LTD-Bench: Evaluating Large Language Models by Letting Them Draw
Authors: name: Liuhao Lin, name: Ke Li, name: Zihan Xu, name: Yuchen Shi, name: Yulei Qin, name: Yan Zhang, name: Xing Sun, name: Rongrong Ji
Organization: Tencent

Current evaluation paradigms for large language models (LLMs) represent a
critical blind spot in AI research--relying on opaque numerical metrics that
conceal fundamental limitations in spatial reasoning while providing no
intuitive understanding of model capabilities. This deficiency creates a
dangerous disconnect between reported performance and practical abilities,
particularly for applications requiring physical world understanding. We
introduce LTD-Bench, a breakthrough benchmark that transforms LLM evaluation
from abstract scores to directly observable visual outputs by requiring models
to generate drawings through dot matrices or executable code. This approach
makes spatial reasoning limitations immediately apparent even to non-experts,
bridging the fundamental gap between statistical performance and intuitive
assessment. LTD-Bench implements a comprehensive methodology with complementary
generation tasks (testing spatial imagination) and recognition tasks (assessing
spatial perception) across three progressively challenging difficulty levels,
methodically evaluating both directions of the critical language-spatial
mapping. Our extensive experiments with state-of-the-art models expose an
alarming capability gap: even LLMs achieving impressive results on traditional
benchmarks demonstrate profound deficiencies in establishing bidirectional
mappings between language and spatial concept--a fundamental limitation that
undermines their potential as genuine world models. Furthermore, LTD-Bench's
visual outputs enable powerful diagnostic analysis, offering a potential
approach to investigate model similarity.