Benefits of portals vs 3d floors?

[gwHero]

So I understood the skybox viewpoint I'm using in my mod is technically an implementation of a portal. It's a great feature and the benefits are clear to me.

Now "regular" portals is another story. Searching for examples I found a clean one in this thread viewtopic.php?f=3&t=52118#p909587.

Without the knowledge of portals I personally would have created this situation with 3d floors. 3d floors is something I'm used too; I once created a six storey building in a previous mod without much pain. Okay, I had to create a lot of control sectors but now I could even reduce these numbers significantly since we nowadays can define multiple tags per sector.

So could someone explain what the benefits of portals are compared to 3d floors? Do they offer more functionality that I don't see yet?

[Gez]

Yes, both portals and 3D floors have their own benefits and drawbacks.

For something like building with several stacked stories, portals would be more useful. Consider that if they are stacked with 3D floors, then all floors will technically share the same sectors. What this means is that

• Weapon "sound" is heard across all floors by monster AI, which you might not want.
• The 2D-nature of the BSP means that everything vertically in the field of view will be processed by the renderer even if it ends up not being visible because it is in a different floor
• The automap and editor can quickly become confusing if each floor has a different floor plan.
• Having things like rounded archways require sloped 3D floors which are a lot harder to set up than normal slopes.

[gwHero]

thanks Gez for pointing out aspects I hadn't thought off.
What you say about 3d slopes makes me thinking about combinations of portals and slopes that would offer more possibilities.
I think I will start some experiments