Tapered soft edge - Did it wrong? How would I do it using SubD?

I use a combination of Rhino and Zbrush for conceptual design work, but only occasionally so my skill are VERY limited…

I needed to create a sheepskin rug outline shape in Rhino to drape over a chair in Zbrush. The shape is fine (very simple) but I’m struggling with getting a tapered soft edge (see in the attached pic). I started by drawing a curve in the shape of the rug, then made into a planar Srf and extruded up. I then deleted the sides and used Blend Surface. This gave the result in the pic which I then used Quad Remesh on to give something I could import in Zbrush (see pic).

Problem is that the curve/edge blend isnt even all the way around so when I rebuild the curve in Zbrush it gives slightly wonky edges. Is there a better way of doing this in Rhino?

Also, is there a way of doing this with SUB D? I tried but cannot for the life of me figure out how to drag an edge loop outwards in all directions with a shape like this? Doing this would be so much easier.

Hi Kris - please post a Rhino file with the surfaces.


Hi Pascal, I’ve attached the file here. You can see the one shape like on the image posted above and the others are test pieces. I tried making a sub D mesh from the planar surface with no edge fillet but it doesn’t come out right for some reason…

Hide Rug Test.3dm (4.3 MB)

Hi Kris - is the attached on the right track?

Hide Rug Test_Maybe.3dm (2.6 MB)


It’s certainly close, but uneven along the edges, most likely because of the messy mesh I gave you. I’ve attached another file which should illustrate it better. There is a surface with a nice edge profile that I’d like to replicate in SubD as it isn’t even all around in the nurbs version. Next to the nurbs model is a sub D of a different shape. I figured you could just ‘pull’ out the middle edge loop and then de-crease the top and bottom edge. But I’ve no idea how to pull that loop out?

Pascal.3dm (2.6 MB)

Hi Kris - messy as in this type of thing?

That is due to my cheap scale2d way of getting a quick result…

Pascal_Maybe.3dm (2.5 MB)


Yea that and also because the mesh points aren’t perfectally vertical between the top and bottom surface. Thats why I sent across another model. Is it possible to pull an edge loop out in all directions in a shape like this in SubD?

Hi Kris - I attached another attempt above - I removed the extra loops of edges on the vertical sides, leaving only the middle one.

I turned on control points (F10 key) for the subD and selected that loop of points (double click on a control polygon in that direction)


Then MoveUVN those points in the N direction, I had the scale at 10.


Then RemoveCrease



That’s EXACTLY what I was looking to do. You’re a legend!!! Just out of interest how would you have done the same thing in nurbs? The blend surface command I tried worked OK but not perfectly

Hi Kris - what is your reservation about the BlendSrf in your example ? It looked OK to me…


It looked great but I think there were quite a few variations going around the perimeter. It became more obvious when converted to a mesh and the taper was thicker/thinner in areas. It’s visible in nurbs as well but very subtle.