While I await an official Houdini ROP for krakatoa, I have saved a sequence that has a static number of points and can render. What I don’t have is the velocity of the points. As a kludge, I’m thinking I can setup a second PRT loader with a frame playback with T-1 and sample the point number position and calculate a velocity, assuming the points maintain a particle index properly. Before going down this path I wanted to verify that there is no At time context in magma and the possibility of one in the future.

There isn’t right now, and I am not sure it is feasible to do it on the stack as the particles of the current frame are coming up the stack. It would be hard for Magma to ask for a different time unless the PRT Loader had already pre-loaded both. Thus, using a second PRT Loader is pretty much the equivalent, and what I would have done in your place (in fact, I have done this in the past).

Elo,
just to clarify you have the velocity in Houdini,but its not exported to prt so you can use it in Krakatoa?

I assumed it wasn’t, but turns out it had a v channel! But this goes to another problem, Conrad Wiebe has downloads for exportsers up to houdini 13. We need this updated to 14 and 15.

Hi Oatz,

While we do plan on updating the official exporter that you mentioned, it may still be a while before we get to this.
In the mean time, there is a 3rd party plugin which says it works with 14 and 15. I haven’t used the plugin myself, so I can’t speak to how well it works, etc, so of course, use it at your own risk.

Probably it wont work,but could it be that you have the velocity channel,but its not called velocity but its simply v as in Houdini,so if you type v in the input channel maybe it exists?I think there was similar problem with Naiad before.Could be wrong tho :>.

There is also the Particle Data Viewer to see what channels exist in a PRT Loader (or any other Krakatoa-compatible particle object) and what the values are…

I have used that PRT_ROP and it does work - put it into your /dso folder in the Houdini installation directory and it will be in your /out level. You do need to rename v to velocity, this rop is setup to do this by default but the gui has parms to rename what you want to export each attribute as.

I found the renaming options to be very helpful and robust. Would use again. * * * * *