Hello !

I'm currently using houdini engine in production and I wanted to know how to output multiples mesh in Maya.

For the moment I have tried to put multiples Output SOP and set Maximum Outputs to 3 (operator type properties > Basic tab) which worked in Houdini but not in Maya… I just have the first output as a mesh.

Maybe I do not use the engine correctly… Is it possible to have some help ? Also is there a documentation or something for the Engine in Maya ?

Thanks a lot !

ValentinD

If you have a pre-determined number of output, you could create an Object network asset. Each Object node will be outputted into its own mesh node in Maya.

But if you have a case like fracturing where the number of pieces can change easily (due to parameter value or simulation), then it's more difficult at the moment. For that case, there are generally two workarounds.

You could use Houdini groups to identify the pieces. The Houdini groups would then be converted into Maya sets. You can then operate on the pieces using the Maya sets.

If the pieces are connected to each other, you could use “Edit Mesh -> Separate” to separate out the pieces from the Maya side.

Thank you so much, It helps a lot !!

Is there a new method available? Specifically I have the worst case scenario where I don't know the number of Pieces to output.
In Houdini Engine for Unreal we can just pack geo and each packed primitive gets output as a separate object (it's been a while, so this might have changed, since I last tried). Could we have that in Maya, as well?

Not yet - this is not as easy to do in Maya. If you want an separate object, it needs to have a shape and transform node.

What do you need to do the the output pieces after the geo comes out of Houdini, where it would be preferable to have them as separate shapes? Are the number of output pieces changing during playback, or during interactive editing?

AutoSync Outputs will rebuild the outputs if the number of outputs changes when you are just modifying the inputs interactively. But Maya really does not like the dependency graph changing spontaneously during playback. e.g. if I turn on Split Geos By Group and Auto Sync Outputs on my fracture sim, it won't update the outputs until the playback is stopped (in DG mode, that is - in Serial/Parallel mode it may well crash) And auto syncing will obliterate any downstream edits that you applied to the outputs previously

If you leave the output geo pieces in one object and then use Maya's polySeparate at a frame where you have the maximal number of pieces,and you'd have enough output shapes to represent that one particular sim. Although you'd have to delete and reseparate the outputs if the sim changed and the number of outputs increased.

I am currently looking at it from a tool generation perspective. For example you put in a static mesh and get fractured pieces out. In this scenario, there would be no animation, but it would be important that each piece would have its own pivot and transform (defined in Houdini) as well as other data that is different from piece to piece.

In general the most desirable solution would give similar results across Unreal/Maya/Unity etc. So when I pack my pieces and I put it in Unreal I bake to separate Static Mesh Objects and if I put the same HDA in Maya I expect to get separate Mesh Objects. In an ideal world I would have to make very few switches to have a compareable experience across platforms. I would only have to add/remove things that are 100% platform specific. This would allow me to easily use and reuse tools across different platforms.

is this solved?
is there an Auto Group Connected Pieces ?

I am also curious if you were able to get separate meshes to output from Houdini to Maya. Can you share the method if you were able to?