Vray Hair Questions

[ruffstuff]

I've been using 3dsmax's buffer render for about 2 years and I have gotten some great stuff out of it for fur, but for longer hair I'm checking into using vray with max's hair tools.

My first question is to ask why using the MRprim option (With tip fade off) is slower than just using geometry?

2- How do I change the vray settings on the hair- not included in gi, motion blur ect. The problem I have is that I turn the surface that generates the hair to no render and then the vray settings are not editable?
3- When using geometry, how can you have the hairs pick up their colors from the surface that creates them?

Fred

[vlado]

The "mr prim" mode uses less memory and allows you to render more hair; it uses a specific hair shader to produce more realistic results; and it has optimizations to speed up rendering with the irradiance map and the light cache. The hair in "mr prim" mode has no motion blur by default - you need to set it to "object" in the node properties of the emitter.

Best regards,
Vlado

[signet]

Hi Vlado,

You say that the MRPRIM uses a specific shader. Is it possible to apply a shader to the hair rather than just maps?

does the mr Parameters and apply mr Shader respect the Vray shaders?

Thanks

Mike

[vlado]

Currently you cannot apply a different shader to the hair; the textures specified in the "Material Parameters" rollout of the Hair&Fur modifier will work fine though.

Best regards,
Vlado

[signet]

Interstingly the Motion Blur is still a problem for me when using MRPRIM.

Without the Object mode ticked in the properties the fur gets left behind.

With it on, its much better but still gets left behind when objects animate from stationary to moving over a few frames.

Increaaing the geometry samples has no effect. However to get the object to appear in the middle of the fur when its moving or starting to move I have had to decrease the interval centre to .25.

Any ideas why it doesnt just work?

[vlado]

Hm, do you have a sample scene for this? I'm pretty sure I tested this, but I may have missed something.

Best regards,
Vlado

[signet]

after some more testing with the VRAY phsyical camera without using exposure but with using the shutter to control Mblur it seems to be fine in early tests.

I will keep testing and set some renders going tonight to see if the problem re-occurs.

Thanks
Mike

[signet]

Hi

thanks for looking into this


render frame 1.

Currently the Motion Blur is turned off in the render dialog camera. As the last render i did was through the Vray Phys cam.

http://dl.dropbox.com/u/589453/Simple_Mblur_scene.max


Thanks again,

Mike

[vlado]

Ok, I see the problem. The hair is always calculated as if the motion blur interval starts at the frame boundary. To match the object motion blur, just make sure that the motion blur interval starts at a frame boundary too (e.g. if the duration is 0.5, the interval center should be 0.25). I've made a note to fix this too.

Best regards,
Vlado

[signet]

cool great.

But the Phys Cam stuff just works right then?

thanks
Mike

[vlado]

Yes, the physical camera always starts the motion blur from a frame boundary.

Best regards,
Vlado

[vlado]

I've had a look at the file; it appears that the Hair&Fur motion blur is controlled from the respective settings in the Hair&Fur render effect, and do not take in consideration the V-Ray motion blur settings. So you will have to play with these a little bit to get it right.

Best regards,
Vlado

[signet]

Even though those settings are greyed out when using MRprim?

Would they need to be changed before setting the rendering option for the Hairs?

[vlado]

Yes, the hair uses them even though they are greyed out. Just switch to "buffer" mode, adjust the settings, and return them back to "mr prim".

Best regards,
Vlado