# How to create a curved surface from a sharp edge?

Sorry for the basic question, but I have been working on this all morning and can get a basic curve but I keep falling short of what I really want.

I am in the process of making a urban street model (square sections), the first section went very quickly, just a street plane, 20x20cm curb, a sidewalk raised 20cm off the street.

When I moved on to the intersection section, street with 4 round corners with the curb then the sidewalk and be precise enough to have it tile up against the plain street section, I just ran into my modeling limitations.

1st I tried a Bezier Curve, a 20x20x20cm box with array and curve modifiers. I could only get it to work if I did it in the center of a new scene with a fixed count (fit curve did not work). If I applied the modifiers there was all this extra geometry and ending did not seem precise.

2nd I scrapped the curb and just extruded a vertex and used the spin tool for the curve, this worked but now I need to work the curb into the texture of the sidewalk. This worked and not sure if i'm just making things more complex then then need to be.

I wanted a 90 degree curve that fits in a 2mx2m square, one curve that is the 20cmx20cm curb and another right behind it that is the sidewalk.

• Could you perhaps try to draw a quick sketch of how this should look and upload the image, just basic lines at least in a paint program.. that might better help us visualize what you want. Commented Aug 20, 2013 at 21:10
• to get Fit curve to work, you can try applying the scale of the objects (Ctrl+A) Commented Aug 20, 2013 at 22:00

## 2 Answers

It is a bit difficult to visualize exactly what you actually want based on your wording of the problem but If I understand the problem correctly, what you want is a curved surface. You can achieve this by just bevelling a sharp edge,

You can take a sharp corner that connects at a 90° angle…

…and then bevel the edge using Ctrl + B and increase the segments to round it into a curved surface.

From what I can understand of your question, this is one way to do it. (as already mentioned by iKlsR)

if you don't need the curb and the sidewalk to be separate objects, you can get this by Beveling (CtrlB and use the mouse wheel to adjust the number of segments.):

If they do need to be separate objects, you can do this by

1. Add a circle and delete three quarters of it:

2. set your Pivot point to 3D cursor (.) , E extrude, and Sscale.

(instead of using the 3D cursor, you can also just use AltS to scale along the normals)

3. To create the sidewalk, duplicate the object (in object mode) and scale it down, then go into edit mode and press AltM > Merge at Cursor

• instead of extruding, i added 2 circles one at 2m and one at 2.4m, then added a face to the top Commented Aug 21, 2013 at 1:44
• @stephen it would be nice if you write an answer detailing your method. Commented Aug 21, 2013 at 4:33