How do I create this 3D object?

Constructs 3D shapes are (intentionally) relatively limited. I don't think an Arch like that will be possible with vanilla Construct.

You can use 3rd party plugins

kindeyegames.itch.io/c3-3dobject-alpha

Thank you for your answer. I had actually seen this plug-in before. I'll look at it more closely

You can do a lot with mesh distorts. Here's a way to generate an arch mesh. There's just no end faces although those could be added.

dropbox.com/scl/fi/5a23jevq10r3kqzapd7a9/arch_3dmesh.c3p

In a similar fashion it's possible to take any polyline and revolve it around an axis, or extrude it along a path to make a 3d shape from one distort mesh. So spheres, cylinders, cones, torii, screws, ... etc, could be made. Actually with some creativity you can make all kinds of 3d shapes with distort meshes.

Of course R0j0 can just casually do it...

Actually with some creativity you can make all kinds of 3d shapes with distort meshes.

I don't think creativity is the limiting factor here. :D It's certainly impressive but I personally couldn't imagine working with it other than maybe a background element. It's just some obscure math magic, and sure, everything is but I don't have to understand most of it. I still don't know what cos() or sin() actually do under the hood, I just know when to use it and what result I can expect.

I guess the use of the trig functions look obscure. If it helps this is the formula I’m using that uses trig. All it does is rotate an xy point around 0,0 by some angle.

NewX =x*cos(a)-y*sin(a)

NewY =x*sin(a)+y*cos(a)

The cool thing about it is you can rotate other ways too such as xz, just replace the y with z in the formulas.

This is all I’m using that equation for:

// make a circle

Vector(radius1, 0, 0)

RotateXY(b)

//Then rotate the circle in an arc to make the rings.

Move(-radius1, 0, 0)

RotateXZ(a)

The equation I used is just all that combined and simplified. All the equations I ever use in my examples are like that, a combination of simple steps combined and simplified.

Impressive as usual R0J0hound.

Indeed with math you can do anything, you still have to have the notions all this time.

Thank you very much the trigo master ^^