As the title said , How did they do it? I saw many people have this fancy Viewport GUI that shows a model rotating. I tried many things , but it just wouldn't work. The Viewport's Camera simply doesn't exist in Client-Side , So I can't do Camera CFrame :(
You can try to do this, Place it inside a screenGui with a ViewportFrame in it:
local cam1 = instance.new("Camera) cam1.Parent = workspace cam1.CFrame = workspace.cam1Point.CFrame script.Parent.ViewportFrame.CurrentCamera = cam1
Then imagine that the cam1Point object is a camera, Try to then position your objects around that point/camera. Remember to place the object inside the viewportFrame once you're done.