Making a model for the game

Any model that is not a character goes from a one-line description to the file the game loads through tools/props (README): a concept image drawn to the style guide, a Tripo model of it with its textures, and a free clean-up in Blender that keeps them (D14). This skill is the order of work and the decisions around those steps.

The style guide is docs/art-style.md (D14). The style is textured, lightly stylised realism: real materials in detailed textures, a little shaded and simplified, neither photoreal nor cartoon. The guide decides how anything looks: shapes, materials, budgets, the concept prompt and the checklist. Read it before deciding anything below, and judge every concept and model by it. Don't restate it or work around it; if it is silent or wrong for a case, say so to the developers.

Not here: characters, bodies and gear (the character skill); item icons (item-icons); anything Tripo does outside this pipeline (tripo). A prop for an opening is made here like any prop. A building kit's pieces (a ridge capping, a bargeboard, a frame's member, a log) are not: a model of one is kept as source art in art/kits/<kit>/<piece>/model.glb, and tools/kits fits it, bakes its textures into the kit's atlas and writes it into the kit's pieces file (D251, D258; tools/kits/README.md, docs/building-plan.md); the game's layout code only places them (D177).

1. Decide what it is

It is	Its model goes in	The game finds it in
Furniture, a prop or a station	assets/models/props	assets/data/builds.ron, an Items variant: file, dims, cost; a station also in stations.ron
A door's or shutters' leaf	assets/models/openings ("into": "openings", "anchor": "hinge")	builds.ron's fittings: model, how it hangs, dims of the leaf its first hole takes, the holes it fits, cost
A tool or weapon	assets/models/tools ("into": "tools"), standing on the end of its handle, parts Wood and Metal	items.ron; its held look is made from it by tools/characters/fit_held.py
An item lying on its own, such as a material	assets/models/items/<item>.glb, where the game looks for it (no item has one yet)	items.ron; its icon by item-icons
A tree, bush, plant or flower	Not a model: grown by rules from bark and leaf cards (D222)	assets/data/flora.ron, a kind with grown (below)
A rock	assets/models/nature, from a CC0 scan (tools/props/scans.ts, art/scans.json)	assets/data/flora.ron, a kind (below)
A village piece, such as the well or a market stall	assets/models/props, with the props	builds.ron, under Hidden until it can be built

A creature or animal is not on this pipeline yet: it needs a rig (tripo rig --type other) and animations. Ask the developers before starting one.

Then, from the style guide:

• Size: life size (D110). A real one's width, height and depth in metres, dims, along glTF's X, Y (up) and Z (its front): the model is made to exactly that, and its catalogue entry states the same.
• The model contract (D303, art-style.md): its anchor (base, the middle of its base, by default; hinge for a leaf) and the sockets code needs (a leaf's hinge and handle, a seat's seat). The game places it from these alone; never give a model an offset, turn or scale in code or in the catalogue.
• Budget: the triangles its kind may have, from the guide's table. Things placed by the thousand, such as trees and rocks, stay low in their range.
• Materials: what each part is made of, true to life (weathered pine, fieldstone, wrought iron). The concept and Tripo's textures carry them, kept by default (D304); a part that glows is picked out by roles with Fire in them. palette: true and palette roles (from PALETTE in tools/characters/look.py) are only for a tool, whose held look is coloured by its parts, and for flora until it can read which parts of a textured model sway (step 6).
• Detail: "generator": "h3.1" for a piece seen close and often, such as a building kit's, which Tripo models and textures in more detail; the low-poly p1 otherwise.
• Variants (D182): most things come in many. Plan the parts a variant would swap. A kind of tree or rock wants two to four models, each its own concept and model; plants in quantity read as one kind only if their models differ.

2. Write its prop.json

One folder per model in art/props, named for it: art/props/<name>/prop.json, as the props README describes.

subject is what the thing is, what it is made of and its setting's motifs, true to life and simplified, never invented: "English oak tree, mature: a short, thick, gnarled trunk splitting low into heavy crooked limbs …". Nothing about style or framing: the tool appends the style guide's concept paragraph word for word.

3. Draw the concept (free) and look at it

node tools/props/props.ts concept <name>

Up to 100 images a month are free. Read art/props/<name>/concept.png and check it against the guide: silhouette, big-medium-small shapes, real materials a little shaded (not photographic, not cartoon), touching parts that differ in lightness, true proportions, and even light with no cast shadows, which Tripo would paint into the texture. Each --again is a new roll; change the subject rather than rolling many times. A concept for a new kind of thing, or several at once, goes to the developers before anything is spent: show them the images side by side.

4. Ask before spending

A model costs about 50 Studio credits (views, a P1 model textured at 2K, then its normal, roughness and metal maps), about 55 with h3.1 (prices in tools/tripo/README.md). Check the balance (node tools/tripo/tripo.ts balance) and say what it will cost. Several models, or more than about 100 credits, needs the developers' go-ahead.

5. Model it, then make it ours

node tools/props/props.ts model <name>    # about 50 credits: art/props/<name>/model.glb, with its PBR maps
node tools/props/props.ts refine <name>   # free, in Blender: the game's file, and a sheet

refine needs Blender (tools/blender). It welds the model, cuts it to the budget, keeps its textures at its budget (2K colour and normal maps for a prop 1.5 m or more, 1K below; or, with palette, gives every face a role), shades it smooth across curves and hard at creases, stands it facing +Z, level, at exactly its dims, its origin its anchor, with its sockets, and draws tools/props/out/<name>.png (four views beside a figure, in the game's light) with checks in out/<name>.json: triangles, size, loose parts. Look at both. Fix what comes out wrong in prop.json and refine again, which is free: turn for a front facing the wrong way, budget, flat, block; reference and grade so the pieces of a kit share one material and one colour grade; match for a role model whose texture paints a part in another shade.

6. Put it in the game

Add it to its data file (the table in step 1). A tree, bush, herb or flower is not made through this pipeline at all: it is grown (D222), a kind in flora.ron with grown naming its habit or shape, its bark (a material from tools/textures) and its leaf card (a picture on a flat blue background, laid in the atlas by textures.ts cards); the file's header says each part. For a rock, or another modelled kind, in flora.ron, which colours and sways models by role:

• models: its files in assets/models/nature, two to four for variety.
• colours: every role its models use, each with our colour and whether it is Foliage (moves in the wind) or Firm. A role left out takes the shared colours, whose default is foliage green, so bark left out turns green and sways.
• sway, grows (its layer, and where in it: below, above, chance; the order of kinds decides which is tried first), size (life size), and cut (what cutting takes and gives, as the other trees do).

7. Check it in the game

cargo run -p terra_sandbox -- --experiment workbench --model models/character/base.glb --prop <File> --sides 0 --sheet shots/<name>
cargo run -p terra_sandbox -- --experiment workbench --model models/character/base.glb --model models/nature/<File>.glb --sides 0 --sheet shots/<name>

The first is for anything in the build catalogue, drawn as when placed; the second for any model, such as a tree, beside a body for scale. For growing things, also see them where they grow: a scripted run of the play experiment with --at and --face near them, and --shot. Go through the style guide's checklist, and run cargo xtask contract: it holds every model the game places to the model contract, its size, anchor, sockets and, for a leaf, its fit in its hole, and cargo xtask check runs it too. The workbench draws its box (green when it keeps the contract), origin and sockets.

8. Commit

In one commit: art/props/<name>/ (prop.json, concept.png, concept.prompt.txt, model.glb, which are source art and cost credits to remake), the file in assets/models/, and the data entry. tools/props/out/ and shots/ are not committed. Pull, check and push as AGENTS.md says.

Where this pipeline falls short of the guide

The style guide lists what does not yet follow it ("Where the pipeline stands"). The ones that touch this skill:

• Plants are grown, not modelled (D222), so a textured Tripo plant has no place in flora.ron; a modelled kind there is drawn in its kind's material, projected onto it, not its own textures.
• No approved image in the style yet. Concepts are drawn from the guide's paragraph alone. Once one is approved, put it in art/style/ as reference.png and props.ts gives it as a reference.