Rendering Glass with trasparency

[Baptista]

[IMG][/IMG]

I saw that from a arch collection model and i was wondering how you can render a glass object which is transparent so when you put it in front of something you can see the behind of it.I know for sure that its a png format and not a jpg.
Can someone tell me the settings to have that result?

[Thad]

not sure i follow

do you want the 3d model to have a material transparency, or do you want the final saved image file to keep the transparency automaticly for you to insert another image behind it on and image editor or whatever ?

if its the 3d model material, what software are you using?

[Perversonality]

You can add a mask layer to a PNG which defines the transparent parts, something you can do with any 2d editing app that supports PNG transparency

[Baptista]

its the second part Thad,i want the final image(render)from max to keep the trasparency so i can put it on photoshop and i will be able to see what is behind the trasparent material of the model.

Perversonality i am pretty sure that max does that since the image that i found was a max render with no modifications from a 2d application

[Perversonality]

In the render dialog select save file from Common > Render output and then type in a name with a .png extension. Before you hit enter, click the setup button and make sure that alpha channel is selected

[rockyourteeth]

Yeah, as far as I know, the default settings for a PNG save the alpha information. There are file types like TGA, but PNG should work fine, I use it all the time with alpha.

Also, if you're wanting to get something that is invisible, but still shows shadows (like if you want transparent shadows on the floor, but not an actual floor), then check out the "matte/shadow/reflection" material for Mental Ray. You can create a floor or a wall, and assign the material to it, and when you render, the object will be invisible, but the shadows on it will render. Can be very useful if you're wanting to create furniture to place over another image.

[Baptista]

i was busy doing something important and now i turned back to this project that i was doing.I did the render and still the glass wasnt transparent.i save the render as you told me Perversonality and the parts that i wanted to be transparent were black.Anyone knows what i do wrong?

[Perversonality]

Can you check to see what the mask looks like in a 2d app? That might point you towards a solution

[Baptista]

this is the object that i try to make the glass transparent.[IMG][/IMG]
when i export it as a png, the glass part is black because of the background color and when i change it to white color is getting white.so when i take the png and open it in photoshop i cant see behind it.the alpha maps shows the whole obj white.i still cant understand what i do wrong and how that guy has render it in that way

[Perversonality]

Ok, in Photoshop you should be able to take the alpha layer from the PNG and turn it into a mask layer. There's a layer option which is something like Layer Mask from Transparency that should do it (not got PS infront of me right now). You then have a layer for the render and a mask layer which controls the transparency

[DiogoM]

are u using vray? if yes you can check the "affect alpha" under the refractions options for the material, then u can save your image with any format that supports alpha (like .tga) and it should work