[Maya-Python] aligns obj to a face normal using api

[Fleming Lin]

hi guys...I have done many research online and still can't figure out where
I did wrong....all I want...is just create one angry puffer fish( or
"sphere")...please help...

...so my first idea was to collect all the facial normal using MItMeshPolygon.getPolygonNormal((
faceIter.index(), om.MSpace.kWorld)) and then set both the position and
rotation base on the normal I got...but here is what I get....(see code and
result attach below). And I noticed that after I moved the sphere, the
"thorns" would remained at the origin instead of translated with the
sphere..... So I then use the om.MItMeshPolygon.center(om.MSpace.kWorld) to
get the center position of the face for the translation and normal for the
rotation... Now I get the position right..but still the wrong
rotation....what should I do now? : <

[image: Screen Shot 2018-11-06 at 9.57.11 PM.png]

[image: Screen Shot 2018-11-06 at 9.58.57 PM.png]

[image: Screen Shot 2018-11-06 at 9.59.14 PM.png]


changed I made

[image: Screen Shot 2018-11-06 at 10.15.52 PM.png]

[image: Screen Shot 2018-11-06 at 10.14.59 PM.png]





any help would be ultra appreciated!!!

[Neil Roche]

Hi,

The method getPolygonNormal will return a vector not a rotation, so you
will need to either do some vector math to get the euler rotation from the
vector using the position at the centre of the face and the normal vector
to start with or maybe use an aimConstraint to align your cone along the
vector.

This should help:

http://www.chrisevans3d.com/pub_blog/maya-python-vector-math-primer/

Post by Fleming Lin
hi guys...I have done many research online and still can't figure out
where I did wrong....all I want...is just create one angry puffer fish( or
"sphere")...please help...
...so my first idea was to collect all the facial normal using MItMeshPolygon.getPolygonNormal((
faceIter.index(), om.MSpace.kWorld)) and then set both the position and
rotation base on the normal I got...but here is what I get....(see code and
result attach below). And I noticed that after I moved the sphere, the
"thorns" would remained at the origin instead of translated with the
sphere..... So I then use the om.MItMeshPolygon.center(om.MSpace.kWorld) to
get the center position of the face for the translation and normal for the
rotation... Now I get the position right..but still the wrong
rotation....what should I do now? : <
[image: Screen Shot 2018-11-06 at 9.57.11 PM.png]
[image: Screen Shot 2018-11-06 at 9.58.57 PM.png]
[image: Screen Shot 2018-11-06 at 9.59.14 PM.png]
changed I made
[image: Screen Shot 2018-11-06 at 10.15.52 PM.png]
[image: Screen Shot 2018-11-06 at 10.14.59 PM.png]
any help would be ultra appreciated!!!

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