Author Topic: Render Object selection with reflections of object in scene  (Read 1207 times)

2021-10-20, 17:42:00

l.croxton

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Hi,

Sorry but I can't figure this one out and its driving me a little nuts!

I have a scene where I need to replace an objects shader (configurator) numerous times. Now the objects in question obviously reflect in other elements in within the scene and I want to be able to capture those reflections within the object render selection.

So as an example.

I have white room with mild reflective properties, enough to see a faint reflection of the orange ball that sits in the middle of the scene. I now want to make that orange ball black with blue stripes, I apply the new shader and want to render the ball. However the reflection within the roomset is still of the orange ball, so without needing to render the whole scene, I just select the ball and hit render. This then includes the reflections cast on the rest of the room, so in photoshop I can just drop the new layer in which is of the ball and its captured reflections and overlay it.

I'm trying to get away from relying on FStorm (having to work with some other visualisers which do not use this engine) which does this feature perfectly with its render object mask in the kernel settings and I have no doubt Corona can do this as well, I just can't for the life of me find out how. The best I have found is of the shadow catcher, but I can only assume this could work if I applied the that shadow Catcher material to the WHOLE scene and render it like that? which just seems like a huge pain to set up as for each element I need to render I would have to have a shadow catcher variant of the scene specifically for it.

Any advice on this?

If I am allowed I'll include the image which demonstrates exactly what I am after.

https://fstormrender.ru/wp-content/uploads/2017/05/RenderMaskM.jpg

Any help on this would be hugely appreciated.

2023-08-04, 22:34:00
Reply #1

arielsmarin

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2023-09-01, 16:16:47
Reply #2

maru

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Sorry, but I don't understand this request. Going back to the original example: a colored ball in a reflective room where you change the color of the ball. How exactly could we render those configurations without re-rendering the whole scene? Changing the color of the ball affects pretty much all the rest of the scene (reflections but also the overall global illumination bounces). So if we do not re-render the whole thing, then there is no way to capture all changes.
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2023-09-03, 04:28:02
Reply #3

arielsmarin

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the idea is not to render the whole scene, but only the object to be changed by the configurator, for example we have a panoramic kitchen configurator in which when we change the cabinet's tonality, the reflection that this cabinet produces can be captured with its transparency to be applied on top of the image as a photoshop layer, without the need to render the whole scene.

render a selected object, with its reflection in transparency for compositing, its possible in corona renderer?

Captura-de-tela-2023-09-02-232513" border="0

2023-09-04, 09:14:58
Reply #4

Aram Avetisyan

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Hi,

So basically you want to render/composite a single object but to have all the affecting things coming with the objects (teapot) into the scene. In such case, it is not a "masked" or part rendering but rather a full rendering with almost the rest of the scene (or the needed, predicated parts) as shadowcatcher material. There is no other way to filter one object and have all its depending reflections, lighting contribution etc. in the scene. You can as well use the reflection render element but you will need to mask things about to have only the teapot's effect.

So the solution in your case will be to assign (or model first if the objects are not present) shadowcatcher material(s) to the rest of the objects other than the teapot, and control their reflection parameters accordingly. Set Shadowcatcher alpha to Compositing and save out the render will alpha channel. Then you should achieve the same results as you attached.
Aram Avetisyan | chaos-corona.com
Chaos Corona Support Representative | contact us