Taylor Petrick

TOPs doesn't unlock HDAs in the general case.

Does your HDA contain ROP Fetch nodes that cook in process and also point to a ROP in the HDA itself, for example a ROP Geometry? The ROP Fetch will unlock the HDA that contains the ROP being cooked, because it often needs to set parameters on that ROP. You can disable that behavior using the "Unlock Target ROP Node" as described in the documentation: https://www.sidefx.com/docs/houdini/nodes/top/ropfetch.html#unlocktargetrop [www.sidefx.com]

Pressing the cook button on the TOP triggers a non-blocking cook, which mean the cook runs in the background. This is typically not suitable in a headless session because nothing will wait on the cook to finish, and it'll be canceled when it reaches the end of your script and Hython exits.

If you're triggering a cook programmatically in a script you should use one of the various hou.TopNode methods to do so, and pass in the block=True argument. That way your script actually waits for the cook to complete. For example: https://www.sidefx.com/docs/houdini/hom/hou/TopNode.html#cookOutputWorkItems [www.sidefx.com]

pdg.Graph has all of the same methods as pdg.WorkItem for adding/setting attributes. For example, in a Python Script. you can use the following to create a global string attribute named "example" that appears in the MMB menu on the TOP Network itself: