Hey Everyone,
Finally diving back into the world of the python api and i'm pulling
my hair out trying to get the intersection point on a nurbs surface.
I'm trying this on a scene with a nurbs plane at 0 0 3 and a
raystartingpoint of 0, 0, 0.
In this code, raystartingpoint is 0 0 0 1, and alongthisdirection is
hardwired to 0 0 1 down z. Maya will crash If I have the
calculateExactHit set to True. Otherwise, it's not giving results I
trust.
My first question is what the heck is kMfnNurbsEpsilon and how to I
address it from python. The only reference I've found is in this call
and the nurbs curve and both are args. All c++ examples I've found
call it directly by name. I've set this to 1, but this is a total
guess and could be the cause of my issues.
BONUS QUESTION: Additionally, assuming I can get this to work. I'm
expecting the 3rd vertical column of the .xformMatrix of a locator
would be the 'alongthisdirection' arg expected from MFnNurbsSurface,
is this a correct assumption. If not how does one get the direction of
a object.
Can someone shed some light on what's up here? Thanks a ton!!!!
Doug
Here's my test code:
def getIntersection():
slist = om.MSelectionList()
om.MGlobal.getSelectionListByName('nurbsPlaneShape1', slist)
nurbsObj = om.MObject()
nurbsDag = om.MDagPath()
slist.getDependNode(0, nurbsObj)
slist.getDagPath(0, nurbsDag, nurbsObj)
fnSurface = om.MFnNurbsSurface(nurbsDag)
spc = om.MSpace.kWorld
#locatorXformMatrix = mc.getAttr("locator2" + ".xformMatrix")
#direction = om.MVector(locatorXformMatrix[2], locatorXformMatrix
[6], locatorXformMatrix[10])
startPoint = om.MPoint(0.0, 0.0, 0.0, 1)
direction = om.MVector(0, 0, 1)
uSU = om.MScriptUtil()
vSU = om.MScriptUtil()
uPtr = uSU.asDoublePtr()
vPtr = uSU.asDoublePtr()
interPoint = om.MPoint()
toleranceSU = om.MScriptUtil()
tolerance = toleranceSU.asDoublePtr()
om.MScriptUtil.setDouble(tolerance, .1)
value = fnSurface.intersect(startPoint, direction, uPtr, vPtr,
interPoint, toleranceSU.asDouble(), spc, False, None, False, None)
print value
print interPoint.x, interPoint.y, interPoint.z
return (interPoint.x, interPoint.y, interPoint.z)
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