Hey folks

I'd like to import an alembic cache baked in Maya into Houdini. I'd like to use a geometry (from the alembic) instanced on the point cloud (from the alembic). Houdini tells me that there are no particles when I try to use the Instance on Particles tool.

Is there any guideline how to do this?


Cheers


Szabolcs

Hard to say without looking at the alembic.. can you post a cutdown/repro scene with an alembic file to play with?

At a guess, you might be loading the geo in packed mode, meaning houdini may not be able to work with it until you unpack. I've not used the ‘instance on particles’ tool you mention, but it should be simple enough to do by separating out the geo you want to instance to one stream, the points to another, and feed both to a copy sop.

I have a few examples of that (with extra controls for rotation, material assignment, selection etc) here, especially the ‘instance with instance sop’ bit.

http://www.tokeru.com/cgwiki/index.php?title=Houdini#Instance [tokeru.com]

-matt

Meanwhile I figured it out

However how can I extract alembic per point attributes to drive the rotation and scale of the instanced objects?

What's the problem exactly? If you're not seeing extra point attributes, you'll need to post an example abc. If you can see attribs, it should be a matter of creating attribs Houdini expects to control rotation and scale.

Eg, if you have rotationPP and scalePP on your points, you could do something like this in a point wrangle before the copy sop:

@N = v@rotatePP;
@scale = v@scalePP;