
Re: Calculating the area of a closed 3D path or ring
Posted:
Mar 15, 2013 12:36 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 2dimensional 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 piecewise 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.

