Text-first approach: This method flattens everything into plain text, primarily relying on OCR. Then it applies retrieval techniques like BM25, classic chunk-based RAG, or graph-based methods like GraphRAG or RAPTOR.

Layout-first approach: This one preserves the original document layout. It segments content into structured blocks (paragraphs, tables, figures, equations) and uses multimodal retrieval or LLM-based processing pipelines (like DocETL) to handle relevant chunks.