Fri, 02/18/2011 - 12:18

Forums:

Hi,

I want to create a middle face between two faces and I have

no idea how to do this with Open CASCADE.

Is there a function in Open CASCADE to calculate a mid face?

Or does anybody know helpful routines to do this?

Thanks,

Nicolas

Fri, 02/18/2011 - 15:06

What do you mean by "middle face"? Do you have a gap between 2 faces you want to fill?

Fri, 02/18/2011 - 18:55

Hi Fabian,

No, I don't want to fill a gap between 2 faces.

That would be quite easy, I think.

Consider the simple case of 2 parallel curves, then the middle

curve would run parallely in between the 2 curves.

The analogon is to create a middle face for 2 opposite faces.

CU

Nicolas

Fri, 02/18/2011 - 19:22

The term "parallel curves" makes only sense for lines. So are you talking about planes? If that is the case, you could use

GC_MakePlane (const gp_Pln &Pln, const Standard_Real Dist)

Make a Plane from Geom parallel to another

Pln at the distance

If you're talking about 2 surfaces in general (not planes particularly), I'm still not sure what you mean by "parallel". An Interpolation between the two faces?

Fri, 02/18/2011 - 19:25

By interpolation, I mean that every point on the "mid surface" is exactly at half the distance between 2 points of the other 2 surfaces...which still leaves open the question how to select those two points. Via intersecting the surfaces along the z direction or along one surface's local normal?

Mon, 02/21/2011 - 19:10

Yes, that's what I mean. The question how to select those two points is what makes it difficult,

because the surfaces need not be parallel and they can be of different shape.

I have attached a jpeg picture that shows the mid surface created from the outer ones using

an algorithm that I implemented for a preprocessor.

Hopefully it makes the problem easier to understand.

I want to do this with Open CASCADE (and more clever) now.

Fri, 02/18/2011 - 21:00

Can you please provide a pictorial representation of what it is? I am asking this because the problem seems to be interesting but I am not able to visualize what exactly you mean.

Mon, 02/21/2011 - 19:12

Hi, I have attached a jpeg-file to visualize the problem. The picture shows the mid surface

created from the 2 outer surfaces. I hope it makes the problem easier to understand.

CU

Nicolas

Mon, 02/21/2011 - 09:23

You will not find in OCCT such functionality. But OCCT can help you to make approximation. You need somehow to compute points representing the middle surface. Then use GeomPlate package or SSP product to make the surface from points.

Some consideration about getting middle points: you can use QHull algorithm to produce the Voronoi diagram in 3D space, which can be used to compute mid points.

Mon, 02/21/2011 - 19:28

Thanks for the helpful hints;-)

Wed, 12/30/2020 - 13:55

Whetehr you are able to done this?