I've written a custom Packed Primitive for Houdini-16.5 and would like to use Houdini Engine to Cook an HDA that outputs these PackedPims, however they come out as Invalid Parts.

Is there something specific that I have to implement in my PackedPrim to have it be handled by HoudiniEngine? Also if it was handled what would I receive in the Part?

Cheers,
Tim

Hi,

It's hard to tell without knowing what are your custom packed prims and what do they contain? Can you give us more details?

Sure.

The Packed Prim represents a location within an external scene description (similar to the Usd Packed Prim).

I have implemented;

1. an unpack function that returns Packed Prims for sub items in the scene description and eventually unpacks to detail when it reaches the leaves.
2. a GT_Primitive to support display, with the full geo result returned as a GT_PrimInstance.
3. getPackedDetail to return a GU_Detail that matches the GT_Primitive.

Working with the Packed Prim inside Houdini is fine, I just don't get any valid parts back from Engine.

It's hard to tell without knowing the actual implementation, but the issue is likely to be caused by HAPI either not being able to refine your custom primitive when converting the geometry, or simply not recognizing it as something it can process.

Does your custom prim has refine/refinetoInstances/flattenInstances ?