[Maya-Python] Find the closest point on mesh

[illunara]

Hi everybody
Maya already had closestPointOnMesh node to do it, but i don't know how it
working from inside. Any chance to read the source of this node?

Anyway, i try to write one using openMaya, but its not working either, here
is the code. Please tell me where it goes wrong. Thanks

https://gist.github.com/illunara/4a456d1407f9f60a1089

[Eduardo Grana]

Hello Illunara,

Haven't done this for a while, but i remember using
from MFnMesh the getClosestPoint function instead,
not sure if this is what you are after...

MStatus
<http://docs.autodesk.com/MAYAUL/2013/ENU/Maya-API-Documentation/cpp_ref/class_m_status.html>
getClosestPoint(const MPoint
<http://docs.autodesk.com/MAYAUL/2013/ENU/Maya-API-Documentation/cpp_ref/class_m_point.html>
& toThisPoint,MPoint
<http://docs.autodesk.com/MAYAUL/2013/ENU/Maya-API-Documentation/cpp_ref/class_m_point.html>
& theClosestPoint,MSpace::Space
<http://docs.autodesk.com/MAYAUL/2013/ENU/Maya-API-Documentation/cpp_ref/class_m_space.html#ab11a1dda34491acff014ddfc9e6bafb8>
space = MSpace::kObject,int * closestPolygon = NULL )const

I cant find the code where i used it,
I'll keep looking...
Cheers,
Eduardo

Post by illunara
Hi everybody
Maya already had closestPointOnMesh node to do it, but i don't know how it
working from inside. Any chance to read the source of this node?
Anyway, i try to write one using openMaya, but its not working either,
here is the code. Please tell me where it goes wrong. Thanks
https://gist.github.com/illunara/4a456d1407f9f60a1089
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[Tuan Nguyen]

Hi Graña
I tried, and fail too. The result is on mesh's surface, but clearly not the
closest point :(

[Eduardo Grana]

Hello,
I've made this simple test,

http://pastebin.com/6xtHkt7t

Hope its usefull, otherwise let me know.
Be aware that is with python api 2.0, and you cant mix it with regular
python api. I used it to avoid the pointers that are a little bit messy...
Cheers,
Eduardo

Post by Tuan Nguyen
Hi Graña
I tried, and fail too. The result is on mesh's surface, but clearly not
the closest point :(
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[Tuan Nguyen]

First of all, it works, thanks a lots, and for telling me about python api
2 too :D

Just a little confuse about MSpace, i used MSpace::kObject, but lately,it
got multiply with mesh's matrix, so they should be identical, right?

[Chad Vernon]

If you are calculating many closest points, you should use MMeshIntersector
as it will be a lot faster.

Post by Tuan Nguyen
First of all, it works, thanks a lots, and for telling me about python api
2 too :D
Just a little confuse about MSpace, i used MSpace::kObject, but lately,it
got multiply with mesh's matrix, so they should be identical, right?

[Tuan Nguyen]

Hi Chad
I attach the code using MMeshIntersector in the first post, but the result
gone wrong :(
can you take a quick look at it please?

[Chad Vernon]

You're passing in the wrong matrix. You don't want the inverse you just
want the inclusive matrix :


mat = meshPath.inclusiveMatrix()
resultPoint = om.MPoint()
polyIntersect = om.MMeshIntersector()
polyIntersect.create(shape, mat)
ptON = om.MPointOnMesh()
polyIntersect.getClosestPoint(pt, ptON);
resultPoint = om.MPoint(ptON.getPoint().x, ptON.getPoint().y, ptON.getPoint().z)

Post by Tuan Nguyen
Hi Chad
I attach the code using MMeshIntersector in the first post, but the result
gone wrong :(
can you take a quick look at it please?

[Tuan Nguyen]

Thank Chad, it works beautifully :D

Post by Chad Vernon
You're passing in the wrong matrix. You don't want the inverse you just
mat = meshPath.inclusiveMatrix()
resultPoint = om.MPoint()
polyIntersect = om.MMeshIntersector()
polyIntersect.create(shape, mat)
ptON = om.MPointOnMesh()
polyIntersect.getClosestPoint(pt, ptON);
resultPoint = om.MPoint(ptON.getPoint().x, ptON.getPoint().y, ptON.getPoint().z)

Post by Tuan Nguyen
Hi Chad
I attach the code using MMeshIntersector in the first post, but the
result gone wrong :(
can you take a quick look at it please?
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[igo rov]

Hi , I know its a old post...but how to you get the world position of the
point which is MFloatPoint, 3d Point in objects space?

Post by Tuan Nguyen
Thank Chad, it works beautifully :D

Post by Chad Vernon
You're passing in the wrong matrix. You don't want the inverse you just
mat = meshPath.inclusiveMatrix()
resultPoint = om.MPoint()
polyIntersect = om.MMeshIntersector()
polyIntersect.create(shape, mat)
ptON = om.MPointOnMesh()
polyIntersect.getClosestPoint(pt, ptON);
resultPoint = om.MPoint(ptON.getPoint().x, ptON.getPoint().y, ptON.getPoint().z)

Post by Tuan Nguyen
Hi Chad
I attach the code using MMeshIntersector in the first post, but the
result gone wrong :(
can you take a quick look at it please?
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[Eduardo Grana]

Yes, it should be the same, although I don't know how MMeshIntersector
handles spaces.

Post by Tuan Nguyen
First of all, it works, thanks a lots, and for telling me about python api
2 too :D
Just a little confuse about MSpace, i used MSpace::kObject, but lately,it
got multiply with mesh's matrix, so they should be identical, right?
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