Reading Houdini Particle Attributes into C4D via Alembic as Particle Groups
Posted: Wed Sep 09, 2026 8:19 am
Hey folks, I have a question about how Octane reads Houdini particle attributes in Cinema 4D via Alembic - specifically when the particles are imported as native C4D particle groups rather than as geometry points.
I've tried a couple of approaches so far:
1. I first simulated some particles directly in Cinema 4D with varying radii and rotations. I exported them as Alembic, imported the Alembic back into C4D, and rendered them with Octane. Everything worked perfectly - Octane correctly picked up both the particle radius and rotation.
2. Based on that, I imported the C4D-generated particle Alembic into Houdini, unpacked it, and inspected the attributes it contained, such as `c4dAlignment`, `width`, etc.
I then created another particle simulation in Houdini and renamed/mapped the Houdini attributes to their apparent C4D equivalents - for example, `pscale` → `width`, `orient` → `alignment/c4dAlignment`, and so on.
However, when I exported this Houdini simulation as Alembic and imported it into Cinema 4D, Octane was unable to pick up any of those attributes, and the particles did not render at all.
As a comparison, I tested the exact same Houdini-generated Alembic with Redshift in C4D, and Redshift correctly reads the attributes and renders the particles with the expected radius and rotation.
Does anyone know what I might be missing here?
I'm working with a fairly large number of particles, so importing them as actual geometry becomes very heavy and significantly slows down playback. Importing them as native particle groups, on the other hand, performs much more smoothly, so I'd really like to keep that workflow if possible.
Any clues or insight into what Octane expects from the Alembic particle schema or attributes would be greatly appreciated. Thanks!
I've tried a couple of approaches so far:
1. I first simulated some particles directly in Cinema 4D with varying radii and rotations. I exported them as Alembic, imported the Alembic back into C4D, and rendered them with Octane. Everything worked perfectly - Octane correctly picked up both the particle radius and rotation.
2. Based on that, I imported the C4D-generated particle Alembic into Houdini, unpacked it, and inspected the attributes it contained, such as `c4dAlignment`, `width`, etc.
I then created another particle simulation in Houdini and renamed/mapped the Houdini attributes to their apparent C4D equivalents - for example, `pscale` → `width`, `orient` → `alignment/c4dAlignment`, and so on.
However, when I exported this Houdini simulation as Alembic and imported it into Cinema 4D, Octane was unable to pick up any of those attributes, and the particles did not render at all.
As a comparison, I tested the exact same Houdini-generated Alembic with Redshift in C4D, and Redshift correctly reads the attributes and renders the particles with the expected radius and rotation.
Does anyone know what I might be missing here?
I'm working with a fairly large number of particles, so importing them as actual geometry becomes very heavy and significantly slows down playback. Importing them as native particle groups, on the other hand, performs much more smoothly, so I'd really like to keep that workflow if possible.
Any clues or insight into what Octane expects from the Alembic particle schema or attributes would be greatly appreciated. Thanks!