i have 2 objects, a and b, with a color parm exported to an image plane. a is one color and b is another. how can i have b be a phantom object for all planes except for this colored image plane? i am trying to build masks into the shaders i am already using for the objects, but i need the mask to still show up when an object is phantom.

Hi,
The standard workflow is to create a set of Matte Channels in your surface shader. Using a simple colour parameter , then export . I use 3 of these in my shaders which I set to have a default of black. Thus allowing the user to pick either R, G or B.
You can render your object B as phantom but you still get the export plane. with a colour matte channel. There is an example of the work flow on my website.

Rob

thanks rob, that is how i am doing it, but cannot get the phantom object's export to show up. i just looked at the file on your site, and it also does not show up if switched to phantom. is there a setting for this or a way to tell mantra to still export the variable even though an object is phantom?

this is the page where i grabbed your file http://www.circusmonkey.com.au/circusmonkey/Shops.html [circusmonkey.com.au]

Ok . why do you want a matte for an object thats Phantom in the render ? Its not like the matte will be of any use . Instead of phantom just render the entire shot and use the matte on comp. Feel free to explain what it is your trying to render and why you need phantom.

Rob

i have multiple tiered pools of water, separated by a tree type thing that is holding each pool. i am rendering the pools of water in houdini which will then be comped with the tree from nuke. the tree needs to be phantom so that it shows up in reflections and refractions but the water is not masked by it. each pass is being re rendered by a script that smears the colors of the renders in 3d space with the passes from maya, so things dont line up exactly clean.
i could render out my passes how they are, and then render a separate mask pass with the tree unphantomed, but i really was hoping to have the masks just be extra planes of the same exrs. the main reason was so i wouldnt have to load the heavy fluid geo in twice, but i can just daisy chain rops to solve this. im guessing i cant have the exports show up while an object is phantom? its not necessary, but would make things much cleaner in our pipeline.

zdimaria
be comped with the tree from nuke. the tree needs to be phantom so that it shows up in reflections and refractions but the water is not masked by it.

Well if there's an element in Nuke your using surely that has a matte ? or Just make a new take and render that element on its own.

the main reason was so i wouldnt have to load the heavy fluid geo in twice,

Not sure it would be an issue if your making mattes. I write all my fluid stuff to disk and read in with no issues at all. its extremely fast.

rob

yes, because the maya element is partially occluded by the water and partially occludes the water i still need the matte. i will have to render the masks as their own pass i guess.

thanks for your time rob