Hello Sir,
I used to connect the '*Out Mesh*' to the inMesh.
Just as you said, I change it to *worldMesh[0]*, and it works !!! But I
don't know why...
Can you tell me the difference between worldMesh and Out Mesh?
Thank you very much
Yixiong Xu
2019.01.05
在 2019年1月4日星期五 UTC+8下午11:55:03，serguei.k...@gmail.com写道：
>
> Hi Yixiong,
> Are you connecting worldMesh[0] as input for inMesh?
>
> On Thu, Jan 3, 2019 at 11:46 PM 徐一雄 <xuyixi...@gmail.com <javascript:>>
> wrote:
>
>> Hello everyone, i'm a newbee to maya python API.
>> Recently, I'm struggle in the single ray tracer.
>> I build a custom MPxNode to compute the hitPoint when the ray hit the
>> sphere.
>> The ray is build by 2 locators in space.
>> If the sphere is at the origin point of the world space, everything seems
>> OK.
>> But here is the* problem*:
>> When I transform the sphere object, e.x translate a little distance. The
>> hitPoint should translate on the sphere but now it doesn't .
>> I know that when I transform the sphere, the input values of the custom
>> node have't change and compute function doesn't be called.
>> I have tried that to add a transform attribute to call the compute
>> function but it doesn't work. I think the hitPoint should be calculate by
>> multiply a matrix.
>> So how can I achieve that when I transform the sphere, the hit point on
>> the sphere also change by the direction of the ray.
>> Thank you very much.
>>
>> Here is the *code*:
>>
>> import maya.OpenMaya as om
>> import maya.OpenMayaMPx as ompx
>>
>> nodeName = 'RayTracer'
>> nodeID = om.MTypeId(0X100fff)
>>
>>
>> class MeshIntersectionNode(ompx.MPxNode):
>> # Class Attrs
>> # INPUT
>> Loc_1_Pos = om.MObject()
>> Loc_2_Pos = om.MObject()
>>
>> inMesh = om.MObject()
>>
>> # OUTPUT
>> Loc_3_Pos = om.MObject()
>>
>> def __init__(self):
>> ompx.MPxNode.__init__(self)
>>
>> def compute(self, plug, dataBlock):
>> if plug != MeshIntersectionNode.Loc_3_Pos:
>> return om.kUnknownParameter
>>
>> locator1Vector =
>> om.MVector(dataBlock.inputValue(MeshIntersectionNode.Loc_1_Pos).asFloatVector())
>> locator2Vector =
>> om.MVector(dataBlock.inputValue(MeshIntersectionNode.Loc_2_Pos).asFloatVector())
>> inputMeshObj =
>> dataBlock.inputValue(MeshIntersectionNode.inMesh).asMesh()
>>
>> direction = om.MFloatVector(locator2Vector - locator1Vector)
>>
>> sourcePoint =
>> om.MFloatPoint(dataBlock.inputValue(MeshIntersectionNode.Loc_1_Pos).asFloatVector())
>>
>> inputMeshMFn = om.MFnMesh(inputMeshObj)
>>
>> hitPoints = om.MFloatPoint()
>>
>> tolerance = float(0.0)
>>
>> inputMeshMFn.closestIntersection(sourcePoint, direction, None, None,
>> False, om.MSpace.kWorld,
>> 10000.0, False, None, hitPoints,
>> None, None, None, None, None, tolerance)
>>
>> outputPoint = dataBlock.outputValue(MeshIntersectionNode.Loc_3_Pos)
>>
>> if hitPoints[0]:
>> outputVector = om.MFloatVector(hitPoints.x, hitPoints.y,
>> hitPoints.z)
>> else:
>> outputVector = om.MFloatVector(0.0, 0.0, 0.0)
>>
>> outputPoint.setMFloatVector(outputVector)
>>
>> dataBlock.setClean(plug)
>>
>>
>> def nodeCreator():
>> return ompx.asMPxPtr(MeshIntersectionNode())
>>
>>
>> def nodeInitializer():
>> MFnNumericAttr = om.MFnNumericAttribute()
>> MFnMeshAttribute = om.MFnTypedAttribute()
>>
>> # create attribute
>> # input
>> MeshIntersectionNode.Loc_1_Pos =
>> MFnNumericAttr.createPoint('Locator1Position', 'Loc1Pos')
>> MFnNumericAttr.setWritable(1)
>> MFnNumericAttr.setKeyable(1)
>> MeshIntersectionNode.addAttribute(MeshIntersectionNode.Loc_1_Pos)
>>
>> MeshIntersectionNode.Loc_2_Pos =
>> MFnNumericAttr.createPoint('Locator2Position', 'Loc2Pos')
>> MFnNumericAttr.setWritable(1)
>> MFnNumericAttr.setKeyable(1)
>> MeshIntersectionNode.addAttribute(MeshIntersectionNode.Loc_2_Pos)
>>
>> MeshIntersectionNode.inMesh = MFnMeshAttribute.create('inMesh', 'im',
>> om.MFnData.kMesh)
>> MFnMeshAttribute.setWritable(1)
>> MFnMeshAttribute.setKeyable(1)
>> MeshIntersectionNode.addAttribute(MeshIntersectionNode.inMesh)
>>
>> # output
>> MeshIntersectionNode.Loc_3_Pos =
>> MFnNumericAttr.createPoint('Locator3Position', 'Loc3Pos')
>> MFnNumericAttr.setWritable(0)
>> MFnNumericAttr.setReadable(1)
>> MeshIntersectionNode.addAttribute(MeshIntersectionNode.Loc_3_Pos)
>>
>> # make influence
>> MeshIntersectionNode.attributeAffects(MeshIntersectionNode.Loc_1_Pos,
>> MeshIntersectionNode.Loc_3_Pos)
>> MeshIntersectionNode.attributeAffects(MeshIntersectionNode.Loc_2_Pos,
>> MeshIntersectionNode.Loc_3_Pos)
>> MeshIntersectionNode.attributeAffects(MeshIntersectionNode.inMesh,
>> MeshIntersectionNode.Loc_3_Pos)
>>
>>
>> def initializePlugin(mObj):
>> mPlugin = ompx.MFnPlugin(mObj, 'Yixiong Xu', '1.0')
>>
>> try:
>> mPlugin.registerNode(nodeName, nodeID, nodeCreator, nodeInitializer)
>> except:
>> raise RuntimeError
>> print 'Failed to register node.'
>>
>>
>> def uninitializePlugin(mObj):
>> mPlugin = ompx.MFnPlugin(mObj)
>>
>> try:
>> mPlugin.deregisterNode(nodeID)
>> except:
>> raise RuntimeError
>> print 'Failed to deregister node.'
>>
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