Combustion - masking operators

[timmatron]

Say I have a footage layer, and I apply a color correct operator to it. Is there a way to select a mask that will allow me to only use the color correct operator on the masked area? And then I would like to be able to do that several times to different parts of my base footage. Sort of how in Photoshop you can have a main layer with lots of adjustment layers & masks on top of it.

I know I could copy the layer a bunch of times and them do a 'set matte' for each channel I want to work on, but I'm worried that would lead to too many layers and too much memory usage.

Any suggestions?

[RErender]

Under selection operators you have a few choices, draw selection will allow you to make a selection just like drawing a mask. As long as the selection is set to "replace" it will ignore or work on top of the previous selections. If you are working with actual rendered alpha mattes then use the compound channel selection operator.

[timmatron]

Thanks, we will most likely be using the rendered alpha masks so I will give this a try soon. This is my first professional Vray animation, plus trying to learn Combustion at the same time so I am just trying to keep my head above water. So far Combustion is great, besides the random crashes. But I guess that comes with the territory when you are working with Autodesk/Discreet products.

[mike.edel]

if you render your mask to the color channel of a seperate image you need to add a compound alpha arithmetic op on top before using it in the compound channel selection op
this is because the compound channel selection op only offers red, green, blue or alpha as input
the compound alpha arithmetic operator takes the luminance of the mask and outputs it as alpha



structure would be sth. like this:

#Color Correct operator
#compound channel select operator (targeting the alpha of the mask image)
#source

i'd suggest working in flowchart mode for this - makes it easier to rewire the flow

mike

[timmatron]

Awesome, thanks Mike!

[panthon]

In case u are working with max rendered footage, don´t forget u can use the rpf format, which will allow u to select masks based on the 3d objects, without the hassle of manually adjust the mask every single frame. The object id channel rendered by vray is able to save all this time...

IN general terms, i would add to what´s been said that u can also paint your selections or masks using a paint operator. It can be useful sometimes (like chroma key clean-up), but i think it´s no rival to bezier splines masks.

[timmatron]

In case u are working with max rendered footage, don´t forget u can use the rpf format, which will allow u to select masks based on the 3d objects, without the hassle of manually adjust the mask every single frame. The object id channel rendered by vray is able to save all this time...

Ahh, one more thing to try. I will definitely look into that. Thanks for the tip.

[timmatron]

Question on rpf format...if you want to save an rpf, do you also have to select and turn on the Vray gbuffer layers that you want to include, like zdepth and object id? Or does the rpf save that information even if you don't actively render them in the gbuffer?

[panthon]

You must activate them in the vray colormapping/gbuffer section. If u plan to use object id, don´t forget to tick the coverage channel, u´ll get better masks.

[timmatron]

Thanks. My head has been spinning in circles since I started this animation project.

[panthon]

Combustion will make your head spin even more...Sometimes it can be quite confusing, even when u are an experienced user...But it´s so powerful that it´s worth the time u spend learning it indepth.

[timmatron]

Hey guys thanks for the help. I finally had a chance to try the compound arithmetic thing and got it to work. I don't think I would have though, if Mike hadn't shown me the schematic view.

Haven't figured out rpf's yet, but it's on my list.

Thanks again.