Vray Instancer ID and tyflow

[mathieu_boch]

Hello,

In our pipeline we make some simulation in tyflow with proxy, and export in abc point cloud to have an quick loading scene and viewport usable. We load it in a vray instancer and replace particles by node. But when we set the good sim and export with shapeID, custom float, or any, I can't redifine the same shapeID with the only option that you publish, the particle interger. I wrote @ tyfow and they said that you've already patch it a long time ago. Can you please tell me the good practice to set the vray instancer that respect my tyflow sim with exactly the same shapes.

thank a lot for your answer.

[hermit.crab]

I semi-understand the issue. You wish to export a particle cloud with certain particle ids and you wish for V-Ray to read those particles and instance geometry in an identical seed? Could you attach a simple scene so I can get a better understanding?

[mathieu_boch]

Okay , you'll find attachements, and if it's not understandable again, ask me

[Joelaff]

I have not tried it but I do wonder if using PRT files with IDs might work, rather than Alembic.

Use the Phoenix simulator to load the PRT files. You can try the Phoenix PRT Reader, but it has issues with motion blur in some uses (should only affect velocity vectors on the particles themselves, which likely doesn’t matter for tree pivot points).

Of course the PRT Loader from Krakatoa is the gold standard. Though I don’t believe there is a 2024 version if that matters.

[Joelaff]

Note also that you could just use TyFlow itself for the instancing... depending on your needs of course. It can be set to use instances or render as a mesh.

Also Thinkbox Frost is another instancer that could be an option, or Forest Pack. In the commercial world often our deadlines are so tight that we just have to try a bunch of tool until one works, because we don't have the time to troubleshoot

[Joelaff]

I was having trouble getting this to work other than by using TyFlow as the rendering tool rather than VRayInstancer.

Interesting discussion here:

https://forum.tyflow.com/thread-1623...articleinteger

Sure would be nice if Chaos would allow VRayInstancer to read other channels to use as the shape ID, rather than just particleInteger.

I suppose you could write PRT files from TyFlow and then use Particle Flow with the Krakatoa PRT nodes to load those PRT files and add the particleInteger there.

[mathieu_boch]

The reason that we need the feature is to replace Forest, because we can't trigger animation on few items. And we don't want to install phoenix or Krakatoa, just for the PRT loader (the tycahce can read PRT). This feature is not in vray scatter as well. Tyflow is very powerfull in this situation , but if we put our trees in it, our scenes become very long time to load. The best performance way is reading the shape ID in a vrayInstancer.

[hermit.crab]

I think I understood what is going on. The particleInteger node was added so that pFlow scripts that export a particleInteger channel could be read. So as to keep consistency between instanced geometry (what you would like). I presume tyFlow could also export such a channel (through the script operator), however, I am not experienced in its API and cannot write you one. I'll ask around if somebody could help, though.

[Joelaff]

I think I understood what is going on. The particleInteger node was added so that pFlow scripts that export a particleInteger channel could be read. So as to keep consistency between instanced geometry (what you would like). I presume tyFlow could also export such a channel (through the script operator), however, I am not experienced in its API and cannot write you one. I'll ask around if somebody could help, though.

According to Tyson here it sadly cannot.

https://forum.tyflow.com/thread-1623...articleinteger

Perhaps this has changed. I tried mapping some other values to particleInteger, but didn’t have any luck.

[Joelaff]

What if you were to export one Alembic particle file for each tree shape? Then your VRayInstancer would just instance one tree model per ABC file.

Or perhaps you could just break out specific IDs to their own files if some of them can just be random.

[hermit.crab]

FYI, I wrote to Tyler so we can synchronize the matter between the two software. I'll write back with more information.

[hermit.crab]

Turns out there's currently no way of matching shape instances between tyFlow and the VRayInstancer. The problem is that tyFlow does not support integer channels, but it does support float ones (which can be set through the "Custom properties" operator and also be used to distribute objects based on it). I've logged an improvement request for a new VRayInstancer mode - "By Custom Float Channel" (internal bug-tracker id: VMAX-13371).

[Joelaff]

That was what I found by trying it... Certainly easy enough to convert a float to an int Looking forward to it, thanks!