Use a scale sketch to keep character sizes consistent
Pair character sheets with a shared-ground-line sketch so an AI video model can read both appearance and relative height.
Keeping a size difference stable across AI video shots is difficult when the prompt only says that one character is taller. A Higgsfield excerpt shared with this note proposes a separate pencil scale sketch of a giant and a boy. Fed back as a reference, the sketch gives the model a visible comparison rather than another sentence to reinterpret.
Give each reference one job: character sheets define faces, clothing, and other identity details; the scale sketch defines relative height and body proportion. Higgsfield’s public guidance supports using visual references to anchor details across shots, but the excerpt’s claim that a sketch “locks” the difference in every batch should be treated as a goal to test, not a guaranteed result.
Draw the comparison without perspective
Place every character in a front-facing, full-body neutral pose on the same straight ground line. Show the full height of each figure, including feet and head. Keep the camera level and orthographic-looking, with no foreground/background depth that could make one figure appear larger for the wrong reason. If a specific ratio matters, write it down and check the sketch visually.
Separate identity from scale
Attach the character sheets for appearance and the scale sketch for relative size. In the generation prompt, name those roles explicitly. Ask the model to preserve the same height relationship as the shot angle and composition change. This prevents the rough pencil sketch from unintentionally replacing the characters’ finished look.
Copy an adapted scale-sketch prompt
The supplied image shows only a brief explanation, not Higgsfield’s full original prompt. This is a reusable prompt reconstructed from the visible method; replace the bracketed details with your own characters and ratio.
Create a simple pencil scale-reference sketch of [character A] and [character B]. Show both characters together, front-facing and full-body, standing upright on one straight shared ground line. Use a level, neutral camera with no perspective distortion, no dramatic pose, and no foreground/background separation. Keep their feet aligned. Make [character A] exactly [desired height ratio or measured height] relative to [character B], so the difference is unmistakable at a glance. Use clean outlines and a plain background. This image is for comparing relative height and body proportions, not for defining final clothing, color, lighting, or facial identity.
Use both references in the video prompt
Keep the sketch in the reference set for each new batch or shot. Compare the generated characters against the ground-line sketch, particularly after close-ups, low-angle shots, or pose changes.
Use the attached character sheets as the source of each character’s identity, face, clothing, colors, and finished style. Use the attached scale sketch only for their relative height and body proportions. Preserve the same size relationship whenever both characters appear, including after camera-angle or pose changes. Do not copy the sketch’s pencil style into the final scene. If the framing makes the comparison ambiguous, include a shared ground plane or another clear scale cue.