Re: Viewing in 3D

3D mode?
I think looking at your Sims up close?
Best way that I know is to hit ctrl+shift+tab, this will put the Sims 3 mouse option on. I don't know how the Sims 4 mouse works. 
Then you can move around by using the scroll wheel on your mouse. You can scroll to zoom in and hold and move to move the camera. 
In the options you can find a bit more that can help you.

I hope that is what you mean, if not, can you explain a bit more?