Make the VraySky background invisible keeping glass reflection

[Stephan Dupont]

Hi,

 

I 've made a render with Vray and I want to put a background image using Photoshop. I know that I have to save my picture on .png to make the vray sky invisible but with this scene, it doesn't work, maybe because there is a glass with reflection. I want to keep this reflection on my background final image. Do you know how can I do ?

 

Thx a lot !

 

[Francisco Penaloza]

Hello Stephan,

actually, there are many ways to approach this 'issue' and this will be bread and butter for your CG work so I would recommend you to research and read all the option I mention here and I am pretty sure there are more.

Firs option as mentioned is if you are using VRay Sun/Sky saving as PNG, TGA, Tiff, EXR or any other image format that support Alpha, will do the trick, having said that be sure that your transparent materials have the affect alpha activated. otherwise, they will render black on the alpha channel.

Another option is to save Matts or passes. This can be a mix od Material ID or Objects ID. with this you can select in Photoshop or any image processing software what areas to replace. When you work with glass, you may also need to create a reflection and refraction pass to put back those as need it in your windows or transparent areas.

Other option can be replacing the background inside 3D Max, for this, you could replace the environment background image on the rendering window, but be sure to place the VRay sky on the GI overwrite in the VRay settings windows. There you could also Overwrite the background if you rather use that, you'll see that you can use one image or shader as GI source and other only for reflections.

 

You can also use the VRay Dome light to create an IBL system (Image Base Lighting), here you could use the same image as background or hide the done and use the default 3D Max environment or use the VRay settings panel options.

 

as mentioned earlier you have many options, you can choose what fits better for your scene.

Best luck.

[Stephan Dupont]

Thank you very much Francisco for your answer !! It was the solution, I add VrayReflection and VrayRefraction in the render elements setup . Thx a lot !

[Stephan Dupont]

But now, I want that reflections are more visible. Do you know how can I do ? Because on my final scene, reflections are here but not really visible, except in a black or white background...

[Francisco Penaloza]

You can use the VRay reflection or VRay raw reflection, this later will be more strong since it is not mixed with the other passes.

Then in any post-processing software such Photoshop you could mix them on Lighten, screen or even color dodge if that fits your mood.

 

The raw pass will be more visible in any of this modes, but you'll have to manually adjust the color to make it fit better the scene.