Vray Voloume Grid- Fumefx

[KushKush]

Hello,
I'm having issue rendering motion blur with VrayVolumeGrid. I've simulated cache in fumefx with velocity channel yet I can't render motion blur for some reason.
Anyone can help?

[slavina.nikolova]

Hey,

The problem could be related to a couple of things.

Could you tell us which V-Ray are you using - V-Ray 4 or V-Ray 5, and which is the exact V-Ray version you have installed? You can find the V-Ray version in the Render settings window → Settings tab → About V-Ray rollout.

If you increase the Motion Blur Multiplier from the Rendering rollout of the Volume Grid, do you still don't have any Motion Blur?

Do you see Velocity in the Cache File Content window?

What 3rd party channel mappings are you using? Different applications use different channels and names for them. When loading f3d/ vdb files, Phoenix FD tries to automatically make the conversion to the supported channels. If a channel is not mapped by default, you can manually set it to a channel from the ... button next to the Input Path, by choosing 3rd Party Channel Mappings. Could you check if you have the proper channels loaded in the Velocity slots?

Is the Motion Blur enabled in the Camera rollout in the V-Ray settings menu?

Are you using a Physical Camera and do you have the Motion Blur enabled, because when having a Physical Camera its settings override the V-Ray settings?

To verify if the problem is related to the Camera setup check if the other geometries, that are not Volume Grids, in your scene are rendering with Motion Blur.


Hope this helps!

[KushKush]

Hey Slavina,
Thanks for the response, I've attached a screenshot showing information you asked about.
- Vray 5.
- No, I've tried default 1.0 and 4.0.
- Yes, screenshot attached showing velocity x,y,z.
- Velocity channel seems to be assigned by default.
- It wasn't, I enabled it and no result while rendering from physical camera.
- I've enabled it and it looks like it does provide motion blur, at least for the geometry. I've also tested rendering from perspective and there is a motion blur on geometry but looks like it has limited effect on VVG.
My question is which motion blur parameter is relevant for VrayVolume grid? Vray settings MB, VrayVolmueGrid MB, physical camera MB?

[slavina.nikolova]

Hey,

The Physical camera Motion Blur overrides the Motion Blur of the V-Ray settings MB. You can control the Motion Blur of the VVG through the MB multiplier in the Rendering rollout.

Could you try increasing the MB multiplier in the Rendering rollout to something like 100?

Also, I can see that Velocity Y and Velocity Z are swapped, could you set them in the correct slots and see if that will help?


Thanks!