I have installed the Autodesk Revit 2023.1 Update that is supposed to include the Twinmotion visualization application, but when I click the View > Presentation > Twinmotion > Open in Twinmotion in the ribbon, Revit gives me the error "Twinmotion application not installed":
The Epic Games' Twinmotion app itself is not part of the Revit 2023.1 update and requires a separate installation (and a 16GB download).
You can download this app from your Autodesk Account, from the "All Products and Services" list (if your account is managed by your company's subscription administrator, he/she must first assign this product to you):
Clicking on "Access" will take you to Twinmotion.com page where, after confirming the license terms (EULA), you will see a button to download a ZIP archive with the installation (16GB). This can be then downloaded, unzipped and installed with the installer (.MSI). Revit must not be running during the installation.
Then start Revit and repeat opening the scene (project) in Twinmotion.