Render Particles Tweet

[Hesekiel2517]

Hey Paul,

i have a lot of fun experimenting with Storm the Granular Solver, but encountered a few issues. First of all Replicators with changing Particlecount won't render Motionblur. Is this going to be a Feature in the Future or is it impossible to have it in Modo? Exporting the Animation to Octane Standalone works but creates huge Files. For Example my Source Alembicfile for a 50 Frame Animation ist 150MB but the resulting Orbx is 900Mb in Size. This and the long time to export makes this unusable in my opinion. Could this be improved?

Thanks in advance!

[face_off]

I don't think there is an easy solution for this. In theory, Modo should return a "motion vector" for each particle, which would resolve the issue, however the Modo API doesn't seem provide this, so the other two solution are 1) export the animation to ABC and load into Octane (which you have been trying), or 2) somehow keep the same number of particles each frame (probably not easy), or 3) have the plugin load the previous frame and the current frame for each frame to determine a motion vector (would double the load time of every scene). In theory, ther Modo Render Cache is also meant to provide some solutions in this area, since it is meant to provide motion vectors, but I have a number of bug registered with Foundry on this as it is not working correctly. If the Render Cache bugs are fixed, that would provide the best solution.

Paul

[Hesekiel2517]

Thank you for the quick answer! Mhmm, would it be possible to automatically scan the Pointcache and generate the missing Particles for every Frame? For example they could stay at the origin with zero scale until they are needed. Also your suggestion with the 2 additional Frames sounds better than no MotionBlur at all.

[face_off]

Thank you for the quick answer! Mhmm, would it be possible to automatically scan the Pointcache and generate the missing Particles for every Frame? For example they could stay at the origin with zero scale until they are needed. Also your suggestion with the 2 additional Frames sounds better than no MotionBlur at all.

I'm not sure where you would "hide" the missing particles, as when they enter the scene they would motion blur into the point of entry. Sorry I haven't been able to offer a reasonable solution. Foundry are aware of all these issues, hopefully at some point the Modo API will be enhanced so that it makes what you want to do possible. In the meantime, I would suggest splitting your scene 2 scenes - being "moving bits" and "non-moving bits", then export the entire simulation for the moving bits, and just the first scene for the non-moving bits. This may (or may not) save you some time over exporting the entire simulation).

Thanks

Paul

[Hesekiel2517]

Hey Paul,
i just have to render particles again and have (of course) the same issues as last time. So i have some new questions

Is it possible to export just the particles from modo and render them in octane as spheres? Octane does seem to support this, but i can't get it to work with my alembic files from modo
Modo 14.1 is released today are there some fixes which enables you to enhance particle rendering?

Edit: It works with particles from Storm, but not with modos. Are ther any tipps how to export particles as alembic? This would be a nice workaround (via a proxy) as the particles are separate from the scene and render with motion blur. Would it be possible to automatically bypass modo and feed the alembic file directly into octane?

[face_off]

Is it possible to export just the particles from modo and render them in octane as spheres?

I'm not sure, but I have already done a little investigating to see if this would be possible, and it might be - however assigning a material to the sphere would not be easily within the Modo plugin. An easier option would be to have an ORBX proxy with an Octane Sphere in it, and use that proxy as a particle Replicator Prototype. I would need to experiment to see if this is possible.

Modo 14.1 is released today are there some fixes which enables you to enhance particle rendering?

Not sure - I will check the Modo SDK release notes. In general the SDK is enhanced on major Modo releases.

Paul

[face_off]

I'm not sure, but I have already done a little investigating to see if this would be possible, and it might be - however assigning a material to the sphere would not be easily within the Modo plugin. An easier option would be to have an ORBX proxy with an Octane Sphere in it, and use that proxy as a particle Replicator Prototype. I would need to experiment to see if this is possible.

I tried this, and adding a Geometric Primitive->Sphere connected to a Geometry Out node in an ORBX file successful rendered as a prototype to a particle replicator in Modo. However perhaps you are referring to the Octane Mesh A_SPHERE_* attributes for a different Octane Sphere? I could not find any documentation on this feature. It appears to have been added sometime around Octane 3.00, but rarely used? If you find any info on it, let me know and I can investigate further.

Paul

[Hesekiel2517]

Hey Paul,
i don't think i understand what you mean. My Goal is to render Particles with Motionblur. Your Octane Plugin can do this but not if the particle count is changing. It's possible to export via the save Animation command, but this creates unusable big files. So I'm looking for workarounds.
I also testes Particle Alembic Files from Storm (Granular Solver) and it's possible to load them in Octane Standalone. Octane takes the Particles and renders them as Spheres. This can be used as a Proxy in Modo. So you have Particles with Motionblur in the Modo Plugin.
What i'm asking for is to make this automatic. So that Modo does the Proxy step and bypasses the current limitations.
Also i could not get this to work with modo particles. They simply won't show up in octane if i load a alembic exported with modo. Do you have any idea how this can be solved?

[face_off]

Hey Paul,
i don't think i understand what you mean. My Goal is to render Particles with Motionblur. Your Octane Plugin can do this but not if the particle count is changing. It's possible to export via the save Animation command, but this creates unusable big files. So I'm looking for workarounds.
I also testes Particle Alembic Files from Storm (Granular Solver) and it's possible to load them in Octane Standalone. Octane takes the Particles and renders them as Spheres. This can be used as a Proxy in Modo. So you have Particles with Motionblur in the Modo Plugin.
What i'm asking for is to make this automatic. So that Modo does the Proxy step and bypasses the current limitations.
Also i could not get this to work with modo particles. They simply won't show up in octane if i load a alembic exported with modo. Do you have any idea how this can be solved?

Octane will render Motion Blur with scatter nodes (ie. particles) if either

a) there is a velocity vector for each particle's transform in the scatter node for each frame in the timeline. This is not possible to implement in the Modo plugin, as it is not possible to get motion vectors of particles from the Modo SDK.

b) there is a scatter transform array for each frame in the timeline loaded into Octane (the plugin uses this approach if you have Kernel->Animation->Object Motion enabled) - however the constraint imposed by Octane with this method is that there needs to be the same number of transforms in the scatter at each frame in the timeline.

c) if there is a complete set of vertices for each frame in the timeline for all the geometry that needs to have motion blur rendered (so that Octane can use the previous and next frames vertex positions to calculate the motion blur). This is the approach that is used when you export from the Modo plugin to ORBX, and is why the ORBX filesize is so big. Can export to ORBX with only the moving objects in the scene, and then save the non-moving objects as a single frame to ORBX and then merge the two in Octane Standalone.

Does that help formulate a solution to your problem?

Paul

[Hesekiel2517]

Hi Paul, thank you very much for your effort, but it doesn't really help. I think i will continue loading the particles in Octane Standalone and bring them into Modo via a proxy, or just use VRay for this kind of work.

Edit: BTW do you now how VRAY is able to do this without any problem? Aren't they using the same API than the Octane Plugin?