# Rhino help - How to align surface edges to a closed curve?

Discussion in 'Boat Design' started by Guinther, Jul 29, 2011.

1. Joined: Jun 2011
Posts: 6
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Location: Brazil

### GuintherJunior Member

Hey guys,

I've been trying to model a concave shape with edges in different angles. Although I can make the concave shape, I cannot make its edges on the angles I need. I am sending the file in 3dm in attachment. The surface edges should match with the red line. If you have some time and like to be challenged, please help me to solve this.

Regards,

Guinther

#### Attached Files:

• ###### Alignborders.3dm
File size:
87.1 KB
Views:
509
2. Joined: May 2004
Posts: 5,372
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Location: Italy (Garda Lake) and Croatia (Istria)

### daiquiriEngineering and Design

Some things are geometrically impossible, unless you drop some of the constraints. This one is one of them. It is impossible to create a continuous concave surface from the edges arranged in the way these are arranged. The surface you have created shows it clearly. The planar (X-Y plane) shape of its borders is correct and consistent with the planar shape of the edge polyline, but the elevations are not because they just cannot be met with a simply concave surface.
Cheeers

3. Joined: Jun 2011
Posts: 6
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Location: Brazil

### GuintherJunior Member

I thought it was impossible... but I needed to check. Now I know it. However, starting the problem from its origin: I received this file (attachment) from a customer and I need to fill in the gap with the same context. I don't know what was the method used to model the other parts, but it seems almost impossible to model that gap with only this information... One of the methods I can imagine is to create a box and several spheres on top of it and then boolean difference. But then I would have to start from beginning...

Any other suggestions?

Thanks.

Cheers!

#### Attached Files:

• ###### SurfaceV1.3dm
File size:
828.6 KB
Views:
473

4. Joined: May 2004
Posts: 5,372
Likes: 256, Points: 93, Legacy Rep: 3380
Location: Italy (Garda Lake) and Croatia (Istria)

### daiquiriEngineering and Design

The problem is lacking some essential info. Without knowing what's around that gap and surface continuity constraints, you can do whatever you like to fill it. Even stuff like the one I've attached here.
Cheers

#### Attached Files:

• ###### Fillgap.3dm
File size:
195.8 KB
Views:
486
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