michael thank u so much.with this tutorials i can fix a big category of rings
thanks again.if we dont talk again soon mary cristmas and happy new year
i hope u help me again
basilhs

Hi Basihs,

Here's a ring blank based roughly on the photo you supplied.

First I created a circle at 9mm Radius for the finger size.
I then created the ring Profile then used Rail Revolve as Michael has already suggested.
I then switched to the Right View & created two arcs then Joined them to form a closed shape.
While still in the Right View this new closed shape was Mirrored to the opposite side of the ring.
Still in Right View select the ring, click Boolean Merge & select the two closed shapes.
Delete the two sections that have now been cut from the ring.
Select the inside circle(finger size) & Extrude it with "both sides" checked.
Select the ring, click Boolean Difference & select the Extruded inner shape.
Select the ring again & click on all the outer edges of the band on both sides.
Click Fillet & enter 0.7mm.

That's it, but you'll still need to create the settings for the Diamonds & the centre stone.

Hope this helps, Colin

Hi Colin, I think I like your way better.

I was worried about making a straight cut like that possibly resulting in a blocky type shape. However, it works great when the straight cut is applied to a rounded base shape. The blocky type problem that I was worried about happens when you apply the straight cut to another straight-punched out (extruded) base object instead of a rounded base object.

And actually the hard edge that is introduced with your method is actually an advantage.

With your steps, you get this shape at one stage:



Which actually is nice because then filleting the outside edge lets you have a hard inside edge, and then a more tightly curved outside edge. That kind of seems like a more expected form around that area.

Actually with the sweep method you can get this style by first applying a wider chamfer along that single edge (the sweep method starts with just one edge around that finger hole), which will construct that straight bit for you, then round the outside edge of the straight part.

Anyway, I am still happy to have the sweep method documented above, it is always good to have more than one approach available for constructing things, sometimes when you want a particular kind of different style it can be easier to apply it in one method or the other.

A couple of small notes on your steps -

When you create the cutting pieces from the right-side view, it is ok if they are not closed, they can be open as long as their profiles cross the whole object and appear to fully divide it into 2 pieces.

You can also skip the extrusion of the circle - just select the circle curve as the cutting object in the Boolean difference. The boolean will do the equivalent of Extrude with "both sides" for you automatically.

billis - let me know if you need any additional illustrations for Colin's steps.

- Michael

Hi Michael,

<Hi Colin, I think I like your way better.>

The basic idea for doing a ring this way came from one of the guys on the 3dcadjewelry Forum.
This was his suggestion on how to make a Signet ring or School ring really simply.
I just figured I could use the same method to construct a ring similar to the photo.

<When you create the cutting pieces from the right-side view, it is ok if they are not closed, they can be open as long as their profiles cross the whole object and appear to fully divide it into 2 pieces.>

He's using Rhino, so I think that you might need to create a closed curve for it to work correctly in Rhino?
So I just started using the same basic construction method in MoI & it worked great, so never thought of doing it using an open curve?

<You can also skip the extrusion of the circle - just select the circle curve as the cutting object in the Boolean difference. The boolean will do the equivalent of Extrude with "both sides" for you automatically.>

Ahh!, Great Tip!! I've been so used to doing it the Extrude way that hadn't even thought of doing it like that?

regards Colin

Hi Colin,

> He's using Rhino, so I think that you might need to create a
> closed curve for it to work correctly in Rhino?

Yeah probably - Rhino isn't able to do booleans mixing solids and curves directly like MoI. So using Rhino you would probably make those closed, extrude them with "both sides", and then use boolean difference using the extrusions as cutters.

Rhino does have a separate "WireCut" command that will cut a solid by a curve (the curve can be open), but it seems to only work using a single curve cutter at one time, so you would need to repeat it 2 times to cut this object.

- Michael