Luma Ray3.2 takes 16 keyframes; on Sume, chain first/last-frame clips

Luma states that Ray3.2 accepts up to 16 keyframes per clip. Sume has no Ray3.2 id, and its video models take at most two frames, a first and a last, so the nearest workflow is one clip per pair of neighbouring keyframes: 16 keyframes make 15 clips, joined afterwards in Timeline 1.0. You get your storyboard hit, but as 15 separate generations rather than one continuous move.

Ray3.2 facts are from Luma's announcement, read 2026-10-02. Sume limits are from the Video Router docs and Timeline docs.

How do I turn keyframes into clips?

Send keyframe N as image_url (first frame) and keyframe N+1 as end_image_url, with a prompt for the motion between them. end_image_url requires image_url. The frame_images array accepts at most two entries. Seedance 2.5, Wan 3.0 and MiniMax H3 are all listed with first-and-last-frame input.

What does this cost in clip length?

Each hop is its own clip with its own minimum: 2 s on wan-3.0, 4 s on seedance-2.5, 5 s on minimax-h3. Fifteen Wan hops at the 2-second minimum is a 30-second sequence; fifteen Seedance hops at 4 seconds is 60.

Each clip is a separate job billed at list times 1.25, so budget per clip.

How do I join the clips?

Timeline 1.0 takes one audio spine and up to 200 ordered video slots, with fade and dissolve transitions, so 15 clips fit. Use audio.mode: "silence" for a silent cut or supply a soundtrack. The default output is 1080 by 1920, so set output.width and output.height for landscape; see the Timeline sizing post.

Expect small jumps at the joins, since each clip is generated separately. One Ray3.2 clip avoids those joins; chained clips do not.

Start small: try one hop between two keyframes at 480p, check that the motion matches your storyboard, then script the remaining hops with one Idempotency-Key per hop so a retry never bills twice.