Nuke holdouts?

#1

Hey folks! Junior comp artist here :smiley:

I’m a little stuck with a project I’m working on, I have a snowy scene all layed out with clouds and snow layers on card3D nodes, and I have some base geometry from maya - however I can’t seem to get the snow and clouds behind the geometry when they should be?

I’m thinking I could possibly use the depth channel of the geometry somehow, but I’m not entirely sure.

A prime example of the situation is shown in the attached photos: I’ve got some buildings and I want the snow planes that should be behind them to actually render as being behind them, but how would I do that as I cant combine card3D and geo nodes into a scene?

Admittedly I’m just screening the snow over the rest of the comp when it’s all together, so ideally I’d need a solution that can holdout each individual card3D and delete the space where that card wouldn’t be seen behind the geometry - any ideas?

Any help would be greatly appreciated! Thanks! :stuck_out_tongue:

#2

Maybe it is a stupid suggestion but can’t you create
some copies of scene and scanline render with or
without a card and switch between them?

#3

if i understand you right: you render the snow seperate and screen/plus them back again?

then you need the house geo also in the scene with the snow cards and give them a “fill mat” material

#4

All sorted now! I solved it earlier and forgot to reply aha sorry.

I ended up converting all the card3Ds to cards and ran them through a scanline render attached to my camera. The geometry was linked in with a black material and then obviously the scanline render was screen’d back over the footage.

Here’s the setup:

And here’s the final look for a bit of self-promotion :cool:

Thanks guys! :smiley: