URGENT mblur, render, hair fur solution needed! PLEASE

[Morne]

Hi all

I have motion blur enabled on my VRPhysCam with 8 samples.
Bushes have VRay materials applied. Pure geometry, no opacity.
I render my scene with VRay and I get this:
scene.tga
As you can see the grass is messing up around my trees.

Now if I render again with VRay excluding the grass, then render the grass only with scanline and comp it into my scene, I get the excact same result!
grass.tga
But if you look at the grass only version, all seems fine!

I tried to exclude the bushes from motionblur by selecting VRay prop and deselecting "default mblur" and set samples to min which is 1. Not sure if that helps as it seems to get same result

Please Help this is rather urgent!

Running Max 2009 64bit, VRay 1.5SP2, Vista 64bit, 8GB Ram

[Morbid Angel]

it could be a comping issue, did you check your alphas to be correct? in any case, for you I would suggest not to use physical camera, in some conditions it maye not produce correct results with stuff like grass. But if you render them separatly it should work...

[vlado]

I think it might be happening because of a difference in how V-Ray and the hair calculate the z-buffer. I've looked into it and I may have a fix for it; if you like you can email me to vlado@chaosgroup.com. You'll need to use a regular perspective camera though, not the physical one.

Best regards,
Vlado

[vlado]

Hm, it looks like the Hair and Fur render effect does not use the z-buffer... then I don't know what it might be; if you wish you can get us the scene to vray@chaosgroup.com for investigation. In any case, you can first try using a regular camera.

Best regards,
Vlado

[Morne]

scene file sent to Vlado

Hm, it looks like the Hair and Fur render effect does not use the z-buffer... then I don't know what it might be; if you wish you can get us the scene to vray@chaosgroup.com for investigation. In any case, you can first try using a regular camera.

Best regards,
Vlado

Hi Vlado I sent you the scene file in an email with subject "URGENT mblur, render, hair fur solution needed! PLEASE"

I tried with standard cam and still same story. I also tried collapsing bushes to mesh and still same story.

Best Regards,
Morne (DVP3D)

[Morne]

Vlado, switching off GI (brute force at the moment) fixes the problem, but obviously causes another problem as now the ligthing is really bad.

[Neilg]

If you do try and comp them in together, when the alpha channel cuts into the grass layer it's exposing a little bit of the flat place underneath on the BG pass. Problem is, your ground is blown out so it's giving you those sharp lighter edges.

Try using a texture on the ground that more closely resembles the final colour/brightness of your grass.


I've thrown it through combustion and masked out part of the FG to show what I mean. If the ground was darker this would look fine and be pretty much correct.

[Morne]

...
Try using a texture on the ground that more closely resembles the final colour/brightness of your grass.

If the ground was darker this would look fine and be pretty much correct.

Thanks Cubiclegangster, I'll give that a try and report back in the next 30 minutes or so...

[Morne]

That did the trick

Whoohoo Thank you very much Cubiclegangster! That did the trick!



Thanks!

Best Regards,
Morne (DVP3D)