Rendering with alfa ? - another question, please view again!

[pimeto]

Hey there!
How can i set everything besides my object to be rendered as alfa in the image format TIFF for example ?
The situation is this. I have a ship that i have to render from 16 angles (you remember the sprites, games were made of back in the days). So studio that i do freelance for want the images to be with transparent background and now i am NOT a render guy at all and just cant figure how i can make it happen ? Is it doable from XSI or i have to go all the images in PS ?
It will be nightmare i think in PS because i have glow effect from the ships engine etc...

Thanks in avdanve for the help...!

[grahamef]

If I understand you correctly...

Set up a new render pass. Put all the other objects into a new partition, and apply a constant black with A=0. Render with Color Channel Clipping on the Framebuffer tab of the mental ray settings set to "No Clipping".

[pimeto]

Actually i found how its done. SImply select PNG file type, then go to pass options> slate and set the background to zero

[pimeto]

Hey guys, i simply can't figure it out.
Here is a render of my ship and some glow-lit parts on the ship. The ship renders as black silhouette because i need the neon lights for post production in photoshop later.
But, is there a way to create a pass to render the NEON lights but not to render the ship in this way. But yet to keep the ship covering the back side of the lights, so they dont show up at all if they are not directly visible ?

Here is a shot of what i mean.

[julius]

If I understand well your problem :

create a new pass and a new partition for the ship and put a color to alpha material on this partition. Like that, the ship will not be rendered anymore, but his silhouette will directly make a cut in the alpha. So, entire or parts of objects covered by the ship wont appear anymore.

[pimeto]

Hey man, can you explain about this color to alpha ? From the material editor, i put new material to the ship and then where is this color to alpha ?

[pimeto]

Well i found the none and pluged it in transparancy but still i see the back side.

[julius]

Here is an exemple :

Color to alpha applied to the cube : as you can see, you keep the shadow on other objects, but there is a hole in the alpha. The cube doesn't appear in the color pass, but still cut other objects.

[pimeto]

Dude, you saved my life man! Thank you sooooooooo much i can't express it in english
Thanks! Live long and prosper!

[julius]

you're welcome

[pimeto]

Hey Julius, its me again. With a question about if i can make this Color to alpha controlled with texture
As you can see in the photo im trying to make this obj with alpha texture but in the render it renders black where its transparent in the viewport.
How can i tweak it to render out the black with Color to alpha ?
I tryed to connect the Color to alpha node in every possible way that i can think of and still renders out

[Hirazi Blue]

Where you say "in the render it renders black", do you per chance mean in the render region? If so you probably using the "wrong" display mode for the render region. Setting it to "Alpha-blended RGB" should do the trick.
If you however mean "renders black" in a rendered image file, make sure the file format you use for your renders supports alpha channels ("PNG" for instance). And viewing the image correctly will depend a lot on the kind of image viewer you're using (some don't handle alpha channels all that well).


PS Maybe you could show us the resulting render also...

[pimeto]

Yes harazi, it render black in the PNG with alpha. Here is a render
Can you tell me how to set it so it renders alpha in the texture ?

Ah maaan, im so desperate right now that i started learning some basic ICE to render those engine boost effects for this ship, that will end up being used in 200x200px

[Hirazi Blue]

Sorry, I should have asked this yesterday also (it was late & I am feeling slightly ill...):
could you perhaps also show a screenshot of your render tree (edit: and perhaps the texture you're using)?
;;)

PS and/or maybe add a (partial) scene file if you're able/willing to share (parts of) it?

[julius]

I haven't the answer this time...Didn't succeed to drive the color to alpha with a texture.

Any idea ?

[pimeto]

I didnt succeed either. I have another problem now, that i just don't know where it comes from ?!

I render two passes, one for the head, one for the tail of this thing and the tail has animation to it. So when i look at the frames i have this like tiny little outline that occurs between the two passes.
I thought that i might've hit the smooth on some objects but this is not the case ?!
Anyone has any idea ?

You need to place them one over another in PS to see the outline spacing. I dont have motion blur enabled. Anyone has idea ?