# Round filllet coordinate

1. Oct 17, 2007

### yoman

1. The problem statement, all variables and given/known data

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" collinear.

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?

2. Relevant equations

3. The attempt at a solution

2. Oct 19, 2007

### Gokul43201

Staff Emeritus
Is this a math project or a machining project?

Can you write down the equations of the 2 lines? From the equations, can you find the angle between them? Does noticing that the center of the circle lies on the angle bisector help (there's a right triangle of known angles that can be drawn)?