Premultiply Without Halo?

[Anonymous]

Received CG elements from client rendered over white with embedded alpha. New to smoke, normally I would bring this into After Effects and set to premultiply and choose white as the background color. The result is a shadow with no halo when comped over black (or any other color). Trying to get the same result in Smoke. Using a blend and comp node in the modular keyer gets me closer, but I still have a gray halo around the shadow. Obviously I could render it out of After Effects and bring it into Smoke, but it seems like I shouldn't have to do that.

Any suggestions?

[Anonymous]

Seems like a negative node after the alpha would do the same thing as 1-alpha using a Logic Op to subtract.

I think John was emphasizing the math involved.

And please,  can we log this as a feature request as mentioned earlier in the thread. Receiving graphics premultiplied on white happens all too often, and confuses many who dont know how to deal with it.  Then they end up shrinking the matte or doing something else which compromises the intended look of the graphic.

[nadja.greisdorfer]

Is there a fix for that in Smoke 2017?

having the same problem with white background and can't figure out a work around.

thanks

[Anonymous]

Use Matchbox "Premultiply on Black".


Stephen Beecher
Flame Artist, Creative Services, The Bridge
stephen.beecher@disney.com
818-569-4849
[Disney Logo]

[nadja.greisdorfer]

Thank you Stephen!

solved my problem perfectly