Hi I am trying to go recreate the filament advect example that you find in the documentation and I got stuck with the following menu:

Source Filaments -> bindings -> geometry subdata??!!!

The example shows that the node is looking at a geometry subdata in the POP object called Filament. I can't “geometry subdata” in the documentation, nor in the scene tree, so could anybody enlighten me on what this is and where I can set it?

Many thanks.

Richard

This is what is written on the “sticker”:

The Source Filaments node is used to bring new vortex filaments into the simulation every 40 frames. The new filaments are appended to the ‘Filaments’ geometry subdata on the POP object.

Where is the link to the example ?

Rob

the geometry subdata in the example is called “Filaments” and is appended to the pop object
you can see it in Details View so look for data named “Filaments”

but as the Source Filaments DOP creates that geometry it's really up to you how you name it (Just don't name it Geometry as that is by default the name of data containing the Particles)

so if you name it MyFilamentGeometry
then you have to use that name in POP Advect By Filaments/Dopdata parm
as well as Filament Solver/Bindings/Filament Geometry parm
so they all work with the same geometry data
and every microsolver you want to change or access that data needs to use the same name

Hi Thomas,

Many thanks for your reply.

Please correct me if I am wrong, so I just need to write Filaments (or whichever other name) in the tab, it is a bit like creating a group.

After I create that I just need to use the same name whenever it is necessary (as with a group).

Hi Rob,

The example is in the Houdini examples for Advect by Filaments or …/examples/nodes/dop/popadvectbyfilaments/AdvectByFilaments.otl

Thanks guys,

R

Hey guys,

I got that right by the looks of it, now I have a new problem: when I plug the filament solver into the second slot of my merge node Houdini crashes.

Any clues for why that may be?

I have attached the file in case you want to have a look.

Many thanks for your time.

Richard

when you create Filament Solver node, first rename Filament Geometry Parameter value from Geometry to Filaments (as you are using that name now)
and only then connect it to the merge node
because Geometry data contains just your particles so if the Filament Solver tries to use that geometry data as your filaments it may be causing crash as they are just points and filament solver needs edges

Thanks Thomas, will try that.

Got it right finally :?

That certainly seems to be the reason for crashes. I have to say that it is extremely sensitive to any situation where the solver doesn't find geometry it expects. For instance setting everything up (let's say identically as it in the sample file) and then going to the filament source and accidentally deleting it, or trying to switch it to different input shoots Houdini down every time.

It of course makes sense that it's not going to work without correct input, but one would expect and error rather that cold crash. I'm for example unable to use the shelf tool to create the filaments setup as it also crashes immediately. I suspect that it will be for the same reason.

I reckon some fail safe within the solver would be nice to prevent this.

Hey all,

I tried every combination of the data and bindings for the filaments to work. I cannot get any response from the solver. Can somebody please take a look and tell me what I'm doing wrong here?

Much appreciated