Re: minimum distance from a point to a surface

Rune Allnor <allnor@xxxxxxxxxxxx> wrote in message <a36b50ab-a0fa-48a2-b9b9-7ca09858c8c3@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>...
On 29 Jan, 00:33, "Robert Kirdeikis" <kirde...@xxxxxxxxxxx> wrote:
Hey, I need to compute the minimum distance between a point and a surface=
. I have created the 3d surface using convhulln so i know the vertices of e=
very point and i am able to get the minimum distance to a single point on m=
y surface using the dsearchn function. But what i would like to get is the =
minimum distance to the surface created, not the minimum distance to the po=
ints used to create the surface. I hope my wording of my problem hasn't con=
fused you guys to much and thank you in advance

I assume you are building the surface as a tesselation based
on the points you have. If so, the closest point on the surface
ought to be located close to the closest vertex. I would have
checked the equations for the planes for all the faces that
intersect in the closest verex: Project the point onto each
such plane, and use any projection that falls inside the
face as a candidate for the closest pont. That will leave you
with a finite set of candidates for the closest point (although
not necessarily a unique solution).


yes i am building a tessellation sphere based on a data file full of x,y,z data points. Im not sure how to get the equations of the planes in my tessellated sphere. To add to the difficulty, i alter the shape of my sphere through my program so the points are no longer equally spaced. I have looked at 3d interpolation to try and find the equations of the surfaces of the facets but was confused how to use it to get the surfaces. If anybody has anything that could help me out, please let me know

.

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