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Dwarf Fortress => DF Dwarf Mode Discussion => Topic started by: zzedar on April 11, 2013, 02:32:19 pm

Title: Open room calculations
Post by: zzedar on April 11, 2013, 02:32:19 pm

So I just recently discovered something interesting about how room value is calculated -- specifically, how openings in the walls affect it. Here's the math. Please note that I'm only confident about this for rectangular rooms -- I haven't tested it out for other shapes.

Let v_r be the value of the room itself, including the the value of the building used to designate it, and the value of the walls and floor (including material modifiers, smoothing/engraving, etc. -- see Kipi's excellent work (http://dffd.wimbli.com/file.php?id=7326) for how to calculate this).

Let v_f be the value of any additional furniture installed in the room (not including the item used to designate the room in the first place).

Let n_b be the number of border tiles the room has.

Let n_e be the number of those border tiles that are "empty" -- i.e., not occupied by a wall or door. (Note: I'm not totally confident that doors count as non-empty, but I think they do).

Let V be the total computed value of the room.

Then:

V = (8 - ceiling(4*n_e/n_b))*v_r/8 + v_f

Or to put it more simply:

V = mv_r + v_f

where m is given by the following:

No gaps	m = 1
Up to a quarter of the border is gaps	m = 7/8
Up to half of the border is gaps	m = 3/4
Up to three quarters of the border is gaps	m = 5/8
More than three quarters of the border is gaps	m = 1/2

I have not tested to see what effect overlapping rooms have on this, nor am I certain whether doors count as part of v_r or part of v_f.

Edited for readability

Title: Re: Open room calculations
Post by: krenshala on April 11, 2013, 03:01:46 pm

Can't you determine which value the door applies to by changing what door is installed in a particular doorway?  No door versus door versus +door+, etc.

Title: Re: Open room calculations
Post by: zzedar on April 11, 2013, 03:25:33 pm

Yeah, I plan to test that out, I just haven't gotten to it yet.

One interesting consequence of this is that if a room is going to have a lot of openings, it may be best to designate the room from the least valuable item of furniture in it.

Title: Re: Open room calculations
Post by: i2amroy on April 11, 2013, 04:58:27 pm

Quote from: zzedar on April 11, 2013, 02:32:19 pm

I have not tested to see what effect overlapping rooms have on this

Overlapping floor rooms provide a flat *(1/4) onto any room's value. As for overlapping wall tiles, I'm not sure if that has any effects.

Title: Re: Open room calculations
Post by: Laserhead on April 11, 2013, 09:55:12 pm

I'm pretty sure doors are counted. Many of the doors in my fort are high quality gold doors, and they seem to improve the value of a room compared to stone doors.

Title: Re: Open room calculations
Post by: celem on April 11, 2013, 10:01:43 pm

Quote from: Laserhead on April 11, 2013, 09:55:12 pm

I'm pretty sure doors are counted. Many of the doors in my fort are high quality gold doors, and they seem to improve the value of a room compared to stone doors.

The question they are asking however is where is it counted.  In the base room value (which gets modified by this 'm' value the OP defines) or as part of furnishings, which this hypothesis says is unaffected by the modifier.

Following with interest, and thanks for the link to Kipi's work which I missed somehow

Title: Re: Open room calculations
Post by: zzedar on April 12, 2013, 04:09:23 pm

Okay, here are my plans:
I have learned that internal doors count as part of v_f, not v_r. Thus, I can easily test external doors by switching a door between internal and external and seeing if the value changes.

I also want to check whether the multiplier shows up in my wealth summary in the stocks menu.

I should also probably check whether decorations on the designation building count as v_f or v_r -- I've been assuming, which I shouldn't. And I'm going to check whether items that just happen to be lying in the room count (with stockpiles).

Next, I'm going to check pillars -- walls that are completely surrounded by the room, and whether they count as perimeter tiles.

Then, I'm going to check constructed walls -- all I've done so far is with dug walls.

Anything else I should explore?

Title: Re: Open room calculations
Post by: Gentlefish on April 12, 2013, 08:10:36 pm

with constructed walls - check between blocks and raw stone. If I remember right, blocks are worth more than the raw material and may, then, play a factor in it. With that against engravings, we can see how much of a difference that would make.

Title: Re: Open room calculations
Post by: zzedar on April 12, 2013, 09:47:01 pm

Okay, I did some experimentation, and it looks like  non-internal doors don't count towards the value of the room at all. An exceptional gold door, which by itself has a value of 1500 -- enough to make a room "great" by itself -- is sitting at the entrance of a "meager" bedroom right now. However, there seems to be a bug here. Internal/external is only checked at the time when you resize the room. If a door in a room has its internal/external status flipped after the room is sized, that isn't taken into account in the calculations.

Title: Re: Open room calculations
Post by: i2amroy on April 13, 2013, 12:58:36 am

I think that is due to the fact that non-internal doors prevent the room from spreading underneath them (and thus neither they, nor the floor beneath them, is counted as part of the room).

Title: Re: Open room calculations
Post by: King Mir on April 13, 2013, 01:15:29 am

If the internal flag plays such a big role, you should see if it applies to hatches too. For completeness.

Title: Re: Open room calculations
Post by: zzedar on April 13, 2013, 01:31:41 pm

Quote from: i2amroy on April 13, 2013, 12:58:36 am

I think that is due to the fact that non-internal doors prevent the room from spreading underneath them (and thus neither they, nor the floor beneath them, is counted as part of the room).

Ooh, good point, I should check to see whether the floor tile counts.