> ## Knowledge Base Index > Fetch the complete knowledge base index at: https://help.comicink.ai/sitemap.xml > Use this file to discover available pages before exploring further. > Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash). # Choosing a model and scene length In a Story Video these choices are made **per scene**, not once for the whole video. Each scene card carries its own **Model** selector and **Time** selector, with a **live credit estimate** that updates as you change either one — so you can see what a scene will cost before you render it. Different scenes in the same video can use different models and different lengths. A dialogue beat and an establishing shot do not have to be treated the same way. --- ## What the models differ on The selectable models are **Seedance 2.5**, **PixVerse C1**, **Veo 3.1** and **Wan 2.7**. **Seedance 2.5 is the default** — every new scene renders on it unless you pick a different model for that scene. The three differences that actually affect your choice are: - **Whether the model will animate your characters' faces.** Only the default, Seedance 2.5, reliably accepts reference art that shows a face. The others can refuse the scene — see the next section, which also explains the automatic retry. - **How many reference images each model accepts.** Your storyboard frames, location, cast and asset references all count toward this. Models differ in how many they can take in. - **Which durations each model offers.** The Time selector shows the lengths the currently selected model supports, so changing the model can change the options in the Time list — and can change an already-chosen length (see below). Everything else is a matter of look and feel. Models render motion and style differently, and the honest advice is to try a scene on one, look at the result, and switch if it isn't what you wanted. Re-rendering a single scene is cheap relative to redoing a video. --- ## Some models refuse scenes that show character faces Every model except the default can **refuse to animate a scene whose reference images show a face** — and that includes your own illustrated characters, not only photographs. You'll see a warning line under the Model picker whenever you choose one of these models, so it's never a surprise. If it happens, you don't have to do anything: the scene is **retried automatically on Seedance 2.5** before it is reported as failed, and you are not charged twice. You'll get a clip; it just won't be from the model you picked. If you want that model's look for a scene, the reliable way is a scene whose references don't show a face — an establishing shot, a landscape, an object. Photographs of real people are a different matter: every model refuses those, by policy — see [Content policy](https://help.comicink.ai/en/article/content-policy-and-what-we-cant-generate-1qennwp/). ## Changing the model can change the duration Each model has its own range of lengths, and some render exactly one length — **Veo 3.1 always renders 8 seconds**. When you switch a scene to a model that can't render its current Duration, the Duration is **clamped to what the new model can do**, so the number you see is always what will actually be rendered. A 15-second scene switched to Veo 3.1 becomes an 8-second scene; switch it back and set 15 again if you want the longer clip. The Duration you set is the scene's slot on the timeline; the model decides the clip's real length within it. ## When a scene is blocked from rendering **A scene carrying more reference images than its chosen model supports cannot be rendered.** This is the most common reason a scene refuses to start, and it is not a failure or a bug — it is caught before you are charged. You have two ways out: 1. **Reduce the references on that scene** — drop a cast member, asset or location the shot does not really need, or remove a storyboard frame. 2. **Switch to a model that accepts more reference images**, then render again. Remember that storyboard frames count toward the total. Adding a second storyboard beat to a scene that was already near the cap can be what pushes it over. --- ## Resolution: everything renders at 720p There is **no resolution choice** when you set up a scene. **On web, every render is 720p** — the resolution picker was removed, so the Model and Time selectors are the only per-scene render settings. **1080p is a paid upscale**, applied to the finished video at publish time rather than chosen at creation time. See [Exporting and sharing Story Videos](https://help.comicink.ai/en/article/exporting-and-sharing-story-videos-it6hud/) for how the upscale works in the Publish modal. **On iOS:** the app still displays a resolution picker, but 1080p is clamped to 720p on the server until its next App Store release. Choosing it changes nothing. --- ## What a scene costs Cost scales with both the **duration** you pick and the **model** you pick — a longer scene costs more than a short one, and models are not priced alike. The live estimate on the scene card is the number to trust, since it reflects the exact combination you have selected. For what each part of a video draws from your balance, see [Story Video credits](https://help.comicink.ai/en/article/story-video-credits-and-costs-1lj1797/); for balances, credit packs and what happens when a render fails, see [How credits work](https://help.comicink.ai/en/article/how-credits-work-1m9t59m/). --- ## Next steps - [Rendering scenes](https://help.comicink.ai/en/article/rendering-scenes-per-scene-vs-generate-all-z30txn/) — starting a render and tracking it. - [Storyboards: guiding how a scene looks](https://help.comicink.ai/en/article/storyboards-guiding-how-a-scene-looks-dx8v9m/) — frames that count toward the model's reference limit.