DynaSolidGeo: A Dynamic Benchmark for Genuine Spatial Mathematical Reasoning of VLMs in Solid Geometry
Changti Wu, Shijie Lian, Zihao Liu, Lei Zhang, Laurence Tianruo Yang, Kai Chen
TL;DR
This work addresses the challenge of measuring genuine spatial mathematical reasoning in Vision-Language Models for solid geometry. It introduces DynaSolidGeo, a dynamic benchmark with 503 seed questions parameterizable into unbounded multimodal instances, rendering either randomized view images or 360-degree videos. Evaluation uses three metrics ($AA$, $PS$, $PA$) and a semi-automatic data annotation pipeline; experiments show large gaps between model families, notable degradation under dynamic evaluation, and evidence of data contamination on static sources. The benchmark mitigates memorization through dynamic generation and promotes progress in process-grounded reasoning for spatial problems.
Abstract
Solid geometry problem solving demands spatial mathematical reasoning that integrates spatial intelligence and symbolic reasoning. However, most existing multimodal mathematical reasoning benchmarks focus primarily on 2D plane geometry, rely on static datasets prone to data contamination and memorization, and evaluate models solely by final answers, overlooking the reasoning process. To address these limitations, we introduce DynaSolidGeo, the first dynamic benchmark for evaluating genuine spatial reasoning in Vision-Language Models (VLMs). Constructed through a semi-automatic annotation pipeline, DynaSolidGeo contains 503 expert-curated seed questions that can, in principle, dynamically generate an unbounded number of diverse multimodal text-visual instances. Beyond answer accuracy, we incorporate process evaluation based on expert-annotated reasoning chains to measure logical validity and causal coherence. Experiments across representative open-source and closed-source VLMs reveal large performance gaps, severe degradation in dynamic settings, and poor performance on tasks requiring high-level spatial intelligence, such as mental rotation and visualization. The code and dataset are available at \href{https://zgca-ai4edu.github.io/DynaSolidGeo/}{DynaSolidGeo}.
