alpha grayscale problem, help

[3dSol]

Hello guys & girls

 

I am doing an animation of this type for the first time

It’s a diamond ring that rotates 360 on its z axis

The client will take the animation into after effects and replace the simple black background with something else

I am rendering in vray to get nice materials, BUT he requests that I provide him with alpha channels for him to work on that, my problem is that the alphas I provide are B&W and he says that the transparency of the diamond should produce a grayscale in the alpha for him to preserve the reflection

I’m new on this, I’ve only used alphas for opacity trees and such so I don’t know if the deal is the vray material that has a 255 refraction or if a MAX material will give this output as a grayscale in the alpha

Please if anyone could give me some pointers on how to solve this

I have to have it done by tomorrow and the animation is taking 4 hrs. already

 

Thanks much

 

3dsol

[Devin Johnston]

Save your output out as a TIFF file, you will be prompted to "store alpha channel" this will imbed the correct alpha information into the Tiff file and you can access it through After Effects.

[3dSol]

thank you maxer

i did that and i have a question about materials:

 

VRay transparency or refraction set to 255 will not produce a grayscale alpha

standard max material with opacity below 55% will do that

 

is there a way to get that grayscale in the opacity produced by a Vray material?

 

thanks

 

3dsol

[Devin Johnston]

Sorry I can't help you there I don't know anything about Vray.

[John Dollus]

All you need is an alpha pass. Why waste time trying to get it with vray?

Just run an alpha sequence through scanline. You will be done in minutes.

[3dSol]

thank you so much for the reply

 

i save the file as a .tga so i get 2 files, the color, and the alpha

 

i made a glass looking material with a standard max material and it provides a grayscale in the alpha, BUT it doesn't look good as a diamond in the color render, the VRay material does look good but does not put out the grayscale in the alpha

 

alpha pass? don't know how to do this (blush)

 

now im thinking if its a good idea to render the diamond for the color file with a VRay material and make another render with a MAX material to get the grayscale in the alpha, but i dont know if the correct reflections or transparency will correspond for the person who wants to use this in after effects.

 

thanks again

 

3dSol

[John Dollus]

1. Render out your main render pass unsing Vray (sounds like you have already done this).

2. Switch to scanline and put on your scanline material that gives you the alpha you want (sounds like you have this already as well).

3. render a scanline sequence but when you specify the TGA file type and image location, a dialog appears with the options for a Targa file. Right under the Compress and above the Pre-Multiply options is a check box for Alpha Split. Turn this on.

This will render out two image sequences. One will be the color pass (discard) and the other will only be an alpha map sequence.

4. Burn both sequences (vray and alpha) onto whatever media they want and they can load the alpha sequence into After Effects for use in replacing the background.

 

 

The alpha pass is for transparency only so if your scanline material gives the same level of transparency as you would expect from the vray material, you are fine. Also, they can adjust the amount of transparency in after effects anyway by manipulating the levels of the alpha image sequence.

It would be great if you could render out a specular pass from Vray as well in this case but I don't know if that works in 1.5.

 

Good luck!