Alpha Channels/Maps

[guitarboy]

G'day, i fairly new to the 3d scene and have been having a little trouble getting nice backgrounds in my renders, and have been told to try using a alpha channel/map for my back when i render in max/vray and then move that render into photoshop and place my background in there.

 

My question is how do i actually get an alpha channel/map in for my background? and are there any other special things i need to be aware of besides that i need to save my render as a .tiff file format or similar in order for the alpha to work?

 

many thanks

[Horhe]

My question is how do i actually get an alpha channel/map in for my background?

 

What you need to do is to get a render from your 3ds max without the background (without the map that you have in your enviroment slot - either a image file or just plain color). The rest is done under PS as you correctly stated.

 

and are there any other special things i need to be aware of besides that i need to save my render as a .tiff file format or similar in order for the alpha to work?

 

many thanks

 

Yes there are. Firstly you do not save your image as .tiff. That'll do you no good. The file extension that seperates your scene's models and the background is the .png, which you will obviously find in the save image rollout menu.

 

In more detail, what happens when you save your render as .png, you get an output of your render with the enviroment or (background if you prefer) transparent. So when you load it up in photoshop you will have the image in the layer without the background jus like i said - transparency.

 

To input a background, simply place the recieved render on a layer above the backdrop image, so that the transparent bits of the image show the map.

 

Have fun

[guitarboy]

Wow, thanks for such a quick and in depth responce.

 

so if i just leave my render environment as the standard black, and save my render as a .png, that should work?

[Horhe]

so if i just leave my render environment as the standard black, and save my render as a .png, that should work?

 

You can leave your render enviroment any color you like, black yellow brown or a bitmap if you like. Its not taken into account when outputting as .png, but probably is with global illumination calculations and reflection/refraction unless you are overiding them with a map somewhere else in the gi settings.

[guitarboy]

AWESOME, thanks so much, i cant wait to give it a go. Your a champ

[guitarboy]

i just tried it out and it worked perfectly, thanks heaps again.

[Horhe]

No probs glad i could help, post it up when youre done

 

cheers mate

[guitarboy]

No worries, i just need to find some decent backgrounds. Do you guys get them off the net, or take your camera places and take your own pics, or something differnet again?

[guitarboy]

Gday, ive just moved my render over into PS, but ive noticed ive lost all my reflections in my window doing things this way, is that meant to happen, and is there a way around it???