Round filllet coordinate for pipeline 1

[Yoman228]

I have 3 known point, with coordinate P1-(X1, Y1, Z1), P2-(X2, Y2, Z2), P3-(X3, Y3, Z3).

straight line is draw from P1 to P2, P2 to P3. they are "not" colinear.

I would like to fit a round fillet to the conner with a "Known" radius of R, and I would like to know the coordinate of the 2 tangent point and the center of the fillet circle.

How can I calculated it in 3D coordinate with a sample single equation for each of the tangent point and center of the fillet, so I can use in Excel. Is this possible?

 

[BigInch]

Work in the plane that contains the 3 points. Set the radius and centerline of the arc, find the tangent points, then translate all points you need back to global X,Y,Z coordinates.

http://virtualpipeline.spaces.msn.com

 

[narenr]

I presume you have more than 1 set of coordiante and hence you want put it in Excel spreadsheet. My first impression is not possible in Excel as it requires more than just cell formulas, you will need to program the filleting in VB.

You do much easier in AutoCAD but you will be repeative or you could even simplify using a script file after you do the first set.



Narendranath R
Pipeline engineering is made easy with state of the art computer software, visit

http://www.narendranath.itgo.com.

 

[Yoman228]

The main reason that I use excel is that the user can input the Workpoint as detailed in the drawing. and the excel can calculate the TP and center of the circle and this would be the coordinate of a FEA input.
I understand that can be done in any cad package, but If I can find a way to do this in Excel. It will be greate as I do not need to go through the draft man each time i do small chane to my model.

I know some programing of VBA. but since I not touch the vector for 10 years now. can anyone help me the maths behind it pls.

 

[Yoman228]

BigInch, I have ben able to find the solution the center of circle and tangent by setting P1 as (X, 0, 0), P2 as (0,0,0)
and P3 as (X, Y, 0)
But how can I map back the coordinate please?

 

[BigInch]

To get from global coordinates to your working plane you put the global Axes X, Y and Z origin at point 1 (I hope) and then had to rotate point 2 and 3 about each global X, Y, Z axis by angles a,b,c using R * cos and sin functions. You didn't do it exactly like that, did you?

Have a look at section 1 and 2 of this and see if it helps,

http://en.wikipedia.org/wiki/Transformation_(mathematics)

http://virtualpipeline.spaces.msn.com

 

[Yoman228]

To reword my question, how can I use the translate the formular below into the my global 3D coordinate system?

http://www32.ocn.ne.jp/~yoda/AutoCADVBAEnglish/Fillet_keisansiki.htm

Many thanks

 

[BigInch]

Sorry. I have no idea about how to use A/CD.

http://virtualpipeline.spaces.msn.com