In this work, we probe the ability of a language model to demonstrate spatial reasoning from unstructured text, mimicking human capabilities and automating a process that benefits many downstream media applications. Concretely, we study the narrative-to-play task: inferring stage-play layouts (scenes, speaker positions, movements, and room types) from text that lacks explicit spatial, positional, or relational cues. We then introduce a dramaturgy-inspired deterministic evaluation suite and, finally, a training and inference recipe that combines rejection SFT using Best-of-N sampling with RL from verifiable rewards via GRPO. Experiments on a text-only corpus of classical English literature demonstrate improvements over vanilla models across multiple metrics (character attribution, spatial plausibility, and movement economy), as well as alignment with an LLM-as-a-judge and subjective human preferences.
Figures & tables
Figure 1: We propose a Dramaturg Spatializer that transforms long-form narrative into structured stage layouts. The model assigns dialogue and characters to canonical positions on a discrete grid—depth ( front, middle, back ) and lateral placement ( left, center, right )—with temporal blocking to produce plausible staging from text. This automates a “text-to-play” process for applications such as game previsualization and spatial audiobooks.
Figure 2: Overview of our Spatializer training pipeline. Left: A strong teacher LLM produces pseudo stage-play annotations via Best-of- N sampling and rejection SFT under our deterministic dramaturgy evaluator. Right: The resulting Spatializer-SFT is post-trained with RL from verifiable rewards (GRPO): for each passage, we sample candidate spatializations, score them with the deterministic evaluator, compute group-relative advantages (with KL regularization to a frozen reference model), and update the policy to obtain Spatializer-GRPO . The model outputs a reasoning trace (e.g., per-quote placement plan) and the corresponding stage-grid layout.
Model
Deterministic suite components
AVG
Quote Attr.
Alias Res.
Stage Pos.
Char. Pos.
Move. Coh.
Scene Trans.
Proprietary models
Claude Sonnet 3.5
96.0
97.0
87.0
85.0
77.0
51.0
82.0
GPT-4.1
94.0
99.0
65.0
84.0
90.0
51.0
81.0
GPT-4o
95.0
99.0
68.0
83.0
84.0
51.0
80.0
Claude Sonnet 4
96.0
97.0
85.0
83.0
69.0
50.0
80.0
Table 1: Leaderboard across models. Metrics include Quote Attr. (Quote Attribution), Alias Res. (Alias Resolution), Stage Pos. (Stage Positioning Validity), Char. Pos. (Character Positioning), Move. Coh. (Movement Coherence), and Scene Trans. (Scene Transitions). Top scores are bolded.
Figure 3: Additional analyses. (a) Distribution of per-example AVG scores over GRPO, SFT, and Baseline models. RL training shifts mass and reduces degenerate failures, indicating improved reliability beyond mean score gains. (b) Deterministic macro score (%) versus GRPO steps when swapping the backbone (Qwen3 vs. LLaMA 3.3); the horizontal line denotes the best proprietary API baseline (83.45%). (c) ROC curve for a logistic regression that predicts whether listeners prefer audio A over B from the deterministic dramaturgy score difference Δs=s(A)−s(B) . The classifier achieves AUC=0.701 with Brier score 0.186 .
Figure 4: Challenging qualitative cases for spatialization diagnostics. Left: case probing consistency between generated reasoning and emitted layout. Right: case probing continuity when new characters enter an already-populated scene.
Model
Quote Attr.
Alias Res.
Stage Pos.
Char. Pos.
Move. Coh.
Scene Trans.
AVG
Spatializer-GRPO
91.75
99.09
92.11
92.54
98.25
57.40
88.52
-Only JSON
82.40
93.00
76.62
83.00
89.91
48.03
78.83
-Quote+Alias
27.02
31.57
51.00
72.00
75.00
39.00
49.26
-Stage Pos
95.19
99.23
76.00
73.74
69.00
51.07
77.37
-Character
94.00
99.00
66.45
57.76
65.95
49.00
72.03
-Movements
93.87
99.37
77.74
88.02
65.00
51.07
79.18
Table 2: Reward-component ablations for the 8B spatializer trained with GRPO. We retrain variants using only JSON validity as reward or by removing one deterministic reward category at a time, and then evaluate using the full deterministic suite. Scores are percentages (higher is better). AVG is the macro-average over Quote Attr., Alias Res., Stage Pos., Char. Pos., Move. Coh., and Scene Trans. (excluding Valid JSON).
Evaluator
Agreement with human pref.
Spearman ρ↑
Rank Acc. ↑
LLM-as-Judge (Abs.)
0.88
86.7
LLM-as-Judge (Rel.)
0.86
86.7
Deterministic
0.95
93.3
Table 3: External validity of automated evaluators against human pairwise preferences on binaural renderings. We report Spearman correlation ( ρ ) between evaluator-induced system rankings and human win-rate rankings, and rank accuracy (Rank Acc.) over all system pairs. Best results are shown in bold .
Model
Dramaturgy Prompt
Minimal Prompt
Zero-shot models
Llama-4-Scout
83.39%
83.25% ↓0.14
Llama-3.3-70B-Instruct
83.39%
82.05% ↓1.34
Llama-4-Maverick
83.14%
82.07% ↓1.07
gemma-3-12b-it
80.00%
78.31% ↓1.69
Qwen3-8b
78.16%
77.82% ↓0.34
Table 4: Prompt-sensitivity ablation. We compare the deterministic macro score (AVG) under our full prompt (explicit dramaturgy constraints) versus a minimal prompt that gives only a high-level task description. Drop is computed as (dramaturgy prompt) − (minimal prompt), so larger values indicate stronger dependence on explicit prompt constraints.
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
Figure B.1: Extra results: test-time selection and training-data scaling. (a) Best-of- N at inference time for Qwen3-8B : we sample N candidate spatializations per passage and select the highest-scoring one using three ranking signals— Same Model (self-judging with the LLM-as-a-judge prompt), Bigger Model (GPT-4.1 as judge with the same prompt), and our deterministic dramaturgy evaluator ( Oracle ). Increasing N improves the selected output for all scorers, with the largest gains under the deterministic oracle. (b) Data scaling for Spatializer-SFT : we fine-tune the same base model with increasing numbers of supervised training examples and evaluate the resulting model on the same test set. Performance rises monotonically with dataset size, with diminishing marginal gains at larger scales.
Stage I
Stage II
Config
SFT
GRPO
Training Hyper-Parameters
Base model
Qwen3-8B
Qwen3-8B
Optimizer
AdamW
AdamW
Learning rate
5×10−5
1×10−6
Training epochs
1
15
Appendix
Table D.1: Training recipes for Spatializer . Stage I : supervised fine-tuning (SFT) on PDNC-Fanfic . Stage II : GRPO post-training with a deterministic dramaturgy reward on PDNC . 5400 (p)+4096 (r) means 5400 are used for the prompt while 4096 are used for the answer.
Figure E.1: Stage-Play Generation Prompt. We use the following prompt template to convert a quoted passage into a staged play with canonical speakers, dramaturgically grounded stage positions, and scene splits, outputting structured JSON.
Figure E.2: Minimal Dramaturgy Prompt. A simplified prompt template that performs canonical speaker mapping, coarse stage positioning, and scene splitting with minimal dramaturgical constraints, outputting structured JSON.
Figure E.3: LLM-as-a-Judge Prompt. We use the following prompt to score candidate spatializations (speaker attribution + stage positions + scene metadata) against ground-truth speakers and canonical mappings, producing per-criterion integer scores in JSON.