another wrapper situation

[tambyra]

Hi everybody,

my situation is like this, as much as i have searched, very specific.
I'm working on a find an object game, and i'm supposed to make all of the 3D graphics. The thing is that i'm supposed to make it easy for the photo shop guy by making an empty scene ( only the basic room elements, without any objects that are supposed to be searched ) , an full scene, and the part that i'm having problems with, the only elements with their shadows scene !




i have tried lots of different vraymtlWrapper combinations, but nothing is working for me because i have to keep the light source and wall colors but they must not be wisable
I have read lots of tuts, tried them but i can't get it right,

Has anybody had a similar situation?
gamma is -1.0 and all the ticks are on....

any response is very valuable!

[svetlozar.draganov]

Would it be possible to simplify the things by sending us a very basic scene and explain us in details what exactly you would like to do and what exactly is the issue since we are not sure that we understand you correctly.
We are looking forward to hearing from you.

[vlado]

Do you need the shadows for each object separately? For for all of them together?

Best regards,
Vlado

[tambyra]

Hello,
yes i'm sorry i didn't reply yesterday , i updated to the latest version and im yet to try it again. I'm thinking of the easiest way of doing this and i think all objects together and their shadows would be great, it would be even more great if shadows would keep the colors
then i would save it in PNG and marge them in a fresh scene with no objects so they will later in Unity be made active
Because i am in a middle of a project i will try the new Update and post my new work....
i really appreciate the response and will update this thread as soon i try this
till then all best

[Syclone1]

The easiest way I can think of is make everything but the object you want to render a Matte object and render each one separately. Ive done this in the past which can be a little labor intensive but it worked...

[vlado]

Well, the best and most correct ways to extract matte masks is the one in this tutorial:
http://docs.chaosgroup.com/display/V...oving+Objects#

The first two sections, "Compositing basics" and "Compositing in 3ds Max". It requires two renders (for the "black" and "pure" images) in addition to the regular render, but works with any renderer, in all situations. I still have no idea how to make that work in a single render.

Best regards,
Vlado

[Shimakaze]

So pink!!!
If I understand you right and you just need a single picture of the background with shadows and no objects, then the simplest way I can think of is to just select all objects and go to properties and uncheck "visible to camera". That way they disappear from the scene while still casting shadows. You then end up with a single picture with just the background and shadows. If you then need just the shadows you could subtract a pass with just the background from that image.
If you want each individual object and shadow as a separate picture with transparency Vlado's method is difficult because you don't end up with transparent pixels since you have to add them to non-transparent pixels with blend modes. So you'd have to mess around with opacity masks and crap. (was in the same situation a couple of months ago and it is a pain.)

My number one on my VRay wishlist for years has been a single easy way to select an object and render it and/or the effect it has on everything else in the scene with a perfect alpha (non-multiplied vs pre-multiplies alpha issues aside). It's one wish I doubt I will ever get fulfilled :P

[vlado]

My number one on my VRay wishlist for years has been a single easy way to select an object and render it and/or the effect it has on everything else in the scene with a perfect alpha (non-multiplied vs pre-multiplies alpha issues aside).

That's exactly what that tutorial describes...

Best regards,
Vlado

[Shimakaze]

Yea but you still have to actually blend the picture into another picture, don't you? How would you go about removing the background altogether and replace it with transparent pixels?

[vlado]

Yea but you still have to actually blend the picture into another picture, don't you? How would you go about removing the background altogether and replace it with transparent pixels?

I would use the inverted "mask" image as the (premultiplied) alpha of the "object" image. That's all. (Note that your software would need to support colored alpha).

Best regards,
Vlado

[Shimakaze]

Hmmm interesting. I'm sure I tried that before and discarded the idea for some reason but not sure why. I just tried that myself and it does actually work. Sucks having to render a scene three times though so I still wish for a catch-all one-render solution But good to know this method works better than I remember!

[vlado]

Sucks having to render a scene three times though so I still wish for a catch-all one-render solution

Yes, there is that. I haven't figured out how to get the exact same result in one render though. The matte/shadow material does some assumptions in order to work and those are not always true, especially with GI.

Best regards,
Vlado

[tambyra]

I tried that before the update, and it didnt work, can u tell me if in your case the shadows are in color or gray? Now i just cant get the time to try it out, workflow and all, but i hope i will get some time these days, i will post all i learned here
thx for the reply

[tambyra]

hahaha yes, demands of the game industry, next room is all blue
yup i think i tried that also. But i still had some problems, dont remember with what because i tried hundreds of wrapper combinations...i will try and find time to do a new render with an updated Vray and post my findings

[tambyra]

Hi all, i finally got some time to do a test with the latest version of V-ray
It worked oh joy, the standard procedure , all background is wrapper mtl and all unnecessary objects are hidden in a special layer.
i didn't get any light spills or any unwanted shadows or gray areas.
Next step for me is to try and make the shadows colored...and i think i can achieve it by duplicating walls, so that ones have wrapper and others are just invisible so they could cast color
will try it in a couple of days when i get the time again
Thx all for giving some thought, i appreciate it