> ## Documentation Index
> Fetch the complete documentation index at: https://docs.spine.altician.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Grab & Deform

> Tissue manipulation in the virtual endoscope

## Overview

The Grab & Deform feature allows you to push or pull on soft tissue structures, such as the spinal canal or ligaments. It uses a viscoelastic physics model for illustrative tissue behavior.

## Activation

Toggle **Grab** mode in the endoscope controls panel.

## Usage

With grab mode active:

1. **Click and drag** on a mesh surface to deform it.
2. The tissue responds with **viscoelastic spring-back** behavior.
3. A **J-curve nonlinear** response provides illustrative tissue behavior.

## Constraints

* Deformation is limited to a maximum of **10 mm** displacement.
* **Vertebral bodies act as collision boundaries** — tissue cannot be pushed through bone.
* Only soft tissue structures (canal, ligaments) respond to deformation; bone structures are rigid.