image based motion blur in Vray

[kpavlov]

Is there a way to use motion blur in Vray so the rendering times are no more than 10-30% longer then without it.
Searching this forum I found that 3dsMax image based mblur works fine, but it doesnt work for me.

Rendering/effects/mblur, but it doesnt work.

I made animation of walkthrough of apartment and without motion blur it isnt what I expected.
Any sugestions, thanks in advance.

[cpnichols]

Re: image based motion blur in Vray

Rendering/effects/mblur, but it doesnt work.

That should work... I have tried it many times.

Also, if you want to try to do 3d motion blur, a good hint is to use simple level AA instead of adaptive. It tends to be much faster.

[kpavlov]

I dont know why I couldnt use it so I have merged all geometry and camera in new scene and it works now, but guess what,
there is a new problem, check two renders.
First is without and second with blur.
Looks like toon effects, but its not.
Max 6.0, Vray 1.47.03

[tammo]

maybe you have to turn on the velocity gbuffer in vray settings

[vlado]

Do you use any color mapping?

Best regards,
Vlado

[kpavlov]

Yes, I use exponental color mapping. I use it in all my interiors to make them look real. Please dont tell me I shouldnt.

[yeohyip]

Yeah, in order to use the render effect motion blur you need to turn on the velocity channel in VRay's Gbuffer rollout

[kpavlov]

Gbuffer object velocity doesnt help.

Here is the Max scene.
Just change extension of the file from jpg to rar and uncompress it.
I can only upload pictures to this server so this was little trick.

http://server2.uploadit.org/files/kp...lurproblem.jpg

[roppin]

I guess to solve it just for now. You could screen map the prerendered squence on to a matte and put on the motionblur afterwards. in that way I cant see any way for the strange thing to occure

Daniel

[kpavlov]

Sorry but I didnt understand what you mean, and how can that help me for animation.
You have a link to max file. Be so good and try it, maybe you'll solve my problem.

Vlado asked me do I use color mapping, well I do use it extensively, what about it?

[kpavlov]

Actually I have rendered one with linear color mapping dark 1.0 light 1.0 and its ok but if I use light 3.0, dark or higher I get dark edges. So the problem is in color mapping. Is there a solution for that.

Linear color mapping light 1.0, dark 1.0

[Morbid Angel]

kpavlov it appears that its not the color mapping. I have rendered your scene without color mapping but with motion blur, and got same result. By unchecking "work with transparency" option this black edges seem to dissapear. Try that and let me know if its good enough.

[kpavlov]

Thanks, you are right. Unchecking "work with transparency" works perfectly.
But I have noticed if you have "work with transparency" checked and color mapping is 1.0, for both dark and bright multiplier it renders ok so color mapping has some influence on this unwanted effect.

But what "work with transparency" really means. Does it mean that there is no motion blur for objects behind glass or something. What do I lose by checking that.

[Morbid Angel]

i have no idea...I hardly use 2d blur, mostly for objects that cant be 3d blurred, like fluids or advanced particles.

[Morbid Angel]

here is what help has to say about it:

Work with transparency—When on, motion blur is applied to objects behind transparent objects. When off, objects behind transparent objects receive no motion blur. Turning off this toggle can improve rendering speed. Default=on.