These are gonna to be behind cover anyways, right? So until the shadows comes into line of sight, just leave them unmarked like whatever else is behind cover. Then dash mark it if a battle breaks out, and use a distinguishing color if possible. Just telling the players is usually enough otherwise.

"Cheating" means not having to draw this stuff in the first place. Your player's lamps and eternal flames are going to give off quite a glare anyways, so it may not be such a big deal to build all this stuff.

However, if you really do want to help sneaky types, then build in some areas where shadowy illumination is hard to avoid (like lots of columns in a room, half walls, curtains, a single corner brazier, etc.) Players should be taking initiative anyways to putting out lights and creating their own shadows whenever desired anyways. It's in their best interest. Note this stuff for affecting the difficulty of the challenge too though. Shadows make places easier to sneak into. This is why guards use lights (while not always standing in them).

 

[ShadowAssassin]

What I've done is use thin transparent sheets of OHP film in pale yellow. Cut to size to represent the glow from a torch or lantern (5"x5") and slide it under the mini et voila!

 

[Janx]

What I've done is use thin transparent sheets of OHP film in pale yellow. Cut to size to represent the glow from a torch or lantern (5"x5") and slide it under the mini et voila!

Welcome to the forums!


I'm just making this up as I think about it:

Let's say you used black marker for all the walls, furniture, columns, etc.

use a red or yellow marker to put a small circle/ big dot where the light source is.

let say there's a fire pit/brazier in the center of a room lined with columns (it's a longish hall, with columns on the left and right)

Take a ruler and place the end from the center of the light source and the other end on the edge of a column. trace a line (dotted?) from that column outward (the line goes from the column and away from the light source)
repeat for the other edge of the column.

What you have is the shadow space behind the column.

Repeat this per column (or any other significant object in the room with space behind it).

you could stipple the area with dots to show it is "darkened"

 

[Stormonu]

Get a sheet of black construction paper. The larger, the better. Cut out a hole the size of illumination, and place it down with the light source at the center. The black area now obscures what can't be seen.

 

[Janx]

Get a sheet of black construction paper. The larger, the better. Cut out a hole the size of illumination, and place it down with the light source at the center. The black area now obscures what can't be seen.

that covers fog of war, but kind of misses the determination of shadows behind objects.

In simplistic terms, light casts out from the center in all directions.

You can determine the area that remains dark due to an intervening body, by projecting those lines from the center of the light source as it intersects the edges of that body.

Thus, the band of shadow is narrowed near the body (a pillar), but widens the farther back from that pillar.

Assuming the light source is coming from a relatively low source, ( a wall sconce, fire pit), then the shadow will be long enough to reach/cover the wall.

If the light source is high, that's where the shadow is really just an elongated outline of the body.

 

[gamerprinter]

When I need to really accurate in a map with 3D lighting, I actually create the base structures of the map in 3D and illuminate using the lights within a 3D program, but this I only rarely do.

Usually, I create the entire map as if it were completely illuminated. Then I place a 50% more or less transparent black, gray or dark blue layer of shadow over the entire map. Whereever a light source: moon/sunlight through a window, a lantern on a table, a lit fireplace, I cut out the shadow areas to reveal the illuminated areas beneath.

Having worked with 3D lighting within 3D software gives me good insight into what realistic 3D shadow and light should appear.

Of course I use Xara Xtreme to do my map creations. Doing so in Photoshop is trickier - so you'll probably need somebody more familiar with Phtoshop to give the tips you need.

 

[Chris Knapp]

Welcome to the forums!


I'm just making this up as I think about it:

Let's say you used black marker for all the walls, furniture, columns, etc.

use a red or yellow marker to put a small circle/ big dot where the light source is.

let say there's a fire pit/brazier in the center of a room lined with columns (it's a longish hall, with columns on the left and right)

Take a ruler and place the end from the center of the light source and the other end on the edge of a column. trace a line (dotted?) from that column outward (the line goes from the column and away from the light source)
repeat for the other edge of the column.

What you have is the shadow space behind the column.

Repeat this per column (or any other significant object in the room with space behind it).

you could stipple the area with dots to show it is "darkened"

We do pillars (and other single square blocking terrain) a bit differently. Assuming the room isn't completely light absorbent, we just say the single square opposite the light source is in shadow. This makes tracking moving light sources much easier.

 

[Stormonu]

that covers fog of war, but kind of misses the determination of shadows behind objects.

In simplistic terms, light casts out from the center in all directions.

You can determine the area that remains dark due to an intervening body, by projecting those lines from the center of the light source as it intersects the edges of that body.

Thus, the band of shadow is narrowed near the body (a pillar), but widens the farther back from that pillar.

Assuming the light source is coming from a relatively low source, ( a wall sconce, fire pit), then the shadow will be long enough to reach/cover the wall.

If the light source is high, that's where the shadow is really just an elongated outline of the body.

That could be simulated with (widening) strips of black construction paper, if you want the additional detail.

Redrawing light sources every time a Pc moves would not be how I want to spend my gaming time.

Also, the construction paper might work better on maps you don't want to mark up (say, their not laminated or are Dungeon tiles).

 

[Janx]

That could be simulated with (widening) strips of black construction paper, if you want the additional detail.

Redrawing light sources every time a Pc moves would not be how I want to spend my gaming time.

Also, the construction paper might work better on maps you don't want to mark up (say, their not laminated or are Dungeon tiles).

so Shadow Wedges of a sort?

Bear in mind, I'm talking about drawing the shadows for static light sources. Akin to what the original Map Fu article was about, which was simple art tricks to use on your battlemat that look artistic but are actually simple.

On [MENTION=65116]Chris Knapp[/MENTION]'s method, that works for high-up light sources which cause shadows to be shorted.

For low/nearly parallel light sources, the shadows are elongated enough to mostly stretch to the room's borders. A decent metric for this effect is that shadows are "infinite" length if the light source is not higher than the blocking object.

Thus, a pillar going to the roof is always casting an infinite shadow from a light source in the room.

Whereas, the shadow from a chest that stands 2' tall is probably not infinite and could be abstracted to be 1-3 times long its actual height for most elevated light sources in a room.

Also, the more light sources there are, and the more seperation from them should reduce the effect of shadows as rays from other light sources spread over a single light source's shadow zones.

I'm just giving rules of thumb and not actual science. It's a complicated problem video games have to solve and there is math that can calculate the length and size of a shadow based on the size of the intervening object distance from light source, light source position (and height) and intensity of light.

Extending Chris's algorthm, trace a line from the light source to the column. Anything behind that colunn (not just single square) is in shadow.