Help forming the arm of a chair

[joearm89]

Hi Mcneel forum.

I’m trying to shape the arm of a chair

I made the model by creating cross sectional curves and then using the sweep1 command then cutting away at the resulting surfaces. I then used patch to create some of the sides of the form.

Here’s the model but there are a few issues:
JA armrest.3dm (5.5 MB)

1. I am having trouble where the shape widens because the level of the edge of the shape in this image needs to be lower like the red line:
   

   

2. I am trying to get a slow transition from a sharp edge (1mm radius) at the front of the form to a soft edge (5mm radius) at the back of the form
   

   

3. This edge should also have a smooth transition from radius edge at the back to sharp edge at the left
   

   

4. Generally I am trying to make the form concave at the back where the elbow of the arm sits and convex at the front where the hand would sit. With that said, the edge closer to the user needs to be lower than the outside edge of the arm (far edge in this image)
   

   

Obviously I need to use some slightly more advanced techniques to achieve the results I am looking for.

Any help would be greatly appreciated.

Thanks

J

[theoutside (Kyle Houchens)]

this is a good candidate for subd.

that would allow you to have a lot of control over the sculpting of the surface.

if you have not done any subd modeling, I’d start here-

Rhino 8 - Your 1st SubD Model!

and make sure and watch this one too-

Rhino 7- SubD, Rule of Three

if you need the best of both worlds (the sharpness and precision of nurbs and the sculpting of subd) you can model the sides and bottom in nurbs, then overbuild a sub surface, convert it to nurbs and then do your fillets and transitions.

[martinsiegrist]

I’m curious, how are you planning on having this piece produced?