Livre  0.2.0
Livre ( Large-scale interactive volume rendering engine )
User Guide

Table of Contents

  1. General Information
    1. Overview
  2. Installation
    1. Setup
  3. Getting Started
    1. Volume pre-processing tools
    2. Livre
    3. Transfer function editor


General Information

Overview

Livre is a out-of-core volume rendering engine depending Equalizer and OpenGL for rendering, and Tuvok library for data management.

Installation

Setup

Livre, currently doesn't have Ubuntu or Redhat packages. It should be build from the source code at github.(The compiler should support the C++11 - minimum g++ 4.6 - to compile the project because of the Tuvok library dependency). The basic building procedure is as below:

$ git clone https://github.com/BlueBrain/Livre.git
$ cd Livre
$ mkdir build
$ cd build
$ cmake ..
$ make
$ make install

The above commands will fetch the necessary packages and build the dependencies, and install the executables and libraries.

After a successful build and installation, the following executables will be available:

  • livre ( The command line render application )
  • livreGUI ( Transfer function editor )
  • TuvokDataConverter ( TuvokDataConverter )

Getting Started

Volume pre-processing tools

The volumetric data should be pre-processed in order to visualize in Livre. More information about the pipeline of preprocessing can be found at Tuvok Volume Data Generation tools page.

Livre

The volume renderer is executed through the command line. To test if the volume renderer is working or not, you can simply execute :

livre --volume mem://1024,1024,1024,32

which will render an in memory test volume data structure. Here 1024,1024 and 1024 are the width, height and length of the volume in voxels, respectively. 32 is the block size and "mem://" is the scheme to generate in memory volume. You should be getting an image like below:

livre.png
Livre

The command line parameters are shown below:

Application Parameters
--volume URL
Volume Renderer Parameters
--sse arg (=1) Screen space error
--datacachemem arg (=1024) Maximum data cache memory (MB)
--texturecachemem arg (=3072) Maximum texture cache memory (MB)
--texturedatacachemem arg (=8192) Maximum texture data cache memory (MB)
--maxrendermem arg (=1536) Maximum render memory

The important parameters are :

  • "--volume" ( URL of the volume )
  • "--sse" ( Quality of the rendering, the lower the value, the higher the quality. If value is 1, 1 pixel is 1 voxel, for lower quality values should be larger than 1 )

Transfer function editor

Transfer function editor helps the users to attach different colors and opacities to voxel values. The "livreGUI" is the main application for editing the transfer function. It can connect the "livre "application remotely and can modify the colors. Each color channel can be modified separately. The starting dialog is as below:

MainWindow.png
Main Window

For connection, hit the connect button and enter the hostname where "livre" application is running.

Connection.png
Connection Dialog

After successfull connection, you can open the transfer function editor. In the plot area x axis represents the values of voxel and the y axis represents the opacity values. Each color channel can be modified seperately by selecting the channel from the color channels.

TransferFunctionEditor.png
Transfer Function Editor