How to download and setup voreen
Open terminal and run command
                                            git clone https://github.com/voreen-project/voreen.git
                                        
                                        git clone is used to create a copy or clone of voreen repositories.
                                        You pass git clone a repository URL. it supports a few different network protocols and corresponding URL formats.
Also you may download zip file with voreen https://github.com/voreen-project/voreen/archive/master.zip
Or simply clone voreen with SSH
                                            [email protected]:voreen-project/voreen.git                                    
                                    If you have some problems with voreen
You may open issue on voreen support forum (system) here: https://github.com/voreen-project/voreen/issuesSimilar to voreen repositories
Here you may see voreen alternatives and analogs
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