Alpha Channel Accuracy

[christosviskadourakis]

Hello there.

 

I want to use my alpha channel to change the background of my rendering. However, I found out (later in photoshop) that the accuracy of the alpha channel is not that great. I had to manually refine the edges of the alpha channel image, otherwise there was a white outline on the final image. The problem was more obvious on the areas that I have vegetation (trees) with opacity maps for leaves. But it was actually everywhere. For instance, on the edge of a wooden fence.

 

Any idea how to avoid this? Thank you!

 

Christos

[luisgalindo]

Are you rendering with an image in the background? that can be part of the problem, I always render with a black backplate.

[christosviskadourakis]

There is an image in the background because I use hdri image for lighting (so it comes with an image). Are you putting a black plane invisible to lighting calculations?

[luisgalindo]

If you are using a vray dome light with an HDRI just make that light invisible and be sure the max environment background is black.

 

If you are using an HDRI directly into the max environment background map clear it from there and use it in the environment tab inside vray settings.

 

The idea is to use a black color as background in max.

[christosviskadourakis]

I use dome vray light. I am aware of the invisible choice but for some reason I had the hdri image on the 3ds max background (really no idea why cause I dont do it).

 

Thank you, I will check it!

[luisgalindo]

No problem, let me know if that worked.

[christosviskadourakis]

It seems that it renders in white background...I have a vray dome light (hdri) and a vraysun, both ticked invisible. 3ds max background black color. Any idea why?

[Corey Beaulieu]

Did you put any maps in your Environments Override section of the Render Settings? Be sure those are unticked as well- all of them.

 

It could also be that have more lights than you think. Check your light lister.