Roman Colosseum

Okay, so I’ve decided to try and model something that isn’t extremely simple, the Roman Colosseum. I want to make this model as close to scale as possible with information I can gather on the web which, for the most part, is very basic. The dimensions I have gotten so far are the outer wall (189x156x48) and the wall that protected the spectators (88x55x5). By the way, all measurements are in meters and I am just using the blender units for the scale. The outer wall has 80 pillars so each circle that I made has 80 verts.

I’ve just made the outer and inner walls’ base circles and have already run into a problem. Since the walls are elliptical, when I scale them the walls, which need to be the same length, have varying lengths.

Here is the perimeter of the inside wall:

Here is an example of my problem:

I’ve got only one potential solution to this problem that I have managed to come up with, but I’m not even sure if it will work. My solution is to get the average length of all of the edges and then apply that length to each of the 80 edges. I’m not sure that this would keep the elliptical shape. This would obviously take quite a long time and still may not be exact. This is why I am turning to these forums first.

I’m thinking that there may be a way to do this with the rotation tool, array modifier, and/or the screw modifier, though I have no idea how I would go about using them to achieve my goal. For all I know the solution to my problem can be as simple as enabling a option that I don’t know exists.

So my question is, is there a way to non uniformly scale a circle or rotate an edge to get a elliptical circle whose edges are all the same length?

As always, all help is appreciated.

Here’s a trick:
An ellipse is an oblique intersection of a cone. So, (1) add a cone and a circle; (2) set the snap tool (below the 3D view) to closest face with “project individual elements” enabled. (3) With the circle selected in edit mode, go to top view (Num7) and (4) scale the circle down and drag it sideways. (5) Disable the snap tool and rotate the circle to align it with the ground.

In the user preferences there is an addon called Add Mesh: Extra objects. One of those extra objects is a math function called XYZ Math Surface. I failed to make that tool plot the vertices at equal distances, but someone else might know some useful equations.

Well maybe you could use a curve in the shape of an ellipse and have an array applied to a one vertex mesh going along the curve. I’m not sure if this would work as I haven’t tried it but its worth a try.

I forgot the duplivert method. Here are columns evenly distributed along an ellipse. This method is non-intuitive to work with, but it actually did the trick this time.


Columns-on-ellipse-000.blend (314 KB)

I can’t seem to get this to work. I followed the steps exactly as you described them.

isn’t the colloseum shaped more like this?:

Nope. Wan’t sure at first but then looked it up on Google Maps and it is shaped the way I showed in my first post.

Based on the fact that I can’t find any hint on how to do this anywhere, I’m starting to believe this is an unsolvable problem.

Have you tried the Addon LoopTools with the “Space” command? That rearranges your verts so they are evenly spaced across the length of your arc.

  • Enable Loop tools
    File->Users Preferences->Addons->Mesh->LoopTools (enable it).
  • Select your eclipse and go into edit mode
  • Select all vertices
  • Hit “w” then select LoopTools->Space

While repeating Mats Halldin trick, i seem to get a bit distorted result.

Getting symmetrical ellipsis assumes deleting half of vertices and mirroring after if i’m right?
Anyhow, thanks for the tip. Newer used this before.
Math would involve a bit more: formulas

i did a colloseum model 2 years ago in 2.49
and it’s a difficult 3D model

the inside is almost like an ellipse but not the outside shape
the outsdie shape has an exact equation with something like 120 parameters!
so not easy to do it even on computer !

and also depends with which precision it is required to be done!
to get it inside 1 meter is very difficult !

and if you need to add the stairs and other architectural details it becomes more difficult

but you can model 1/4 of it and then apply the mirror modifier to get the whole shape!

and search forum there are at least 2 other threads on this subject !

one of the best way of modelling it is using the 4 ellipses equivalent for the colloseum!

i can get the dwg for this
let me know!


here are some dimensions for this building

Retractable roof
All around the top there were sockets for 240 wooden
beams which supported the awning (velarium)
poles up to 100 120 ft were used
Its coordinates are: latitude 41° 53’ 33" North, longitude 12° 29’ 31" East
The arches are 4.20 m. (13’9") wide and 7.05 m (23’1") high
on the ground floor;
on the upper floors they are only 6.45 m (21’2") high

Height floor Height Arch Width arch

1 Level Doric 34/10.36 23/7.01m 14/4.27m
2 Level Ionic 38/11.58 21 /6.4 m 14/4.27m
3 LevelCorinthian 37/11.28 21 /6.4 m 14/4.27m
4 Level 45/13.72m
podium wall = 15 ft / 4.57 m

underground wall 6 M tall

i’ll see what i can find for dwgs on this


here is a PDF file describing different ways to get the outside shape of this building

amphitheatre2.pdf (554 KB)

you can find it on the web if you search for it


you should change your title for this thread !

this PDF should give a good idea on how to make it with 4 ellipes which is the closest approximation i guess to make the outside shape of the wall!

but even with this it wont be inside 1 meter but closer may be to around 3 meters!

so read this PDF and let me know if you need more !


here are some of the link i used to find out the dimensions and details

have fun

I don’t know about changing the name of the thread but I am going to make a new one in the Works in Progress section.

I’ve kind of got a busy next two weeks so it may be a while before I get much into the modeling. I’m going to try and get a bunch of the reading and planning out of the way this week but I may not post any progress until next Monday. I plan on devoting that day to blender.

Thank you very much for the help and the load of info that you’ve provided. maybe you could use a curve in the shape of an ellipse and have an array applied to a one vertex mesh going along the curve.

well name would be easier for peoples looking for the colloseum when doing a search!

some of the PDF paper discuss the precision using ellipses to do the outside wall

so take the time to read these it will give you a better understanding of the challenge for this building
which as i said is one of the most difficult to model with precision in 3D!

now i have more data so if you need more let me know i can dig some more info!


Good point. Changing name now.

I haven’t started modeling because I am reading the PDF and quite a bit of the other information that you’ve provided, but I think that may be all I need for now.