Vray displacement modifier and motion blur turns an object black.

[GranetDI]

Hi,

Max 2012 Vray 2

I have a problem whereby I have an editable mesh which has a pointcache, a turbosmooth and a vray displacement modifier (2D displacement). Using a standard Max camera. If I render without motion blur all is good. If I render with motion blur some parts of the object render black. If I turn off the displacement it renders fine.

I have tried turning off the various modifiers and have isolated it as a combination of the displacement and the motion blur.

Has any one come across this and is there a known solution?

Many thanks in advance.

Regards

Grant

[Morbid Angel]

can you show us a part of your render?

also are you motion blurring between frames? i.e. have you tried with duration of .5?

[GranetDI]

I can't show you right now, I am rendering at duration .3.

Interestingly using a Vray physical camera it is not a problem. But due to our pipeline that is not an option. So it is directly related to the 3DSMAX standard camera.

Regards

Grant



Cheers

[vlado]

What are your motion blur settings - interval center, duration?

Best regards,
Vlado

[GranetDI]

Duration 0.3
Interval Centre 0.0
Bias 0.0
Subdivs 6
Prepass 1
Geometry samples 2
Blur particles as mesh NO

[vlado]

Then try setting the interval center to 0.15; maybe the physical camera works because it sets the motion blur interval entirely within a frame.

Best regards,
Vlado

[GranetDI]

Thanks for that,

I'll have a look at that and see what happens.

The geometry, which is the only piece in the scene that is affected, is very angular, a bit like a 7 pointed star, so I think it is possibly flipping some normals or creating some intersections that are not happy wen displaced.

I'll keep you posted and when I get the chance I will post a cleaned up scene for you to have a look at.

Really appreciate your participation.

Many thanks

Grant