Models Reference
1stUnit gives you six models through a single Runway account: three image models and three video models. They have different strengths and accept different kinds of inputs. This page covers each one so you can pick the right tool for the job.
Quick comparison
| Model | Type | Good for | Inputs |
|---|---|---|---|
| GPT-Image-2 | Image | Stylized images, clean compositions, text rendering. | Free-form references. |
| Nano Banana Pro | Image | Photoreal images, especially of people. Strong character consistency. | Free-form references, with Char checkbox for character images. |
| Nano Banana 2 | Image | Faster, lighter version of Nano Banana Pro. | Free-form references, with Char checkbox. |
| Gen 4.5 | Video | Image-to-video with a start frame. Smooth motion, cinematic feel. | Optional start frame, or text-to-video. |
| Seedance 2.0 | Video | Either multi-reference or keyframe-driven video. Good for stylistic control. | Multi-reference set, or start and optional end frame, or text only. |
| Veo 3.1 | Video | High-quality video with optional audio output. | Optional start and end frames, or text only. |
Image models
GPT-Image-2
OpenAI's image model, accessed through Runway. Pricing is 20 credits per image at standard resolutions and 41 credits at 4K. Aspect ratios include 1:1, 16:9, 9:16, and a few others. Resolution choices are 1K, 2K, and 4K.
Use it when you want clean, stylized work or when your prompt includes readable text. It accepts free-form references and uses them as visual inspiration.
Nano Banana Pro (Gemini Image 3 Pro)
Google's flagship image model. Pricing is 20 credits at 1K or 2K, and 40 credits at 4K. The display name in 1stUnit leads with the marketing name (Nano Banana Pro) and includes the technical name in parentheses, following Runway's convention.
This is the model to use for photoreal results, especially of people. It is also the model where the Char checkbox on reference cards matters most. When a reference is a character image, ticking Char tells the model to apply that character correctly. Untick it for environment, style, or lighting references.
Nano Banana 2 (Gemini 3.1 Flash Image)
The faster, lighter cousin of Nano Banana Pro. Pricing is the same, 20 credits at 1K and 2K, 40 credits at 4K. Use it when you want to iterate quickly on a look without spending the time on a full-quality Pro generation. The Char checkbox works the same way.
Video models
Gen 4.5
Runway's own video model. Pricing is 5 credits per second of output. Durations are typically 5 or 10 seconds.
Gen 4.5 expects a start frame as its primary input. Drop in an image and add a prompt, and the model animates outward from that frame. If you do not supply a start frame, the model falls back to text-to-video mode.
Gen 4.5 is the only model with a Fixed Seed toggle in Advanced Settings. Use it when you want to iterate on a prompt while keeping the underlying motion stable.
Seedance 2.0
An estimated 10 credits per second. Seedance has two input modes:
- Multi-reference. Free-form reference images that shape the look of the result.
- Keyframe. A first frame and an optional last frame for the model to interpolate between.
You pick the mode from the input tabs at the top of the reference section. Audio output is supported: toggle it on in the Takes row to get a soundtrack with the video.
Veo 3.1
Google's video model. Pricing is estimated at 12 credits per second. Veo accepts an optional start frame and optional end frame, or a text-only prompt if neither is supplied. Audio output is supported.
Veo tends to produce strong, clean video with good motion. It is a good default when you want a polished one-shot clip.
Why so many models
The point of having all six is not that one is best. Different models behave very differently on the same prompt and the same references. The same character image fed into Gen 4.5 and Veo 3.1 will produce noticeably different motion. The same prompt to GPT-Image-2 and Nano Banana Pro will produce different styles.
1stUnit treats this as a feature. The lineage of a take includes the model and the mode, so switching models always starts a new lineage and you can compare the same idea across models on the same shot.
Aspect ratios and resolutions
Each model has its own set of supported aspect ratios and resolutions. The New Run form only shows you valid combinations. If you change the aspect ratio and the resolution you had picked is no longer available, the form will reset it.
Image models accept 1K, 2K, and 4K with several aspect ratio choices. Video models have a fixed resolution per aspect ratio, so the resolution field is sometimes hidden.
A note on naming
You will sometimes see Runway products referred to as "Runway Gen 4.5" or "Runway Veo." 1stUnit deliberately does not prefix the model names with "Runway." All six models are accessed through Runway's platform, so the prefix is redundant. The display names you see in the app are the same brand names the model creators use.