Maximum Viewing Distance

[bmcdaniel]

Does anyone have any ideas or references about maximum viewing distance in various kinds of terrain?

It is likely that my PCs will be pursued by a small group of orcs across an absolutely flat, empty desert in the near future. Depending on the circumstances, the PCs may get a day or two of head-start.

The orcs will likely be making for the PCs at maximum speed without any consideration of hiding. Assuming they approach during the day, what would be the maximum distance at which my PCs could notice the orcs. Note that the PCs will be aware the orcs are after them, so they will be actively watching the terrain behind them.

I'm aware of the spotting distances on page 60 of the SMG, but the maximum distance there (720 feet) seems awfully short to me.

The more detail the better please. In particular how does different terrain alter the distance (light brush, gulleys, heavy brush, occaisional trees, etc).

Brian McDaniel

 

[Moonglum]

I'd go by book rules unless the orcs decide to set a campfire or do something else that points out their position.

 

[The Oracle]

That's 240 yards or about two full football fields including the end zones. Across a desert though, or other flat terrain, movement would indeed give away that someone was coming. Something else for you to think about is that that many creatures moving quickly will raise a dust cloud as they move, and that will be visible long before them. Erwin Rommel used to put dust dragger's on his scout cars to make it look like a huge army was on the move when it was only scout cars.

For flat but dry terrain give them a DC 25 SPOT check to notive the movement but not details at 3 times standard range. For deserts, unless the enemy is moving slowly, give the party a DC 25 SPOT check to notice the dust clouds out to 4 times standard distance. Modify to suit your tastes, YMMV.

 

[Virago]

In an absolutely flat, empty desert, you might want to do a google search for "distance to the horizon."

This site:
http://www.sundanceyachts.com/newsite/dthcalculator.html
seemed workable.

The short answer is ~3 miles to horizon -- but the orcs are going to be slightly above the horizon, so technically it's about 6 miles spotting distance. You will probably want to modify this downwards quite a bit for heat haze, and keep it at night if the other group has visible light sources.

That's what a google search suggested to me, at any rate.

 

[KarinsDad]

I created the following house rule, based on the 2E distances chart (course, it is a table and will not show up well here):

Vision: The following chart illustrates the distances at which a man sized figure could be seen. The difficulty of spotting normally ranges from DC 10 to DC 30 where DC 30 is the maximum range in column one or two and DC 10 is the range for that same thing three columns to the right, based on the distance and the conditions (the extra numbers in the first two columns are range increments). So, in clear daylight, it would be a DC 10 spot roll to detect movement at 300 feet, a DC 11 spot roll to detect movement at 510 feet, a DC 30 spot roll to detect movement at 4500, etc. It would be a DC 10 spot check to detect a stationary human in the open at 30 feet, a DC 11 at 105 feet, a DC 30 at 3000 feet.

Movement: Farthest you can see anything, only that there is movement.
Stationary: Stationary figures can be seen.
Type: General traits of figure are discernable.
Identify: Enough of figure discernable to remember/identify individuals.
Detail: Small actions can be seen clearly.
Ranges are in feet, and are maximums.

Note: Range for low light vision is doubled for Twilight and Night with the exception of Detail.

Note: The DC will be lowered for looking in the right direction, closer than the DC 10 distance, etc.

Movement Stationary Type Identify Detail
Clear day 4300, 200 3030, 150 1500 300 30
Light rain 3100, 150 1630, 80 800 100 30
Twilight 1600, 75 1030, 50 500 100 30
Light fog, snow 1300, 60 630, 30 300 100 30
Moderate fog 350, 15 230, 10 75 50 30
Night, full moon 330, 15 215, 10 100 30 15
Night, half moon 225, 10 110, 5 60 25 10
Night, no moon 115, 5 70, 3 30 15 10
Dense fog, blizzard 30 30 15 15 10

 

[bmcdaniel]

Here's what I think I am going to use:

Under IDEAL viewing circumstances, the DC to see a single Medium-size creature at long ranges is

DC 12 + (miles * 8)

or in tabular form, ...

Distance DC
============
.5 mi. 16
1 mi. 20
1.5 mi. 24
2 mi. 28
2.5 mi. 32
3 mi. 36
4 mi. 42

IDEAL means that the viewer is stationary, takes 20, there are no obstructions between him and the subject, the terrain is sufficiently uniform to show differences and the subject is sufficiently contrasty (compared to the terrain).

Here are some more modifiers to the DC:

* Each doubling of additional creatures in the subject group, -2 DC (ie 2 creatures -2; 4 creatures -4; 8 creatures -6; etc)

* Subject creatures are wearing polished metallic armor/weapons that may "flash", -6 DC

* Subject creatures are still, +5 DC

* Subject creatures are moving at half speed, +2 DC

 

[Mark]

Here's a place with a simple formula for actual viewing distance-

http://www.boatsafe.com/nauticalknowhow/distance.htm

(...and this site has a lot of useful info, simplified-

http://www.howstuffworks.com/ )

The DC modifiers for actual spotting and hiding (including those for terrain types, size, weather) are in the DMG on pg 59-60

Hope that helps!