Saying what not to draw

Ask an image model for a table and you get a table with two chairs, a place setting, a potted plant and a patch of floor underneath it. Nobody asked for any of that. The model is being helpful: it has seen a million pictures of tables, and tables come with company.

For a game that builds its rooms out of separate pieces, that helpfulness is a reject. A table that owns its chairs can't be pushed against a wall or paired with another table. The picture isn't bad; it just can't be used.

So the studio's art roles agreed on standing exclusion lists — a fixed block of wording attached to every furniture request, and a second one for kitchen stations, naming exactly what must not appear. Four decisions in how it's written turned out to matter more than the list itself:

• Lead with what you do want. An exclusion list read on its own tends to summon the things it names, so "Draw only the object" comes first and the list follows.
• Every noun on the list has actually shown up uninvited. No guessing at what a generator might add. If it has never arrived unprompted, it doesn't earn a place.
• Cut the catch-alls. "Or other props" carries no weight and costs reading length, which is the scarce thing in a prompt.
• Keep the lists apart. Furniture and stations have separate lists, so neither drags the other's nouns into a request where they'd do harm.

Two of the lines came with warnings attached, written down beside them. "No chairs" is permanent for every piece of furniture, because chairs are always drawn separately. "No text, label or sign" is safe only while signage is composited afterward rather than generated — if that ever changes, any request for a sign has to override the line, or it will fight itself.

The wider point is a working principle for anyone directing a generative model: a request is two halves, and most people write only one. The subject is the easy half. The other half is the convention the model doesn't hold — everything your pipeline will do itself, and therefore everything that must not be baked into the picture. Writing that half down once, and keeping it where the requests are built rather than in a brief someone has to remember, is the difference between a piece that drops into the game and a piece that has to be asked for again.