3DS Max 2015, Vray 3.0 & Photoshop Alpha channel issues

[danielclark]

Hi All,

 

As I am relatively new to Max, Vray & PS please bear with me for the lack of knowledge.

 

I have created an architectural model in Max and used Vray for the texturing etc. and decided to render out the 2 separate images, the background with trees and the foreground with the model in. I then saved these as PNG files in order to retain the alpha channels ready for photoshop but before doing so looking at attached photo 1 you can see black transparency in the glass railing around the balcony. Sorry for the small confusing image, sick and tired of rendering this multiple times, photo 3 shows better elemental relationship.

 

I think the issue is down to the fact that behind this glass railing is another glass window, then an interior wall and then an exterior wall and that Max is getting completely confused with the alpha channel in that area.

 

Basically the results I am getting is within photo 2 where you can completely see the whole background image through the model, it is rediculous.

 

Like I say I am a newbie so I do not know if this is correct but I attempted to add a colour correction map to the opacity slot of my glass material and the results are in photo 4. Transparency was reduced but it has just caused a more dull effect and certainly not what I am looking for as I need a solid wall behind. (If it is of any use Photo 3 also shows glass material parameters).

 

As this is my first ever thread, I would be greatly appreciative of any help in resolving this matter.

 

 

Danny.

 

http://postimg.org/image/toxjo25hx/ (Photo 1)

http://postimg.org/image/4wxxgtob9/ (Photo 2)

http://postimg.org/image/n4zcvggut/ (Photo 3)

http://postimg.org/image/uwg2u0l05/ (Photo 4)

[braddewald]

It looks like you have some objects' refraction affecting the alpha channel and some aren't. You can also go to each object's vray properties and explicitly change their alpha contributions.

 

From the V-Ray Help File:

 

Alpha contribution - this allows you to control how the object will appear in the alpha channel. Note that this parameter does not require the object to be a matte object - this parameter has an effect on all objects. A value of 1.0 means that the object will appear normally in the alpha channel. A value of 0.0 means that the object will not be present in the alpha channel at all. A value of -1.0 will invert the alpha of the object. Note that turning an object into a matte object does not change its appearance in the alpha channel. You need to explicitly change its alpha contribution.