Creating an Alpha map of specific things in max?

[AFK_Matrix]

Hi,

 

Ok what I want to do is render out my image with black windows so that I can add in the reflection in Photoshop. But I also need to render out an image that shows curtains in the windows.

 

I send my images off to another computer via the Net render so I can't send 2 renders off with the same name as it doesn't like this. So is there a way to create an alpha map that will just highlight my windows? At the moment I use a Render Element to create an alpha map so I can pick out the background to add skys etc. I just need an alpha map that just picks out the window glass.

 

Hope that makes sense.

[Chad Warner]

If your glass is it's own object, right click on the object, go to properties, change the g-buffer ID to 1, then under render elements, have it render the "object ID" element.

[AFK_Matrix]

Hi Chad,

 

Thanks for the quick reply mate. Ok I have found the Gbuffer ID in properties but I can't find the Object ID element listed in the Render Elemants tab in the render menu.

 

For your information I am using Max 7 with the light tracer lighting and the defualt scanline renderer.

[Chad Warner]

Strange. I don't have Max 7, but I have Viz2007 installed and I think it's the same build, and it's there. It's not called Gbuffer ID, but it's "Object ID"

[AFK_Matrix]

Yeah I do actually have Max 9 installed but just waiting for the IT guys to put the Max 9 Backburner onto our rendering machine before i switch to it. I had a look in Max 9 and it has it there so for some reason its not included in Max 7 . Guess i'll have to wait.

[Scott Erstad]

Great question. My approach has typically been to first do a save as and rename to Mod0x-select, then set up to render without maps, shadows or advanced lighting, ray trace. Then set all local maps to some gawdy color scheme and render out. Then in PS, use select by color to create my alpha maps.

 

This takes about 10 minutes and then I can select any material fairly easily, but not perfect like it sounds like this will allow.

 

Question... will this render elements approach take into account objects in front, such as RPC trees or cars or mullions (if glass)?

 

I will definilty test this out, it would be enormously helpful for anime - I dont have combustion.

 

Thanks,

Scott

http://www.andersonillustration.com

[Chad Warner]

Glass and mullions yes, RPC's, I'm not sure.