matte/shadow problem

[merendas]

I am trying to make just the shadow appear on the background using the matte/shadow material, but the plane always renders, and I just want the shadow on the background to appear not the plane.
I am tired of playing with the material settings and vray parameters.
What am I doing wrong?

heres the example

[Drewvian]

what are you using for a program? If it is maya I can help if it is 3ds max I can sorta give you a general idea of what to look at.

[merendas]

3d max 9 , forgot to mention sorry.

[Drewvian]

From looking at your picture it looks like you need to up the samples for your light.Cause at the end of the the shadow in your picture there is alot of noise. Which means that you don't have enough light samples going on there. Try messing with that first and then it should come out looking fine.

[Bob Marley]

I dont think you are answering his question Drewvian, he s after the transparency of the plane keeping the shadow.

Try using scanline render and you ll see it work just fine, as i dont use vray at the moment its gone be hard to help, i just found out the way to do it with mental ray, and it was a realy pain.

Otherwise if you wan tto stick to vray:
check google all the answers are their, here s a link I just found:

http://www.3dbuzz.com/vbforum/showthread.php?t=123276

[merendas]

i had tried the Vraywrapper too and no cigar the plane gets invisible but no shadows , with scanline didn´t worked too.

but i found this tutorial(its not exactly what i wanted since i suck with photoshop but theres no other choice)
http://jg3d.blogspot.com/2009/07/tutorial-how-to-make-shadow-matte-with.html

thanks for the help

[Drewvian]

oh I see what you mean. Sorry I misunderstood what you were saying. Are you trying to render the picture but keep the shadow but be able to get ride of the plane? if so then you may want to render them in different layers. Yeah what merendas link is what will be able to help you out for that.

[Fredddy]

I might be stating the obvious but have you enabled the plane as a matte object?
If not you need to right click on the plane, go to vray properties.
Enable matte in the Matte Properties and also shadows in Direct Light.
It best to use the vraywrapper material for this.

[merendas]

no problem Drewvian , yep i guess thats the only solution.

Fredddy , i changed the alpha to -1 , shadows and matte object on in vray paramaters , and alpha -1 on the material , i think i have all the paramaters fine?

[Fredddy]

Here is a quick test with the settings of the material and the vray properties of the plane.
1 vray light used for shadows.
Hope this is of use.

[merendas]

I inserted everything like you have and it still doesnt create shadows on the invisible plain.

I noticed that i dont have the "no GI on other mattes" box on my vraywrapper ,so i must have a different vray version than you , mine is "vray adv 1.5 RC3" , maybe its some kid of bug in my vray?

[Fredddy]

Yes, different version.
I'm using vray 1.50 sp2 with Max 2009.

[merendas]

thanks anyway :) , i guess theres nothing much to do about it

[robeltong]

i want render with alpha channel, and save .tga files, i need only object and shadow,but can not,it include plane