Overview
ControlNet guides rather than guarantees. The generated image follows the reference to an extent determined by the preprocessor, strength, model, and prompt.
Maximum strength gives the reference more control but reduces freedom. Zero strength disables the structural guidance entirely.
The correct preprocessor depends on the intended constraint. OpenPose is suitable for body arrangement, Canny and line art for outlines, depth for spatial structure, and segmentation for region placement. Selecting a preprocessor that does not represent the desired information weakens the result.
The workflow adds several nodes and connections, making layout and labeling more important. The first use of a preprocessor may also trigger an additional model download.
Using 768 rather than SDXL's preferred 1024 scale improves speed but compromises the preferred generation scale.