BMAB SD-WebUI API ControlNet

What it is

This node configures a ControlNet unit for BMAB's webui bridge to send over to a remote Automatic1111-style server - it doesn't run ControlNet itself, it packages the settings and hands them to BMAB SD-WebUI API T2I or BMAB SD-WebUI API I2I through their optional controlnet socket. If you've ever used Mikubill's sd-webui-controlnet extension on A1111, the field names here will feel exactly like home, because that's precisely what this is proxying.

The mode and resize_mode options in particular - "Balanced" / "My prompt is more important" / "ControlNet is more important", and "Crop and Resize" / "Just Resize" / "Resize and Fill" - are lifted verbatim from that extension's UI. This isn't ComfyUI's native ControlNet loader wearing a different name; it's literally a remote-control panel for the classic A1111 extension, running on whatever server your BMAB Server node points at.

Inputs and outputs

model and module are both dynamic dropdowns - the ControlNet checkpoint and the preprocessor, populated from whatever's actually installed on the remote server rather than a fixed ComfyUI list. weight (0–1, default 1), start, and end (both 0–1, default 0 and 1) map to the classic guidance strength and start/end step fractions - the same start/end controls that shipped in the A1111 extension back in February 2023 for things like targeted hand fixes, letting you end control partway through the steps and free the later ones for the model's own detail.

mode and resize_mode are the two three-way dropdowns above. image is where you feed the picture the preprocessor runs on - wire an IMAGE output into it, or leave it disconnected and pick from the dropdown, which defaults to None.

There's one optional input, also called controlnet, which is how you stack multiple units - plug a previous ControlNet node's output into the next one's optional input to build up a multi-ControlNet chain, the same stacking pattern the A1111 extension supports natively. The single output, controlnet, is what feeds into T2I or I2I.

How to install it

Through ComfyUI Manager, search comfyui_bmab - it installs the pack along with comfyui_controlnet_aux (Fannovel16) and ComfyUI_IPAdapter_plus (cubiq), both required. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/portu-sim/comfyui_bmab.git
cd comfyui_bmab
pip install -r requirements.txt

then clone and pip-install the two dependency repos the same way, restart ComfyUI. Note that installing comfyui_controlnet_aux here is about local preprocessing elsewhere in the BMAB pack - this node's own preprocessing runs remotely, on the server.

Common issues

Empty model and module dropdowns mean the same thing they do everywhere in this node family: the remote server either isn't running, isn't reachable, or wasn't launched with its API flag enabled. Get that sorted before expecting anything to populate.

Because the ControlNet model list is queried live from the server, it's easy to assume a model is available just because it works fine in ComfyUI's own node graphs - remember these are two entirely separate installs with separate model folders, so a ControlNet checkpoint has to actually be installed on the webui side to show up here.

And since start/end follow the classic A1111 convention rather than ComfyUI's, don't assume the defaults (0 to 1, meaning full-strength across every step) are what you want - the community's standard move on newer setups is often to end control around the halfway mark rather than let it run the whole way, which this node fully supports but doesn't default to.