---
id: design-considerations
title: Design Considerations
summary: Overview of the fundamental architecture and interfaces in Cornerstone3D, including the rendering system built on vtk.js and the tools library with event handling
---

## High level design considerations

These libraries expand upon and update the interfaces `cornerstone.js` provided
to better support volume rendering, 3D aware tools, and PET images support. These
interfaces and functionality are broadly identified as:

- Rendering / Renderer
- Image Loading / Image Loader
- Metadata Provider
- Tools

`@cornerstonejs/core` is a "rendering" library built on top of `vtk.js`.
which leverages `cornerstone`'s existing plumbing to integrate with image loaders and metadata providers.

This repository's `@cornerstonejs/tools` is a "tools" library that, once initialized, will listen for custom events emitted by `@cornerstonejs/core`. Please note, the event naming and handling overlaps the events and event handling in the `cornerstone-tools` library. If you attempt to use `cornerstone-tools` in tandem, you will likely encounter issues. As this is a possible use case, please don't hesitate to report any issues and propose potential solutions.