Motion blur (Object Properties) work with Vray?

[tvnguyen]

I'm new with vray. Before using Vray, I often set motion blur in object properties of my part. This Motion Blur works with Scanline renderer. But when I change to Vray renderer, it does not work. I don't want to use Camera motion blur because I don't want all moving parts get blurred.
I believe there is a way, but I don't know.
I appreciate your help.
Tam

[hermit.crab]

From what I understand, you wish to have motion blur on specific objects only. You can do that the other way around, activate motion blur for the whole scene (either through the Camera rollout in the render settings or through a Physical camera), and set a Motion blur duration of 0 to those specific objects through the V-Ray object properties.

[^Lele^]

It can be done like Alex suggested, or the other way around too.
Set moblur duration to 0 in the render settings, turn off camera motion blur there, as well.
Then for the geo which needs blurring, call up its v-ray properties (on the right-mouse menu) and turn on the override for blur duration (and in case also geometric samples, if the motion is curved.).

[Joelaff]

I always meant to test... is there per object mblur a multiplier (I hope)? Or is it absolute? If absolute frame duration why default to 1.0? (Makes sense if it is a multiplier. )

[hermit.crab]

I always meant to test... is there per object mblur a multiplier (I hope)? Or is it absolute? If absolute frame duration why default to 1.0? (Makes sense if it is a multiplier. )

The motion blur duration parameter in the V-Ray properties is exactly that; it uses frame duration rather than a multiplier, however.

[Joelaff]

Thanks for clarifying. Perhaps future versus could get a unit (frames or “f”) in there to remind the user. And it should likely default to 0.5f.

I’d still prefer a multiplier because that way I could still assist the motion blur fit the whole scene in one place (camera settings).

[^Lele^]

I’d still prefer a multiplier because that way I could still assist the motion blur fit the whole scene in one place (camera settings).

I hear you on this, but then the current case solution wouldn't work (as the global blur length is 0).
Explicit is fine, i'd think, especially as the props are standard user props and can be very easily iterated via MXS.

[Joelaff]

I hear you on this, but then the current case solution wouldn't work (as the global blur length is 0).
Explicit is fine, i'd think, especially as the props are standard user props and can be very easily iterated via MXS.

Not sure I understand how the global blur length is 0. If I enable blur in a vray camera it defaults to 180deg (0.5 frames) with a phase of -90 so the blur is centered around the frame.

Also, I guess that begs the question of whether or not the phase is still respected with regard to per object blur, and if the blur is centered around the same point in time as it is with object with the blur set at default. All Easy to test. I just always think of this stuff when I am deep in production with a BS deadline.

[^Lele^]

Not sure I understand how the global blur length is 0.

Hihi, it's the solution i proposed to the thread question, here.

I just always think of this stuff when I am deep in production with a BS deadline.

Ah! It's like the best of dreams. Happened to me all the time as well! ^^

[tvnguyen]

Thank you guys, specially Alex and Lele. Both of your ways work well!