Fast Road/Slow Road

[Boco]

Back in August of 2000, William Keenan posted this gem of a discovery:

You can get some strange, but predictable, results by using very high movement points. This is due to the way computers do math and how it handles numbers larger than the field was designed to hold. If you set the movement rate of a unit to 171 in the RULES.TXT the result is that the unit has a movement allowance of 1/3 point. Every point of movement you add gives the unit and addition one movement allowance. Therefore, a movement rate of 172 creates a unit that can move 1 1/3.A movement rate of 342 creates a unit that can move 2/ 3. It follows that a movement rate of 343 creates a unit that can move 1 2/3.These numbers assume that the road movement multiple in the @COSMIC is set to three

What may not be widely known, is that it can also apply to the movecost of a terrain. The following example is also posted on a thread on Apolyton*, but much of the time, I'm too impatient to wait on that server.

To make a 'slow road' terrain, I had set the movecost to 205 (Road bonus =25, set to >10 to take advantage of WK's fractional movement math). Civ2 behaves oddly but reproducibly with these settings. Regular roads (and rivers) cost 1/10 mf; the new 'slow road' costs 2/10mf.

There's a kicker: the Civ2 terrain editor squawks when it encounters an out-of-range variable. I was tweaking the 'slow road' terrain image via the Editor menu in Civ2, when it spotted the movecost was set out of range. It did me the 'favor' of resetting the movecost to 0 in the rules.txt.

*Currently there's a thread there (by FMK) looking at using WK's math on things like production costs.

 

[Case]

Originally posted by Boco
To make a 'slow road' terrain, I had set the movecost to 205 (Road bonus =25, set to >10 to take advantage of WK's fractional movement math). Civ2 behaves oddly but reproducibly with these settings. Regular roads (and rivers) cost 1/10 mf; the new 'slow road' costs 2/10mf.

Would It be possible to make a 'fast road' using the same method? If so, then you could create roads which have a low movement cost and could be used to simulate railroads (eg via placing a 'rail base' terrain under the road)

 

[kobayashi]

The fractional movement allowance has been around for a while and a prime example of its use is Bebro's ImpRom scenario. That was implemented transparently but if both terrain and units start ot have fractional movement values that would be too much. I tend to think that anything that confuses the player further should be avoided unless it serves a specific purpose.

For instance, you could theoretically have a slow road/fast road implemented by making all the terrain except one have high move costs (i.e. all like mountain) and give all the units high movement allowance.

 

[Henrik]

Originally posted by Case


Would It be possible to make a 'fast road' using the same method? If so, then you could create roads which have a low movement cost and could be used to simulate railroads (eg via placing a 'rail base' terrain under the road)

Yup, you can even have a terrain with movecost 0 (railroadish) however unlike normal railroad this terrain wont cost you movement to "step unto" either.

I discovered this myself about 6 months ago when working on an upgrade for Exiles Modern Age scenario (I did ofcourse have the authors permission, etc) for the mountain passes (not sure if it made it into the final version though).

 

[kobayashi]

Originally posted by Henrik


Yup, you can even have a terrain with movecost 0 (railroadish) however unlike normal railroad this terrain wont cost you movement to "step unto" either.

This also manifests itself as the wormhole in Dominion War.

 

[Boco]

Kobayashi wrote,

For instance, you could theoretically have a slow road/fast road implemented by making all the terrain except one have high move costs (i.e. all like mountain) and give all the units high movement allowance.

One thing to take into account with this alternative approach is that land units designed to move more than one square off road will have relatively high mf's (e.g. >6). If such a unit is adjacent to an enemy at the start, it has the opportunity to attack multiple times or attack and withdraw to a safe position. Uncompensated, this can shift the balance in favor of offense, which could be either beneficial or detrimental depending on the scenario.

Case, WK's math has limited solutions in practice. If the road bonus is 5, and the movecost is 205, then the terrain has the same cost as a road/river (1/5). You're right, I was motivated to find a pillage-proof road. In Red October, Techumseh is using a nifty trick with 'rail bed' terrain and train units, but it requires ToT (yet another reason to create scens with ToT).

I think all of these solutions suffer from the 'no cost to go from offroad to onroad' characteristic that Henrik mentioned. Any wizard know a way around that?

Thanks for the insights.