Are Houdini vertex normals supported in Houdini Engine for Maya? My Houdini Engine geometry output should have some hard edges and some soft edges (in Maya terms), but it gets only all soft edges with locked normals (in Maya terms). Also, locked normals are really quite bad in Maya. Is that intended behavior?

I am currently on build 15.5.553 and upgrading would be no problem.

Sorry for the late reply. Outputting vertex normals is supported. However, in Houdini, once the “N” attribute exists, all the normals are read from the attribute. So when geometries are outputted into Maya, if the “N” attribute exists, then all the normals become locked. If the “N” attribute doesn't exist, then all the normals become unlocked.

See the attached HDA for an example of outputting normals.

Also, Houdini doesn't have the concept of soft/hard edges. In Houdini, you can set the normals so that they _look_ soft or _look_ hard. However, since normals are outputted into Maya, the normals are now locked. And when the points are moved around, the normals are not updated.

Thank you awong. I know that Houdini deals with normals in a different way, so I was wondering if it would be possible to add an attribute that Maya could use/interpret to make edges hard or soft in its own way.
It's important, because when you use Houdini to make tools for Maya, you want the tools to create normal information. But if the normals are locked, unlocking them looses all information and while they are locked, a user cannot edit he normals easily.

In Houdini cusped edges are pretty much equivalent to hard edges in Maya. Of course, Houdini offers far more and better tools to edit normals, but for basic geometry operations the cusping information would translate well to Maya. But really, it would be enough to be able to give an attribute to points that says whether this point belongs to a hard edge.
(Note: 3DS Max uses smoothing groups based on faces, but in practice the Maya way of communicating soft and hard edges is much more user-friendly.)

Yup, I thought about doing pretty much that before. Storing the edge information on the vertex is probably the best way right now. But unfortunately, I haven't had the chance to get to that yet.

Would certainly be a great improvement for Maya Houdini Engine. Should I send in an RFE?

Sure, that'd be great!

It's in as: RFE #77444

I found an ok workaround for relatively static geo:
1. Convert your hard edge selection to a point point group selection (in Houdini).
2. In Maya: Select the geo and unlock normals
3. In Maya you should get a selection set with your group name.
Rightclick the selection set and click: Select Set Members
4. In the Maya main menu go to Select->Convert Selection->To Contained Edges

One limitation are cases where the conversion from points to contained edges leads to the selection of edges that were not originally hardened.
A possible work-around would be an algorithm that generates smoothing groups based on faces (like in 3DS Max) and a script in Maya that goes through the selection sets.

A better solution would be if edge-groups were supported in Houdini Engine for Maya by sideFX. Hence I'm gonna make an RFE for that and link that to my other RFE.

- I hope this is helpfull to somebody!