Mosaic: Assemble (Folder)

The other half of the tiled-diffusion story. MosaicTileExport cuts an image into tiles, you process them, and MosaicAssembleFromFolder puts them back. This is the folder-based variant: instead of taking a batch tensor, it reads tiles straight from a directory - which is exactly what you want when the tiles were processed by an external tool, a second ComfyUI instance, or any pipeline that wrote files instead of keeping tensors in memory.

How it works

The node globs a folder for files (default output/tiles/*.png), sorts them, and places each tile onto a rows × cols canvas. The placement logic is where it gets interesting, and the star is order_mode:

• row_major / column_major / snake_row / snake_col - the classic scan orders, for when tile order in the folder matches grid order.
• regex_filename_order - the killer feature for real tiled-diffusion use. It parses row and column numbers out of each filename with regexes (regex_row default r(\d+), regex_col default c(\d+)) and places every tile at its exact grid position. Filenames like tile_r01_c03.png just work, regardless of folder sort order.

It also has the blending machinery that makes overlapping tiles look like one image instead of a patchwork - that's the part the tiled-diffusion community cares about, because naive seams are the classic artifact. The overlap_blend modes include average, alpha_over, add, multiply, screen, lighten, darken, weighted, feather_linear, and feather_cosine, controlled by overlap_x/overlap_y, blend_weight, and feather_px. For a seamless stitch, feather_linear or feather_cosine with a reasonable feather_px is the mode you'll actually reach for - the KB's tiled-upscaling notes call out patchwork artifacts as the #1 thing to avoid.

Inputs that matter

• folder, glob_pattern - where the tiles are and what they're named.
• rows, cols - the grid size.
• order_mode - regex_filename_order for robustness, row_major otherwise.
• overlap_x, overlap_y, overlap_blend, feather_px - seam handling for overlapping tiles.
• enforce_tile_size + target_w/target_h - force every tile to a uniform size before placing (tiles that don't match get resized).
• export + filetype/quality/basename/subfolder - whether to also save the result.

Outputs

image - the assembled IMAGE. save_path - the written file path when export is on.

How to install

Part of the orion4d/ComfyUI_DAO_master pack:

cd ComfyUI/custom_nodes
git clone https://github.com/orion4d/ComfyUI_DAO_master.git
pip install -r requirements.txt

Restart ComfyUI. No models.

Common issues

The usual failure is tile placement: if tiles are landing in wrong cells, either your filenames don't match the default r(\d+)_c(\d+) regexes (check regex_row/regex_col and base_index - zero- vs one-based counting is a classic mismatch), or you're on a plain scan order when the folder isn't sorted as expected. Empty canvas? Check glob_pattern actually matches your files. And remember the default export writes a file - if you're seeing an unexpected save, that's the export toggle.