Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Ceyes on 2017-01-06, 09:36:52

Title: Compositing Rendered Objects later in a Scene
Post by: Ceyes on 2017-01-06, 09:36:52

Hello,

i need to render out an animation of a tunnel/street. The first rendering is with cars an the second rendering should be the cars only. Then it could be composite in fusion later.
I am new to compositing. My goal is to save rendertime, if the ainmation of the cars would be changing, i am only rendering my cars new.

So here are my steps so far:
1. rendering out the scene without cars (in Elements for later compositing)
2. Rendering the cars only with "Render selected"
3. Layering in Fusion

When i use "Render selected" the cars and the alpha-Channel are good, but the shadows from the cars are not in there. Is there a way to get a pass with full materials and refelctions (like "Render selected") + Shadows of the selected Objects?


Thanks in advance

Mirko

Title: Re: Compositing Rendered Objects later in a Scene
Post by: romullus on 2017-01-06, 12:12:42

CoronaShadowCatcher material is your friend here. You could choose alpha mode for compositing, assign it to tunnel objects and render cars as normal, without render selected. Unfortunatelly, currently for compositing mode is broken and renders very noisy. And that makes it not very viable solution :[

Title: Re: Compositing Rendered Objects later in a Scene
Post by: Ceyes on 2017-01-06, 13:14:32

Hey romullus,

the problem with the shadowcatcher material is, that the cars are reflecting the tunnel materials. If i change the material of the tunnel, here to shadowcatcher, the cars are not reflecting anything. The only workaround here, is to use the rendered image of the tunnel as backgroundimage for the shadowcatcher. This would be fine for the time the cars are in the tunnel, but later in the animation the cars are outside where many tress, houses etc. are narrow to the street.  A solution line "render selected for compositing" would be realy nice. ;)

Title: Re: Compositing Rendered Objects later in a Scene
Post by: mraw on 2017-01-06, 13:26:18

if  SDW-catcher is noisy, you still might be able to use it if you can live with soft shadows. Blur(or denoise) it until noise vanishes and use the alpha of the cars as a mask/cut-out.
It might work in your scene, probably not, by I would give it a shot. Mblur is rendered or post?

You might want to use the SDW-catcher-material inside a rayswitch to preserve the reflections(No Max here... just a shot in the dark)

Title: Re: Compositing Rendered Objects later in a Scene
Post by: Ceyes on 2017-01-06, 13:42:13

Hey mraw,

Quote

You might want to use the SDW-catcher-material inside a rayswitch to preserve the reflections(No Max here... just a shot in the dark)

Yes, that was my first idea, but in the scene are a lot of materials to change, so this would al lot of work. But it can be the technical background for the "render selected for compositing-feature" ;) Hey Ondra ;)

Mblur is rendered, but if this would be the only problem i would add it in post.