Render order question

[rurik]

I'm running into an interesting 2d/3d render order question...

I have a model imported as FBX. It comes in as parts, some of it the main architecture and some of it the LED strips I'm applying content to.
At first I had everything piped into the main Render TOP, and all was good.
But then I realized I needed to apply some effects to the LED geometry textures, so I broke those away into their own render TOP to be able to apply color correction TOPs to them. I then piped both render TOPS into an Over TOP and here my problem comes...the LED geometry is now rendering "on top" of the architecture, i.e not respecting its position in Z-space. I am still able to cull it properly, but a piece of geometry appearing on top of the LED is basically masked by it.

This seems like a typical 2d taking over 3d rendering order thing, and I wonder if there is any way around this?

Thanks
Alex

[keithlostracco]

Rather than using a second render top try using a renderpass top along with your rendertop. In the renderpass top choose the same camera and lights but only choose the led geometry. Then you can comp the two tops back together after processing. If the render pass doesn't mask out the led's you can make a copy of the other geometry and add a black shader to it. Then choose led and the black geo.

cheers
Keith

[rurik]

Great solution!
Thanks for that...
Only issue I can see is that the are where my LED and the building overlap, my compositing operations to the building (blur) affects the contour of the geometry as well, as it is being "cut out" of the LED...I feel like I would have the same problem if I used the black shader on a copy of the geo...
But this is definitely better than having it masked...

Thanks!