ModelMergeSD2_motorway_edition

SD 2.x is the version of Stable Diffusion the ecosystem quietly moved past - the checkpoint ecosystem never matched SD 1.5's, and the ModelMergeSD2 node exists because the architecture does, not because it's a hot destination for merges. If you're here, you're either maintaining an SD2.x model or finishing off a merge someone else started. This is its Motorway-ed clone.

The block layout

The structure is identical to SD1's - the node exposes one float per named region of the UNet:

• time_embed, label_emb - the conditioning inputs.
• input_blocks.0–input_blocks.11 - the encoder; lower indices handle coarse layout, higher indices finer features.
• middle_block.0–middle_block.2 - the bottleneck, the most influential region.
• output_blocks.0–output_blocks.11 - the decoder, where texture and finish live.
• out - the final output projection.

Same defaults, same trap: everything is 1.0, which means all-defaults hands you model2 wholesale. The practical workflow is identical to the SD1 node too - pick a base blend value for all the floats, then raise or lower individual blocks to steer composition versus finish. The KB's merge framing applies: per-block merging is how you decide which parent's strength shows up where, at the cost of some consistency.

The one genuinely useful detail: this node (and its SD1 sibling) work by long-prefix matching weight names to block names, so the ratio you set on input_blocks.3 covers every tensor whose name starts with that prefix. That's why the granularity feels right - it's whole-block, not per-layer, and that's what people actually want to control.

The inputs

• INPUT_model1_key (default model1) and INPUT_model2_key (default model2) - the two SD2.x models.
• The block ratios above, each 0.0–1.0, step 0.01, default 1.0.
• OUTPUT_MODEL_key (default MODEL) - where the merged model lands.

The wrapper keeps the ratios as widgets, turns the models into key strings, and keyed-writes the result. Runtime behavior matches stock ModelMergeSD2.

Install

One install for the whole pack. ComfyUI Manager, search "ComfyUI_agilly1989_motorway", or:

cd ComfyUI/custom_nodes
git clone https://github.com/agilly1989/ComfyUI_agilly1989_motorway

Restart ComfyUI. No requirements.txt, no model downloads.

Troubleshooting

• Result is pure model2? Every ratio defaults to 1.0 - set a base blend first.
• Don't cross-merge SD2.x weights with SD1.x or SDXL. The node will run; the output won't be usable. Use ModelMergeSD1 or ModelMergeSDXL for those.
• 'MotorwayClass' object has no attribute 'hash_' = a model key isn't in the Motorway; check the loaders ran and the key spelling matches (case-sensitive).
• Pack caveats: BETA, and the newest published version (1.1.7) disabled clone generation, so on a fresh install these _motorway_edition nodes may be missing from the menu. They're present in the 1.1.0–1.1.6 builds comfy.icu indexed.