Bay 12 Games Forum

Meph, the glass mod that was mentioned is probably this one:
http://dffd.wimbli.com/file.php?id=4071
Which is linked to in this thread:
http://www.bay12forums.com/smf/index.php?topic=79662.0

It's very much a Chemistry or Alchemy type mod. Might well be of interest.

Since you didn't mention it, and because a lot of people forget to do this at first:

Did you add entries to the entities file? Specifically
   [PERMITTED_BUILDING:BLOCKCRAFT]
   [PERMITTED_REACTION:MAKE_BONE_CABINET]
   [PERMITTED_REACTION: etc. You'll need one for every one of the reactions, of course, which can be quite the list.

If you've already done this, then my apologies, but that's the usual reason that new workshops and reactions don't show up, and needs to be checked before any debugging of reactions is done.

So, hypothetically speaking, if we were to make the very minor modification of changing the Dwarven active season from Autumn to Spring, and make sure to build a Depot asap, could we stop the game sending out either of those first two migrant waves at all?

Not that I've ever tried to butcher them but skimming through the raws, I don't see why they wouldn't be. Firstly, most vermin have the [NOT_BUTCHERABLE] tag, but Creepy crawlers don't. Secondly, they have a size of 1,000, compared to a hamster's 150, a cave spider at 50, and a rat at 300. Since both adult rabbits (500) and cavy (800) are smaller than a creepy crawler is, and those can be butchered, I don't see any problem there.
It's just unusual to see a butcherable creature that can spawn randomly, rather than having to be bred.

Remove [PERMITTED_JOB:FURNACE_OPERATOR], then grant them access to a reaction that makes the metal types that you want them to use. That should do it.

I've dug around pretty thoroughly in Masterwork to pick out some things for my own homebrew mod, so this is actually pretty interesting for me. To answer a couple of your questions:

Why aren't some reactions available to the player, and does this mean that the products won't work for them?
What a fortress can do and what a civ can do are actually very different things. A civ will have access to the results of any reaction permitted to it in the entity files, regardless of whether it's able to provide the reagents.
For example: I can remove Furnace Operator (and the list of permitted reactions) as a valid skill for, say, humans. This will immediately prevent them from being able to get the products of smelting any ores. In fact, they won't be able to make use of metals at all. But if I give them back the bronze-making reaction, even though they will never have copper or tin, they'll now have access to bronze.
So, by allowing the dwarves to have a reaction that makes crates, but not allowing the player access to it, the crates can be bought at embark and from traders but not produced on-site. It's nice, and it works pretty well.

Why are crates made of soap?
Good question. I can only hypothesise that it's because soap appears in the misc section at the end, and thus it's a lot easier to find than if they were tools, say, and buried in the middle of the list amongst all the different flavours of tool and the materials that they're made of. Tools would certainly work, but it's a bit neater as soap. Incidentally, you can also use crates as building materials, which would be an interesting way to keep an emergency store of certain supplies. That wouldn't be possible with tools.

I made a mistake while standardising animal products and somehow erased the concept of meat from the game. It was still in the raws, but the game just didn't care. All that was left was skin and bone. I thought that it was funny enough that I was tempted to keep it, but since for some reason I had a dwarf endlessly looping through trying to process a non-existent cheese and creating an infinite amount of skin... I decided not to.

I've just tested what Squishynoob posted and it works almost perfectly.
Basic setup: current version with Phoebus tileset preinstalled. Modded with the above and nothing else. Didn't even change the default .ini settings. Everyone's in a clearing with a lot of animals and some rocks (to build workshops with). Orders changed to 'gather refuse from outside' for obvious reasons.
It produces a glob of animal skin (dog 12, yak 14 etc.) and a tanner will snap it up and produce the relevant number of pieces of leather. If it doesn't get grabbed from the workshop, it gets stored in the fat/tallow stockpile. This makes sense, as it's a glob, so that's the obvious place for it, although there's no corresponding entry in the stockpile settings for 'skin' to turn off. However, as soon as it's stored in the stockpile, my dwarves runs over and clean, instantly destroying it. Unfortunate. It can be bypassed by not having a fat/tallow stockpile, since they only seem to clean it up if it's in a stockpile but that's not ideal. Does anyone know why fat/tallow globs aren't cleaned? We might be able to do something there.
In broad terms, this is great, and you're able to produce very large amounts of leather fairly easily and quickly. If you have tanners at the ready, the cleaning issue is irrelevant, but if your tanner's on break, you may as well consider that skin wasted, unless you forbid it the moment as it hits the pile. As soon as you unforbid it, your tanner will probably grab it. I had three tanneries and five tanners (and two butchers), and when I unforbid three globs, they were all immediately tanned rather than cleaned up. So it should work out.
The biggest complaint that people are likely to have is the sheer amount of leather produced. Both a yak and horse produced 14, which is somewhat high, but a dog produces 12. It's probably related to the bug that has hooved creatures producing less meat than non-hooved of a similar size (which means that yaks and horses should be producing far more skin, it's just that the bug reduces it again). I've played around with the input side of the reaction, and it's quite happy to produce, for example, 1 leather for every full 3 skin in the pile. Any excess are lost. This would let you reduce the worst effects of this, but you're still going to have problems when it comes to some animals. I suspect that elephants are going to be rather productive.
Assuming that this actually is related to that hooved bug, you could potentially have two different skin types in the way that Sphalerite has multiple types, but rather than going crazy with working out which one to use based on size, this could just be based on hooved and non-hooved. Then you could have two reactions - one taking items at, for example a 9:1 ratio (non-hoof), and the other at 3:1 (hoof). That way a yak with 14 skin would produce 2 leather, and a dog with 12 skin would produce 1 leather. Tinker as seems appropriate. It would be a fair bit of work to tweak every animal, but certainly doable. (Potentially: Find/replace to remove all skin tags in an animal entry. Then replace all hoof tags with a hoof tag followed by a skin tag. Look for what the non-hoofed have that's unique to them and do something similar)

I like this tweak and will probably play with it some more, and depending on what I can get to work, might use it permanently in my homebrew setup. I'm also wondering if I could do something similar with bones... Butcher them into glob form, then have an auto-reaction turn them into individual bones. Something to look into later.