Understand the Sentis workflow

To use Sentis to run a neural network in Unity, follow these steps:

  1. Use the Unity.Sentis namespace.
  2. Load a neural network model file.
  3. Create input for the model.
  4. Create an inference engine (a worker).
  5. Run the model with the input to infer a result.
  6. Get the result.
Tip

Use the Workflow example to understand the workflow applied to a simple example.

Use the Unity.Sentis namespace

To use the Unity.Sentis namespace, add the following to the top of your script:

using Unity.Sentis;

Load a model

Sentis can import model files in Open Neural Network Exchange (ONNX) format. To load a model, follow these steps:

  1. Export a model to ONNX format from a machine learning framework, or download an ONNX model from the internet.

  2. Add the model file to the Assets folder of the Project window.

  3. Create a runtime model in your script:

    ModelAsset modelAsset = Resources.Load("model-file-in-assets-folder") as ModelAsset;
runtimeModel = ModelLoader.Load(modelAsset);

Refer to Import a model file for more information.

Create input for the model

Use the Tensor API to create a tensor with data for the model. You can convert an array or a texture to a tensor. For example:

// Convert a texture to a tensor
Texture2D inputTexture = Resources.Load("image-file") as Texture2D;
TensorFloat inputTensor = TextureConverter.ToTensor(inputTexture);

Refer to Create input for a model for more information.

Create an inference engine (a worker)

In Sentis, a worker is the inference engine. You create a worker to break down the model into executable tasks, run the tasks on the GPU or CPU, and output the result.

For example, the following creates a worker that runs on the GPU using Sentis compute shaders:

IWorker worker = WorkerFactory.CreateWorker(BackendType.GPUCompute, runtimeModel);

Refer to Create an engine for more information.

Run the model

To run the model, use the Execute method of the worker object with the input tensor.

worker.Execute(inputTensor);

Refer to Run a model for more information.

Get the output

You can use methods such as PeekOutput to get the output data from the model. For example:

TensorFloat outputTensor = worker.PeekOutput() as TensorFloat;

Refer to Get output from a model for more information.

Additional resources