SceneViewer3D: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/SceneViewer3D - from package: mrpt-apps

You may install the required package with command apt-get install {package}

Error in other languages:
SceneViewer3D: bevel nie gevind nie
SceneViewer3D: comandă negăsită
SceneViewer3D: comando não encontrado
SceneViewer3D: commande introuvable
SceneViewer3D: command not found
SceneViewer3D: käsku ei ole
SceneViewer3D: không tìm thấy lệnh
SceneViewer3D: komanda nerasta
SceneViewer3D: Kommando nicht gefunden.
SceneViewer3D: kommandot finns inte
SceneViewer3D: komut yok
SceneViewer3D: nie znaleziono polecenia
SceneViewer3D: níor aimsíodh an t-ordú
SceneViewer3D: no se encontró la orden
SceneViewer3D: no s'ha trobat l'ordre
SceneViewer3D: opdracht niet gevonden
SceneViewer3D: parancs nem található
SceneViewer3D: perintah tidak ditemukan
SceneViewer3D: príkaz nenájdený
SceneViewer3D: příkaz nenalezen
SceneViewer3D: команда не найдена
SceneViewer3D: командата не е открита
SceneViewer3D: 命令找不到
SceneViewer3D: コマンドが見つかりません