> For the complete documentation index, see [llms.txt](https://docs.atlas.design/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.atlas.design/atlas-ai-studio-overview/node-index/input-nodes.md).
# Input Nodes
Input Nodes are how source content enters an Atlas workflow. Every pipeline starts with one or more input nodes: a reference image, a text prompt, a parameter value, a PDF design document, a 3D mesh to refine, or an audio clip to process. The platform supports inputs across every content type Atlas operates on.
## When to use input nodes
Use input nodes whenever you need to pass material from outside the workflow into the graph. Common patterns:
* **Reference-driven generation.** Drop a concept art image into an Input Image node to drive style or composition in downstream generation nodes.
* **Parameter exposure.** Use Input Number or Input Boolean nodes to expose tunable settings (seeds, dimensions, toggles) that the workflow operator can adjust per run.
* **Document-driven workflows.** Feed game design documents (GDDs) or art bibles via Input PDF, then extract text and images downstream for use in generation prompts.
* **3D refinement.** Bring an existing mesh into the workflow via Input Mesh to retopologize, retexture, or rig it without regenerating geometry.
* **Animation and motion.** Use Input Mixamo Animation to bring FBX animation clips for retargeting onto generated characters.
### Input Boolean
* Lets you manually toggle a simple Yes/No (True/False) value.
### Input Number
* Provides a way to manually input / control specific numerical values, for example the 'seed' of an AI generation.
### Input Text
* Allows you to manually enter text strings for use in your graph. Most AI models on the platform have reasoning capabilities and are therefore able to handle extensive and or complex prompts.
### Input Image
* Used for manually uploading or selecting a single image file from your device.
### Input Images
* Allows for manual uploading and management of a collection of multiple images treated as a list.
### Input Mesh
* Enables the manual upload or selection of 3D model (mesh) files in GLB format.
### Input PDF
* Provides a field to upload and process PDF documents.
### Input Video
* Allows you to upload or select video files from your computer to add to your pipeline.
### Input Audio
Supplies audio files into Atlas workflows for processing, analysis, or transformation. Accepts standard audio formats and passes the file to downstream nodes that support audio input.
* Upload field accepts common audio formats (MP3, WAV, OGG, FLAC).
* Output provides the audio file reference for connection to audio-processing or transcription nodes.
* File size and duration limits depend on the backend receiving the audio.
* Retains original audio properties (sample rate, channels, bit depth) unless modified by downstream processing.
* Useful for providing voice-over recordings, background music stems, or sound effect samples for analysis, transcription, or AI-driven remixing in game audio pipelines.
### Input Maximo Animation
Supplies pre-downloaded animation files from the Mixamo library into Atlas workflows for rigging, retargeting, or motion editing. Designed to work with FBX animation data exported from Mixamo's web platform.
* Upload field accepts FBX files containing skeletal animation data.
* Output provides the animation reference for connection to retargeting, blending, or character rigging nodes.
* Does not fetch animations directly from Mixamo; files must be downloaded externally and uploaded through this node.
* Preserves animation clip properties including keyframe timing, bone hierarchy, and motion curves.
* Compatible with humanoid rigs and generic skeletal structures depending on the downstream retargeting or processing node.
* Useful for rapidly prototyping NPC locomotion cycles, combat animations, or cutscene performances using Mixamo's motion-capture library without manual keyframing.
## Common pitfalls
* **Wrong file format.** Each input type has specific supported formats: Input Mesh expects GLB, Input Mixamo Animation expects FBX, Input Audio expects MP3/WAV/OGG/FLAC. Uploading the wrong format produces silent failures downstream.
* **Hard-coding values that should be parameters.** When a workflow will be exported as an API, expose anything callers might want to vary (seeds, prompts, dimensions) as separate input nodes. Hard-coded constants become unchangeable in the deployed API.
* **Skipping reference image quality.** Input Image accepts anything, but downstream nodes (Image to 3D, Multi-view to 3D, text-conditioned image generators) work best with clean, isolated subjects on neutral backgrounds. Process noisy inputs through 2D Post Processing nodes before feeding generation nodes.
* **Forgetting Input Images (plural) vs Input Image.** Multi-view 3D generation and batch processing nodes expect an array of images. Use Input Images (or build an array via Create Image List in [Utility Nodes](/atlas-ai-studio-overview/node-index/utility-nodes.md)) rather than chaining multiple single Input Image nodes.
## Related nodes
* [Utility Nodes](/atlas-ai-studio-overview/node-index/utility-nodes.md) — array management, text processing, document extraction, structured output. Useful for transforming inputs before feeding them to generation nodes.
* [Image Nodes](/atlas-ai-studio-overview/node-index/image-nodes.md) — generation and editing nodes that typically consume Input Image or Input Images.
* [Mesh Nodes](/atlas-ai-studio-overview/node-index/mesh-nodes.md) — 3D generation and processing nodes that consume Input Image (for image-to-3D) or Input Mesh (for refinement).
* [API Nodes](/atlas-ai-studio-overview/node-index/api-nodes.md) — the corresponding "external" version of input nodes for workflows exported as APIs. Replace Input nodes with API Input nodes when preparing a workflow for external execution.
## Frequently asked questions
**What's the difference between Input Image and Input Images?**
Input Image accepts a single image file. Input Images accepts a collection (array) of multiple images treated as a list. Use Input Images when feeding multi-view 3D nodes, batch processors, or comparison workflows.
**Which 3D file formats can I upload via Input Mesh?**
GLB is the supported format. Convert other formats (FBX, OBJ, USDZ) to GLB before uploading.
**Can I upload videos directly?**
Yes, via the Input Video node. Standard video formats are supported. For text-to-video workflows, you'll also want to look at [Video Nodes](/atlas-ai-studio-overview/node-index/video-nodes.md) for generation-side capabilities.
**How do I expose input values as parameters when exporting a workflow as an API?**
Replace each Input node with the corresponding API Input node before exporting. For example: Input Text becomes API Input Text. API Input nodes let external callers send values into the workflow at execution time. See [API Nodes](/atlas-ai-studio-overview/node-index/api-nodes.md) for the full export process.
**Can I fetch Mixamo animations directly from the Mixamo platform?**
No. The Input Mixamo Animation node accepts FBX files exported from Mixamo's web platform; it does not fetch animations directly. Download from Mixamo first, then upload.
**What's the file size limit for inputs?**
Limits depend on the downstream node consuming the input. Mesh files for retopology have different practical limits than image files for generation. If an upload fails, the most common cause is file size; reduce resolution or polycount upstream before retrying.
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