This video shows you how to create your own fly through camera for viewing your architecture model! This is based on the Unity Starter Assets which can be found in here:
Third Person Controller:
https://assetstore.unity.com/packages/essentials/starter-assets-third-person-character-controller-196526
First Person Controller:
https://assetstore.unity.com/packages/essentials/starter-assets-first-person-character-controller-196525