how to use the vraymtlwrapper??

[freak]

i just cant get any shadows with with vraymtlwrapper, i got the tick in shadow and affect alpha, and alpha contribution to 0(what is the differnece between 1,0, and -1 anyway?)....std mtl in the wrapper.....i asign it to a plane to imitate the effect on suurland's peuguot 307....i can do it without vray tho....but how can i do it with vray?>???

[RErender]

That setup should work, your not getting any shadows? Do you have a light in the scene? Are shadows turned on for the light? Are the shadows raytrace?

My bet is on the last one

[freak]

i use vray light

[freak]

even if i use max light..no shadows at all.....what object dou asign it to? the plane or the object that's casting the shadow??

[RErender]

It should be on the plane, when you applied the wrapper did you choose "discard" for the standard material?

[Eldar]

From what I've figured out on my own

alpha 1 will give you opaque alpha for that object. Object space will look white in alpha channel. If the object is transparent, you will get a grayscale gradient in alpha according to transparency. I haven't had a need to use this much other than special cases.

alpha 0 will make the object fully invisible in alpha.

alpha -1 will make the alpha of the object fully black where object is located (it will be transparent in compositing).. other objects that are physically located behind it, will be occluded.. meaning, it will burn a hole the shape of the object in alpha channel for any objects that are behind it.

In traditional matte setup situations, -1 is probably most commonly used for matching renders with live footage. Ground plane would be -1, and therefore invisible, with only shadows, reflections and GI showing.

In your case, I would try -1 setting with shadows and affect alpha turned on in vray wrapper material that is assigned to the object you want to receive shadows. Objects casting shadows don't need wrapper, unless they are matte objects also.

Hope this makes sense.

[freak]

thx ALOT ppl..i got it working now....lol...i change the color to black instead of default white to make it work...lol.....

[freak]

actually one more qesution...the object i am rendering is red & reflecting a hdri map....after the render is done . i found that the matt have redish shadows...i am using alpha contribution 0....how can i fix it so that the shadows wont be redish...

[egz]

You can't. Unless you render a separate shadow pass (hide the main object from camera to get this) and desaturate it in your compositing software.

The reason the shadows are reddish is that matte objects also catch GI bounces from your object. When you composite this the reddish shadows will most likely look more real than desaturated shadows.

[freak]

thx alot egz...btw..i love ur car and glass mat

[egz]

Thanks

For those people that are having some problems with them, I'll try to get a new version out late this week.