Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: mikerogers74 on 2024-07-18, 09:59:35

Title: Compositing with backplate and masking
Post by: mikerogers74 on 2024-07-18, 09:59:35

Hi All,

I this video

 at the 14:23 minute mark the author shows how to partially obscure the 3d model using vray. I was wondering if there was a way to do something similar with Corona. I have seen people do it in post using masks photoshop but would prefer to do it in Max.

Thanks

Title: Re: Compositing with backplate and masking
Post by: Aram Avetisyan on 2024-07-18, 11:05:22

Hi,

I don't see anything done in the video (except VRay specifica things, e.g. tone mapping operators) which is not doable in Corona. Specifically having a separate environment for illumination, separate image for background/backplate, and a shadowcatcher. You can check this video made some long time ago, maybe you find it useful (the functionality is there and may even be improved, the UI might have changed too):

list=PLt4UrWcQaAX-k40KpVTt-EMorC_mOfieR

Title: Re: Compositing with backplate and masking
Post by: mikerogers74 on 2024-07-18, 13:47:49

Hi Aram,

Thanks for the reply. It's not the HDRI, backplate image etc which I have a problem with. Near the end of the video the author uses a vraymaterial with an opacity bitmap and enables the Matte option. Afaik Corona does not have a Matte option? Was wondering if there was a a way of doing this

Title: Re: Compositing with backplate and masking
Post by: Aram Avetisyan on 2024-07-19, 02:12:04

Yes, I think there should be a way to do it in Corona - either with the same object settings or through RaySwtch or shadowcatcher.

I generally don't see anything being done in the video which is not possible with Corona.
If you have a specific scene/case (screenshot or video will help) with exact thing to accomplish, I may help you further and more precisely.
If it is fine for you, you can share a scene so I can "fix" it directly in it.

Title: Re: Compositing with backplate and masking
Post by: romullus on 2024-07-19, 21:52:34

That should be easy - just create box, position it where the column that blocks the way is and apply the same shadow catcher material that you normally apply to the ground.

Title: Re: Compositing with backplate and masking
Post by: mikerogers74 on 2024-07-21, 04:42:21

Hi Aram,

So uploaded a scene to test with. Included in the zip file is a file called composite.png which is output from photoshop using the mask mask.png which would work in the vray workflow described above. If you want i can create a scene using vray soln for comparison.

Hi Romullus,

A box with shadow catcher works ok when the geometry is simple but if it's not something simple like a pillar (eg: plant) then this is a no go.

Thanks

Mike

Title: Re: Compositing with backplate and masking
Post by: romullus on 2024-07-21, 10:22:58

It's possible to do so with the painted mask too, albeit it's a bit hacky approach and for some reason requires additional cancellation of tone mapping, but it seems to be working. look at the attachment, i think it should be self explanatory.