[doc] Update README and clean up (#105)

* [git] Remove unused scene directory and NeedleBend from the scenes directory

* [doc] Add a README with doc and description

* [doc] Add usage example in README

* [doc] Move Usage to the end of README

Author: th-skam

README.md

@@ -1,6 +1,115 @@
+# Collision Algorithm for Needle Insertion - SOFA Plugin
+
+[![Support](https://img.shields.io/badge/support-on_GitHub_Discussions-blue.svg)](https://github.com/sofa-framework/sofa/discussions/)
+[![Discord](https://img.shields.io/badge/chat-on_Discord-darkred.svg)](https://discord.gg/G63t3a8Ra6)
+[![Contact](https://img.shields.io/badge/contact-on_website-orange.svg)](https://infinytech3d.com/)
+[![Support us](https://img.shields.io/badge/support_us-on_Github_Sponsor-purple.svg)](https://github.com/sponsors/InfinyTech3D)
+
 ## Description
-This is a SOFA plugin (https://github.com/sofa-framework/sofa) that provides a customized collision pipeline, specifically designed to support needle insertion simulations. 
-Works in conjunction with https://github.com/InfinyTech3D/ConstraintGeometry.
+This SOFA plugin (https://github.com/sofa-framework/sofa) provides a customized collision 
+pipeline, designed specifically for needle insertion simulations. 
+
+When used together with SOFA haptic device plugins, the system offers tactile feedback 
+for puncture resistance, release and friction during insertion and retraction.
+
+This plugin has also been integrated in Unity via the [`SOFAUnity`](https://github.com/InfinyTech3D/SofaUnity)
+plugin by InfinyTech3D for an enhanced simulation experience. Contact us for more information!
+
+## Features
+
+- Proximity detection between the needle and tissue mesh primitives
+- Needle simulation phases: puncture, insertion, retraction
+- Constraint-based needle simulation during the 3 phases
+- Support for haptic feedback such as resistance during puncture and friction during insertion
+- Compatible with SOFA-Unity integration for real-time interactive applications
+
+## Installation and Setup
+
+First review the official SOFA documentation for building and registering SOFA plugins
+https://sofa-framework.github.io/doc/plugins/build-a-plugin-from-sources/
+
+### Build Steps
+
+- Set up your `external_directories` directory (described in the SOFA documentation link above)
+- Clone this repository into your `external_directories` directory:
+    - git clone https://github.com/InfinyTech3D/CollisionAlgorithm.git
+- Register the path to your local `CollisionAlgorithm` repository in the CMakeLists.txt file located inside your `external_directories` directory
+```sofa_add_subdirectory(plugin CollisionAlgorithm CollisionAlgorithm)```
+- Set `SOFA_EXTERNAL_DIRECTORIES` variable (preferably using CMake GUI) to point to your `external_directories` directory
+- Configure and generate the SOFA solution using CMake
+- Compile SOFA solution (the plugin will be compiled as well)
+
+> [!IMPORTANT]
+> In order to use the plugin, make sure that you have also built the downstream 
+[`ConstraintGeometry`](https://github.com/InfinyTech3D/ConstraintGeometry) plugin.
+
+Supported SOFA version: v25.06 and above
+
+## Architecture
+
+- doc:
+    - Documentation and screenshots of the examples
+- scenes:
+    - Various simple demo scenes
+- src/CollisionAlgorithm:
+    - source code of the insertion algorithm SOFA component and supporting collision pipeline classes
+- regression:
+    - Files for automated regression testing in alignment with SOFA's testing framework
+
+## Usage
+
+- To use the plugin, include the `CollisionAlgorithm` plugin in your SOFA .xml scene file.
+
+``` <RequiredPlugin name=`CollisionAlgorithm`/> ```
+- Add the `CollisionLoop` component in the root node of your scene.
+
+``` 
+<FreeMotionAnimationLoop/>
+<ProjectedGaussSeidelConstraintSolver tolerance='<your tolerance>' maxIt='<maximum solver iterations>' />
+<CollisionLoop/>
+
+<CollisionPipeline/>
+<BruteForceBroadPhase/>
+<BVHNarrowPhase/>
+<CollisionResponse name='response' response='FrictionContactConstraint'/>
+<LocalMinDistance name='proximity' alarmDistance='0.2' contactDistance='0.08'/>
+``` 
+This component substitutes the default `CollisionPipeline` and manages the needle insertion algorithm.
+However, the two components can co-exist, allowing users to mix the standard collision detection/constraint resolution pipelines of SOFA.
+
+- Create a node to represent the needle and additional nodes for the needle tip and shaft geometries
+Refer to the `scenes/NeedleInsertion.xml` example scene for guidance.
+
+- Add an `InsertionAlgorithm` component inside the needle node as shown below.
+```
+<Node name='needleInsertion'>
+    <InsertionAlgorithm name='algorithm'
+        tipGeom='@<path to needle tip geometry component>'
+        shaftGeom='@<path to needle shaft geometry component>'
+        surfGeom='@<path to tissue surface geometry component>'
+        volGeom='@<path to tissue volume geometry component>'
+        punctureForceThreshold='<float>'
+        tipDistThreshold='<float>'
+    />
+    <DistanceFilter algo='@algorithm' distance='<float>'/>
+    <SecondDirection name='punctureDirection' 
+        handler='@<path to the tissue surface triangle handler>'
+    />
+    <ConstraintUnilateral name='punctureConstraint' 
+        input='@algoSkin.collisionOutput' 
+        directions='@punctureDirection' 
+        mu='<float>'
+    />
+    <FirstDirection name='bindDirection' handler='@<path to the normal handler of the needle beam'/>
+    <ConstraintInsertion name='insertionConstraint' 
+        input='@algorithm.insertionOutput' 
+        directions='@bindDirection' 
+        frictionCoeff='<float>' 
+    />
+</Node>
+```
 
 ## Acknowledgments
-This project builds upon the original repository from [ICube Laboratory, University of Strasbourg](https://icube.unistra.fr/en/) and extends it with a needle insertion algorithm and additional functionality.
+This project builds upon the original repository from 
+[ICube Laboratory, University of Strasbourg](https://icube.unistra.fr/en/) 
+and extends it with a needle insertion algorithm and additional functionality.