Render Issue

[Anonymous]

Pls help me out. 

I'm working a scene with a Dragron in it. I have Motion blur on and I have Fluids in the scene. I'm also rendering with Vray. 

When I render the scene with the Fluids fire/Smoke) visible. Th sequence has a lot of grain in it. I also get this error (// Warning: [PhoenixSimPlugin] Motion blur without velocity channel will not work properly.) I don't know if this makes a difference, but i'm using maya 2016.

So, I'm wondering someone can tell me what's happening. 

Thank you very much in advance for you time. 

[J450NP13]

I recommend doing any motion blur in your compositing process instead of rendering it.  Remember...you will not be able to un-blur it once you render it blurred.

[Anonymous]

Thank you very much.

[pshwayka]

Have you enabled the VRay fluid shading quality attribute for your fluid? If not, select your fluid container, and at the top of the attributes panel, click Attributes->Vray and enable it. Some related settings will now show up at the bottom of the panel. Also, that warning is to remind you to add the Velocity channel on your Render Elements tab (VRay render settings.) That will create a velocity render pass that you can use for compositing. (I've never done a composite with a velocity pass, so you should probably investigate that based on your compositing software.)

[Jimb0]

Maya 2019

Vray:: V-Ray Next for Maya, update 2.1 (v4.30.01)

Goal:  Trying to get motion blur (or, in this case Motion Vectors) for moving fluids in Maya with V-Ray.

Following the clear instructions listed above.

1) Select the 3D fluid container

2) in the Attributes Window, click: Attributes --> Vray --> V-Ray fluid shading quality. Adding the Extra Attributes and Extra VRay Attributes rollout windows.

3) In the second window (eg. Extra VRay Attributes), you have 3 choices for Volume Shader: Auto, Phoenix FD, VRay Environmental Fog.  I feel like (in my case using Maya Fluids) that I should leave this set to "Auto," but I tried all three just in case.

4) At the bottom of the Extra VRay Attributes rollout window, set Full motion blur to:L (4 choices -  Disabled (default), Velocity, Blend, Velocity+Blend).  I tried them all.

But, alas, there was never a motion vector pass created (just gray pixels).

And just to be sure, I have motionblur, camera motionblur turned off in my Override->Camera Settings.

And, I have the following Render Elements being created for each frame of render: vrayRE_Z_depth, vrayRE_Shadow, vrayRE_Velocity.

But vrayRE_Velocity is gray with no vectorfield pixels rendering.

Is there something else I need to do in order to create motion vectors?

Cheers,

- Jimbo

[Jimb0]

PS -- After adding the Extra Attributes to fluidshape1, I not only did not get the motion vectors I was hoping for, but I received a new error listing in my Maya Script Editor:

"The dynamics evaluator must disable the evaluation manager due to these unsupported nodes
volume_emitter fluidShape1. Disable the 'dynamics' evaluator, or remove the nodes, to resume using the evaluation manager."

So, now that they have their extra Vray Attributes, it seems they are now "unSupported nodes" as well.