Whats your opinion on forcing a user to use Landscape mode on mobile devices?

The more and more I use three.js, the more interactive they get.

I realized that I dont like designing in portrait mode, it destroys the experience since it’s intended to be viewed with widescreen.

On mobile devices that means that means enabling landscape mode.

What do you think about forcing them to enable landscape mode?

I feel like this might be a big issue in the future as more and more people start making 3d websites.

Let the DOM die, long live WebGL.

I’m not sure I understand your point. You already mentioned exactly what you should be considering: the user experience. And that is unique to your application.

If the websites you are creating are intended to be consumed in landscape, and you feel that you lose nothing from enforcing landscape, then enforce landscape.

This does not mean that portrait is useless. There are even cases where something designed for landscape should optionally support portrait, such as single-handed interaction, and accessibility considerations. But again, if it’s not part of your user experience story, then there’s no reason to include it.