Calculate angles and distances from XYZ-points

[Giake]

Hello,

From 3D, I export xyz points and polygons in ASCII file to Excel.
I need to cut and mill in wood all polygons but for this I need to know the exact measurements and angles from the points.
When a polygon touch another I need to know the mill angle to put them nice together.

If someone can help me with a few formulas or VBA i will be very happy
I think i found the formulas for distance but not sure...

To help you I made example with a few measurements in the attachment.

Thank you for read this,

Gia

XYZ.xls

[vgr]

excel is not built for stuff like this..... you might want to take a look at autocad inventor

[MrShorty]

I don't know, vgr, I think Excel can do this sort of thing just fine. As you say, there are almost certainly programs (like a CAD program) that already have the geometric/trigonometric formulas for this sort of thing pre-programmed in which would make it easier. But, if we give Excel the proper formulas, Excel is perfectly capable of performing geometric/trigonometric calculations for us.

I guess, Giake, I would ask you this question: What exactly do you need help with? Do you know the geometric/trigonometric formulas for this and just need help putting those formulas into Excel? If so, I would point you to this list of math and trig functions http://office.microsoft.com/en-us/ex...944.aspx?CTT=1 which will help you understand how to use each of Excel's trig functions. If you need further help understanding how to build the formulas in Excel, explain the formulas to us (to save us the work of deriving the functions ourselves) and we'll help you put them into Excel.

If your question is more "how do I use geometry/trigonometry to derive the formulas", then let us know. Some of us here should understand geometry well enough to help you derive the formulas (though someone on a CAD or math/geometry forum might be able to do the derivation faster because they will likely be more familiar with the geometry at the start).

[Giake]

Hello MrShorty,

We work in Cinema 4D but the advantage of Excel is for us the presentation of our work as student-artist. With imagination, VBA and formulas we can reach in Excel our dreams…
The only thing that stop us is the formula or VBA/functions to calculate the angle between 3-points.
And maybe the z-distance is no need?
We got the formula to calculate the distance between three points from the Dutch-forum and made mistake to put our problem in the English-forum too. Apologize for this!

We want to thank you for the link, your time and reply,

Gia & Christina

[vgr]

wow. Good stuff! never knew excel could be used for something like this!

[oeldere]

and here is the link to the dutch free forum.

http://www.worksheet.nl/forumexcel/s...ad.php?t=85854

The give formula is:

dutch =WORTEL((C7-C6)^2+(D7-D6)^2+(E6-E7)^2)

English

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[Giake]

@oeldere,
You can find work formula in my attachment above…

Have study the link from MrShorty and I think the angle is solvable with cosines
Its look alike that first I need to know distance of the 3-points before calculate the angle!?
Let say I have A, B and C points en A is the center point
First I calculate the distance between A-B, B-C and C-A by using SQRT and the 3 YXZ-points.
The angle of A(center point) = ARCCOS((B^2-A^2-C^2) / 2*A*C )

Not sure if this is correct and for the angle I don’t need any more the z-point, right?

[oeldere]

@Giake

I don't see any attachment added.

P.s. I can't help you with this question.

[Giake]

@oeldere,
Oh, look above in the first post just under my name(Gia) you will find (normally) "XYZ.xls"
You can later always ask for full working example!
Sorry for this

[MrShorty]

First I calculate the distance between A-B, B-C and C-A by using SQRT and the 3 YXZ-points. The angle of A(center point) = ARCCOS((B^2-A^2-C^2) / 2*A*C ) Not sure if this is correct and for the angle I don’t need any more the z-point, right?

I'm not sure if it is right either, because I can't quite picture the triangle you are using for this derivation.

If B is the right angle in the triangle, and A is the center point, that makes C the point of interest (P1, for example). The line A-C is the hypotenuse of the right triangle, and line A-B and B-C are the legs of the triangle. line AB is the leg adjacent to A, and B-C is the leg opposite A. From the definition of sine, sin(A)=BC/AC (opposite over hypotenuse). The other basic trig functions are defined similarly (http://en.wikipedia.org/wiki/Trigonometric_functions ). Given the length/distances BC and AC, the angle A can be found from ASIN(BC/AC). Note that in Excel (like most programming languages) angles are in terms of radians rather than degrees.

[Giake]

Thank you very much MrShorty for the info, we will now study all your info!

[Giake]

Dear forum users, if you like this thread, here you can find complete file from by Alphamax