how to get the closest point to a gpucache.
- Im3dJoe - Polygon Lab
I use MFnMesh.closestIntersection a lot to get the closest point on a mesh,
but I found it very slow to a dense mesh,
I have been told that Quaddraw use MPxSurfaceShape::closestPoint to snap point on the gpucache, but I can not find any example of how to use it,
cheers
Joe
Marcus Ottosson
It does the opposite.
Any MFn* class is called a “function set”, and contains functions you can use for a particular type of Maya object. Like mesh-related functions in MFnMesh. But MPx* classes are things that you the developer implement to provide Maya with data. In this case, the closestPoint function is what you implement to give Maya some idea of where the closest point is on your custom node. Your custom node could, for example, be a mesh that you generate and draw yourself. Something Maya normally does not know about or know how to query. The closestPoint method is a way for you to give Maya that missing information; presumably it would use that when snapping a Maya manipulator or pivot to a point on that custom node.
As for a quicker alternative, there are other mesh-related tools for finding points, such as MFnMesh::getClosestPoint, that has different performance/feature tradeoffs.
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- Im3dJoe - Polygon Lab
Thanks for the explanation,
after some Google time,
I will still require to use MFnMesh.closestIntersection,
as I need to trace from the mouse position.
do you know Is there a way to make it work for gpuCache data?
At moment it only works with polygon mesh.
is there a way to read gpuCache without importing it as a polygon mesh.
gpuCache is just way more interactive in the viewport compared to mesh.
once again thanks for sharing your knowledge.
Marcus Ottosson
I don’t know much about the gpuCache node specifically, but to me it looks like exactly the kind of custom node that would require that closestPoint implementation in order for Maya to provide point snapping similar to a traditional polygon mesh; like when you hold the V key and drag the translate manipulator on the mesh. I would expect Maya to either provide a dedicated function set for operating on this particular node type, or that there simply is no way of doing it. Similar to if you were to write your own custom node and not have or provide a function set to operate on it.
Maybe there is something in the cmds module, or perhaps the native closestPointOnMesh node calls on its implementation for you? If you were to implement your own surface node, you could implement that method and put a print statement there. Then, you can see when and where Maya calls this function.
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Joe
On 7 Apr 2023, at 5:57 pm, Marcus Ottosson <konstr...@gmail.com> wrote:
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