FLUX.1 Fill [pro] Worldbuilding Scene Concept Art: Distant Ridge Extension

Using the outpainting capability of flux-1-fill-pro for worldbuilding visual exploration: first provide a narrow-format distant concept image (ridge, lone tower, low cloud band), then use a mask to extend the canvas to both sides, filling in environmental depth under the same lighting and perspective. The work deliberately applies "spot editing" to atmosphere building—rather than redrawing the entire image, it lets the model continue the existing image's materials, color temperature, and sense of air within the white masked area, thereby producing a wide-format scene usable for an art book or storyboard background. The composition involves two generation assets: the original concept image serving as the editing base (image), and an extension mask at the same aspect ratio as the original with white only on both sides (mask). The prompt describes only what should appear in the white areas (extended ridgelines, distant hazy peaks, clouds lit by the same side light), and emphasizes maintaining consistent lighting, perspective, and brushwork with the existing image. For parameters, steps=50, guidance=60, and prompt_upsampling is disabled, to prevent the model from rewriting the description and deviating from the established worldbuilding. Applicable scenarios: aspect ratio expansion in film/game pre-production concept design, art book banners and keyframe backgrounds, and production pipelines that need to complete environments without regenerating the entire image. This model is an editing model rather than a text-to-image model, so the starting point of this work must be an existing image and a precise mask.