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Topic: Calculating the area of a closed 3-D path or ring
Replies: 23   Last Post: Mar 25, 2013 4:54 PM

 Messages: [ Previous | Next ]
 Math Guy Posts: 20 Registered: 5/21/05
Re: Calculating the area of a closed 3-D path or ring
Posted: Mar 15, 2013 12:33 AM

Ray Koopman wrote:

> > Once the plane is known, the points are translated to the
> > coordinate system of the plane, their Z coordinates are ignored
> > or dropped, and this becomes a 2-dimensional area calculation.

>
> That's exactly what I suggested :)

Hmm - I guess I didn't read that far...

> You haven't said whether the ordering of the points around the
> loop is given or not.

The user will specify the markers to be used (there are other markers on
the heart which will not be involved in this ring). A routine will
identify the order by picking one point and then determine which of the
remaining points is closest, and will piece-wise work it's way around
the ring. This should avoid any errors if the user gives the order
incorrectly.

> Also, what do you want to do if the loop is not convex?

Do you mean what if the loop looks like a potato chip with a bite taken
out of it?

I don't see how that would affect the proposed area calculation method.

Date Subject Author
3/12/13 Math Guy
3/13/13 Ray Koopman
3/13/13 Nicolas Neuss
3/13/13 Peter Spellucci
3/13/13 Shmuel (Seymour J.) Metz
3/13/13 Frederick Williams
3/13/13 Brian Q. Hutchings
3/14/13 fom
3/14/13 fom
3/14/13 Math Guy
3/15/13 Ray Koopman
3/15/13 Math Guy
3/15/13 fom
3/16/13 Ray Koopman
3/16/13 fom
3/16/13 Math Guy
3/16/13 fom
3/16/13 Ray Koopman
3/15/13 Peter Spellucci
3/16/13 Math Guy
3/17/13 Ray Koopman
3/17/13 Math Guy
3/18/13 Ray Koopman
3/25/13 Gib Bogle