Heya,

How can I do this? I wanna remove everything so i can do a clean install.

Thanks

Deleting the following should get you pretty close to a blank slate.

/Applications/Houdini
~/Library/Preferences/houdini
~/Library/Saved Application State/com.sidefx.*
~/Library/Application Support/Houdini
~/Library/Caches/Houdini*