OTOY Forums

Hi I was told mb does not work with liquid (realflow, phoenixFD) because of changing amount of vertices every frame.
Do you think you can solve this one day or it is impossible to do? I think when big companies will use Octane 3 they would want motion blur for liquids.

Or the only solution is to render liquid mb like we render with 3ds max scanline renderer many passes to get one frame

Thank you

Does this mean that also motion blur for volumetrics like smoke won't be supported in V3? From what I've seen of V3's features for animated volumetrics you have to load a different VDB mesh for every single frame, I would imagine this would cause a similar problem.

The Houdini plugin can render this kind of scenes with motion blur because the host application supports vertex velocity vectors and expose this information in the SDK. In other packages, like in LightWave, it is not easy at all, because they don't support velocity vectors, or they don't expose the vertex velocity vectors information in their SDKs.

-Juanjo

juanjgon wrote:The Houdini plugin can render this kind of scenes with motion blur because the host application supports vertex motion vectors and expose this information in the SDK. In other packages, like in LightWave, it is not easy at all, because they don't support motion vectors, or they don't expose the vertex motion vectors information in their SDKs.

-Juanjo

Thank you

i hope new 3ds max 2017 will be able to do it. if we cannot have liquids, gases, flames with mb it will be a big problem. And I think over 50% octane users are max users
Can Otoy contact autodesk and ask them if they are willing to support vertex motion vectors in the future. I wonder how their iray does motion blur for liquids from realflow, etc

here is iray gpu renderer in 3ds max and it support motion blur just fine

https://youtu.be/K-9HqQS_F08

here is a response from lucid physics in 3ds max https://ephere.com/plugins/autodesk/max ... index.html

"Yes, that is a problem. Mesh needs to be sampled at sub-frame interval, in that case topology changes is not a problem."

If the host application doesn't provide vertex motion vectors, couldn't you calculate your own using the current frame's vertex positions and the next frame's?

profbetis wrote:If the host application doesn't provide vertex motion vectors, couldn't you calculate your own using the current frame's vertex positions and the next frame's?

It just works with constant vertex counts. Not fine for example a liquid's mesh or metaball mesh.

aoktar wrote:

profbetis wrote:If the host application doesn't provide vertex motion vectors, couldn't you calculate your own using the current frame's vertex positions and the next frame's?

It just works with constant vertex counts. Not fine for example a liquid's mesh or metaball mesh.

how were they able to have iray have mb with liquids

Thanks

coilbook wrote:

aoktar wrote:

profbetis wrote:If the host application doesn't provide vertex motion vectors, couldn't you calculate your own using the current frame's vertex positions and the next frame's?

It just works with constant vertex counts. Not fine for example a liquid's mesh or metaball mesh.

how were they able to have iray have mb with liquids

Thanks

I don't know it but most likely by a special function which gives velocity vectors. Because you can't follow a vertex on next frame. ID will change. Only way to do by a speed/velocity vector. Currently we have support in Octane for motion blur by speed vector. But we need to have a functionality to read this data. I don't know it on max but it's very problematic in C4D's sdk that's very limited and unproper for octane plugin's workflow.