How do I make a map with 3 different skyboxes?

[Halfblind]

I want to make a map with 3 different skyboxes for Zdoom and Zandronum. Depending on where you are in the map the skybox needs to change to create a different atmosphere. For example: I want one part of the map to be set in a floating platform in the clouds, the next segment to be set inside a computer and the third segment set in outer-space. I want to use the square box technique with the skybox viewpoint to give the skybox more depth. Is there a way to make the Skybox change such as using a replace texture script or is there an easier way to pull this off?

[MinerOfWorlds]

Just make three skybox areas or if you want all skies to change you can use change texture or (i think zdoom can do this) change the tags of the sectors you want the sky.

[Nevander]

In UDMF, it's very simple. You can keep the physical skybox the same and then create trigger lines or scripts to run to swap out the ceiling/floor texture at will using ACS. You will want to use ChangeCeiling and ChangeFloor respectively.

 

Alternatively, you could set up three different skybox "rooms" with the right textures, then instead of changing textures you could move the skybox viewpoint thing to mapspots inside the other skyboxes for an identical effect.

 

For Boom you have to do sky transfers or some other shenanigans. I don't map for Boom often so I couldn't explain further.

[Gez]

Read about SkyViewpoint and SkyPicker.

[Empyre]

In Doom-in-Hexen, and maybe also UDMF (I have not yet tried UDMF, but I plan to),  there is Static_Init that lets you use any texture as a sky. I've used it to make a map with several skies. That map also uses the method Gez mentioned.

[Halfblind]

Thank you everyone for the helpful advice. I'm going to tinker around a bit more to see what method works best for me.

[Empyre]

Now that I have read your question more closely, I see that Gez's answer fits better.