A groin vault is an intersection of two barrel vaults at right angles. A barrel vault , in its simplist form is just a tunnel with a round surface (half a barrel).

I am trying to model one of these and having a point of view problem. The method that I am using is to make two half barrels (9 CPs per arch) and and enough segments so that I can intersct each arch with the one on the crossing piece. I then manually line up the segments. I remove the un needed interior patches, draw in the crossing splines formed by the intersections and then weld the CPs at the intersecting points. In wireframe view the groin vault is perfect. In shaded view it is quite a mess. The joined edges are all formed of three point patches and render with a funny puffyness. Even texturing does not hide the anomalies. I cant seem to "see" another way to model this type of construct.

Anyone have a different angle that I can look at this problem from?

Bill

1-topview: create the following shape. highlight all cp's and press "P" on your keyboard to make them all peaks.

2-front or side view: extrude to give it some height.

3-top view: extrude outside cp's

4-top view: move the neceassary cp's to give it a squarish shape. select "corner" cp's before proceding

5-side or front view: translate the cp's down the y axis

6-select outside "peak" cp's and press the "O" key to make the corners arch


this is what you wanted i take it?


may not be the best method, but it seems to work pretty good. you can play with the handles if you want the arches more pronounced.

I made one in the WIP section here

I had a problem with my groin vault as well.

My doctor gave me some cream and it cleared up in about a week.

Vernon "!" Zehr

Thanks Guys. Hutch's method looks like it may come from the same basis as my original "crossed barrels" approach. I would be interested in hearing how you went about setting it up. NorthernBoy's technique is something that is utterly alien - very cool yet nothing I would have thought of. I am going to mess with both of these and see if I can broaden my horizions.

Vern - You are not nearly old enough to have a confirmed case of Vaulted Groin. I think that you should see a specialist.

Bill

I had to model a cathedral a while back for work, and my "Solution" to the groin vault problem was to model it in sections and use the equivalent of "Molding" over the seams. (Yes, it's a copout and a more talented hasher than myself could build the whole thing as one piece I'm sure) Not historically accurate perhaps, but aesthetically it worked very well for me. -might be worth playing around with building it in sections, after all cathedrals weren't made out of one solid piece of stone :-P

Here's my solution for a groin vault. I haven't checked out everyone else's solution, but I will!

Basically, I modeled one side of the vault as a modular piece. To get the other side of the vault, just flip it and save as a different name. Then I modeled the roof separately and assembled them in the chor.

This way you can create a series of vaults as long as you want with very little (relative) extra work.

http://www.holmesbryant.com/misc/groin_vault_and_roof.zip

Here's a picture of my finished cathedral complete with a series of groin vaults extending all the way down the nave. The groin vaults are somewhat disguised because through most of the nave, the cross sections end in walls instead of extending into hallways, but they could just as easily have been hallways instead of walls.
http://www.holmesbryant.com/digital-still/cathedral1.html

Holmes

I came up with a slightly different way of achieving it. Basically, my set was lined with columns along the walls, each of which had a curved frustum on top of it. The frustum looked like this:



The entire thing is nine patches: the four large ones on the sides, and four skinny ones in between them to bevel the corners a bit. The ninth, on top, was to make a "double wall" so I could have a volumetric light shining in from outside. (There is also a bunch of dangling splines hanging off, so I could achieve the curvature.)

They were arranged so that the outermost edges all touched, resulting in a ceiling which looked like this:



Here's a zip file containing the ceiling segment, if you're interested.

[Edit] - fixed the URL. D'oh!

It is cool to see how many different solutions people come up with for the same problem. This almost makes me want to model a cathedral and I hate church!

Hutch - Actually, I am not working toward a cathedral but a palace inspired by Ottoman (Turkish) architecture. The vaulting is very similar but the details (and the domes - lots of domes) make it distinct from a gothic cathedral. I'll put up some WIPs next week.

Bill

Holmes & TJ;

Indeed. Seamless cathedrals are a thing not found in nature

The problem I was having is that when I constructed the quarter section of the vault, I was not seeing any other unit to build except a dead-on slice of the half barrel (looked like a nib for a calligraphy pen). My technique then gave me a versatile vault segment with puffy artifacts making a sawblade pattern at the seams.

I think the solutions that have been posted have helped me to see alternate methods to what was my madness.

Thanks a bunch.

Looking good and thanks for the files.....the learning process goes on...smile.

Mike C