Read Houdini Particle Attributes into C4D via Alembic Tweet

[ajiblock]

Hi,
hopefully the title explains it all. I have a particle sim in Houdini, i've cached it and brought it into Octane, It's Alembic, with a few million particles, being read into Octane Scatter and is rendering great. Only problem – the look is heavily baed on the Cd (color diffuse) attribute that I was using in Houdini.

at 21 mins in this video https://vimeo.com/182543771 Rohan Dalvi shows a workaround in Houdini/Octane to color particles by generated color attributes. I know you can typically pick up particle attributes in Alembic, so was wondering if there was a way to emulate what Rohan is doing in C4D Octane, feels like I'm so close to do everything I need except the particle coloring.... Thanks so much !

[Chrmez]

If I get you right, then this is exactly what I am having troubles with too. I've been looking for a solution forever.
The shader in Octane Scatter does absolutely nothing on imported particles. The colors, sizes stay random.

https://cdn.discordapp.com/attachments/ ... .28.35.png

Will be following this thread to hopefully put an end to this issue.

[Chrmez]

After weeks and weeks of researching this I think there's just no way to control Cd(Vector) or any other attributes in Octane C4D. What he is doing in the video you posted is not on material level and seems very limited (only two attributes) but I doubt either of them will work in C4D.

In "that other GPU renderer" you can simply import your alembic to C4D as particles. C4D will then read out the attributes in Thinking Particles and then you just use the attributes in your materials to control everything you need (even pscale). I prefer Octane way more though so Aoktar, if there is any way to get this to work now or in future releases please let us know.

[mlmcgoogan]

Just in case you haven't resolved this yet. It is now possible to get Houdini's Cd attribute into C4D/Octane. Just make sure that the export from Houdini has a Cd attribute at the point level and when you import into C4D, import the particles as geometry (NOT particles). You'll know you're good if you see an Alembic vertex map tag called "Cd" on the object.

You can then use a scatter node with the Alembic object as the surface. Create a sphere (or whatever geo you want), drop it under the scatter node so it becomes the scattered object, and throw an Octane Mat on it. In the mat use an Instance Color node, switch to particle mode, and drag the "Cd" vertex map into the field. Boom, color. Supports full animation of the attribute.

Note that only the Cd attribute seems to be supported currently, this looks to be a C4D/Alembic limitation. Depending on what you're trying to do you can get around this in certain cases by using an attrib rename in Houdini to use a Cd vector to hold whatever arbitrary data you care about.

[drbolick]

This worked for me and definitely saved a lot of headaches.
Thank you so much!