How would I create a working body detail plan and define it in the raws? I used the wiki extensively for other purposes but I don't get how the body detail plans work.
There are (at least) five types of those; which exactly do you mean?
* Material-Defining: [ADD_MATERIAL] tags, assign a name (for example "MUSCLE") to a specific material template
(for example "MUSCLE_TEMPLATE")
* Tissue-Defining: [ADD_TISSUE] tags, assign a name (for example "MUSCLE") to a specific tissue template
(for example "MUSCLE_TEMPLATE") using the material names assigned so far.
It's worth noting that - despite the same names! - the material template "MUSCLE_TEMPLATE" is not
the same as the tissue template "MUSCLE_TEMPLATE", and neither is the material named "MUSCLE" the same as the tissue named "MUSCLE".
* Layer-Defining: [BP_LAYERS] tags, assigns tissue layers defined above to body parts chosen by either category (BY_CATEGORY), type (BY_TYPE) or specific name (BY_TOKEN).
* Position-Defining: [BP_POSITION] and [BP_RELATION] tags, define where in relation to each other the body parts are on a creature, chosen as above
* Size-Defining/Modifying: [BP_RELSIZE] tags, modify the body parts' [DEFAULT_RELSIZE] values, chosen as above
As for writing them down, you start a new text file (file extension: "txt") in the "raws/objects" directory, then start it with the following lines: