Do wall pieces have to be rectangular in Ultimate Doom Builder (GZDoom Builder)?

I'm making maps for playing in GZDoom. What shapes do wall pieces have to be? Are they always square/rectangular or can I make a circular wall piece or other shapes?

Could I make a statue as a wall instead of as a decoration that isn't a wall?

From an overhead view, you can make whatever shapes you want. From a first person perspective, classic doom does not support any shape other than 'flat wall, floor, or ceiling'. No slopes, no ramps, certainly no arches. It also can't have floating geometry. You might be able to have a raised section of floor that sort of vaguely resembles a statue but that's it. It won't be able to have any overhanging sections.

If you're mapping in GZDoom's UDMF map format, you can have floating platforms, or in this case perhaps just have it display a straight up 3D model of a statue. But in the classic doom you only have 'lines' and 'sectors' that have a floor and ceiling height, and everything you see in a level is a result of that. So every wall is just a straight line, though lines can be arranged into a curve from a top down view. Essentially, other than height changes for the different sectors, anything you couldn't design in from a top down perspective isn't possible in Doom's mostly 2D engine.

Thanks. I'm making maps in Ultimate Doom Builder (former name of GZDoom Builder) for playing in GZDoom. You mentioned I can have a 3D model of a statue but is there any way to make complex shapes in Ultimate Doom Builder such as making a statue in the program instead of importing a 3D model?

Can I have circular wall stones instead of rectangular bricks, arches, slopes, etc?

Walls, floors and ceilings in Doom will always be essentially flat planes. But UDB does come with a variety of tools to let you manipulate those flat planes into more interesting shapes (presuming you mean when viewed horizontally, rather than the shape of the walls when viewed from above).

Go to Controls and look for "Visual Sloping" - you need to assign it to a hotkey. Then when in Visual mode, hit that key to allow you to grab the edge of sector floors and ceilings and slope them using the mouse wheel. There are other tools in UDB that let you make things like archways and circles, especially when combined with 3D Floors.

However, even with all these, the options are still limited in the grand scheme of things, and often require a lot of finessing and tweaking to make even quite rudimentary shapes beyond the standard rectangle of a floor/line/ceiling combination. 

If you are looking to make anything resembling complex shapes or natural terrain or anything like that, using a model (which is how modern engines work too) would make most sense. 

5 hours ago, Havok said:

I'm making maps for playing in GZDoom. What shapes do wall pieces have to be? Are they always square/rectangular or can I make a circular wall piece or other shapes?

If you are using GZDoom (DiHF or UDMF) then you can add 3D elements to a wall. Slope them in Visual Mode.

Or add circular elements with the Arch Tool