NX11 Journal - Orient WCS to Plane of 3 Points 1

[jmarkus]

I'm trying to set my coordinate system (WCS) XY plane to match the plane defined by 3 points: point_coord(3),point_coord(3),point_coord(3).

My code is:

Dim matrix1 As NXOpen.Matrix3x3 = Nothing
matrix1.Xx = point_coord(0).coordinates.X
matrix1.Xy = point_coord(0).coordinates.Y
matrix1.Xz = point_coord(0).coordinates.Z
matrix1.Yx = point_coord(1).coordinates.X
matrix1.Yy = point_coord(1).coordinates.Y
matrix1.Yz = point_coord(1).coordinates.Z
'How do I get the Z point?
matrix1.Zx = point_coord(2).coordinates.X
matrix1.Zy = point_coord(2).coordinates.Y
matrix1.Zz = point_coord(2).coordinates.Z
workPart.WCS.SetOriginAndMatrix(point_coord(4).coordinates, matrix1)

But as you can see, I'm confused...The Z in the matrix would be the point defining the normal to the plane, but I don't know how to get that...

How can I get this WCS oriented using 3 points?

Thanks,
Jeff

 

[ufsure]

You can initialize a matrix with two vectors.

Use UF.UFMtx3.Initialize( double[] x_vec, double[] y_vec, [Out] double[] mtx )

Suresh

http://www.technisites.com.au

 

[jmarkus]

So that made sense to me...until I realized I don't know how to define a vector by 2 points...seems like it would be straightforward but I looked through my NX11 NXOpen .Net API References and User Function Reference and I couldn't figure it out...

I thought it would be the difference between two points like:

dim Xvec as Vector3 = XPt - OriginPt

But apparently I can't perform subtraction on points...

J

 

[ufsure]

Subtract the co-ordinates of points. See below image.

Suresh

http://www.technisites.com.au

 

[jmarkus]

Thanks Suresh. I thought there was a more elegant way than explicitly working with the coordinates, but that makes sense.

Jeff

 

[ufsure]

Using points you could create a direction and obtain its vector. But subtracting point co-ordinates is easier for your purpose.

Direction CreateDirection(Point startPoint, Point endPoint, SmartObject.UpdateOption updateOption)
Vector3d Direction.Vector

Suresh

http://www.technisites.com.au

 

[BubbaK]

The SNAP library has arithmetic for points and vectors. So, in particular, you can get a vector by subtracting one point from another. Snap requires an extra license, but there's a free subset called MiniSnap that includes all the Snap point and vector functions.