Chaos Corona Forum
Chaos Corona for Cinema 4D => [C4D] General Discussion => Topic started by: nicuv on 2020-05-19, 12:01:25
-
Hello world, I'm back with a new question about lights in Corona Render. I have to do a simulation for a glass of yogurt and I would like to get some effects as marked in point 2 of the attached image.
Whatever setting you use in light, these are scattered throughout the object and not over a specific area of the object, as I wish.
He tried to make white planes that were reflected in the object but they are canceled by the scattering light.
Thanks a lot for the help
-
Hi there, Here's a rough scene that might help?
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=29485.0;attach=126762;image)
-
Wawww, thank you, I was putting the plan right and it is not reflected on the cone, thanks again.
However, isn't there a possibility in the light settings not to be scattered?
-
However, isn't there a possibility in the light settings not to be scattered?
See, if directionality is the thing you're looking for.
More on: https://help.c4d.corona-renderer.com/support/solutions/articles/12000023597-what-kind-of-lights-are-there- (https://help.c4d.corona-renderer.com/support/solutions/articles/12000023597-what-kind-of-lights-are-there-)
-
Yes, that's what I'm looking for, thank you all for your help
-
Hi again, is it possible to set a light in the Corona not to cast a shadow?
-
No, since Corona Lights are physically realistic, they always cast shadows (just like real lights ;) ). You can set objects not to cast shadows in their properties though. Or uses non-Corona lights that may have that ability (but which will have their own unique drawbacks of course).
-
I come back again, I added the texture to my objects, and I have a problem.
At the bottom there is a glow, at the intersection of the scene and the object, and I don't know why this happens.
The scene has a white material without reflection and the object has a white bottom edge with reflection.
-
That looks like a strong diffuse bounce to me. Make sure that white material on the cup thingy has a proper diffuse value (=~180 for white plastic) as it seems to be reflecting a lot. You can always dim it a bit too by making it even darker.
-
I also reduced the reflection of the object, it looks the same
-
Sorry for the double post, I came back with a bigger picture, and with the result of unchecking the reflection. Practically nothing has changed. Only if the object is a color other than white does that glow disappear. Does anything need to be changed in the general Corona rendering settings?
-
Hm hm, can you try lowering the diffuse level in the diffuse channel? Lower it to about 50%. Looks any better?
-
It is better that my object becomes too negative! :)
-
If I had to guess I'd say that your bitmap has an RGB 255 255 255 value on its white parts hence it is bouncing back a shit ton of light once your scene lighting hits it.
By lowering the level amount you've kind of clamped the color values in your bitmap to about half of what they were (probably around 127 if the level parameter works linearly) so basically you've made the entire bitmap darker.
That seems to have worked great for your whites but obviously it'll clamp the blue colors as well. So to work around that reset the level to 100%, open up your image editing software and clamp those white parts to a value of 180 (So thats 180 180 180 in RGB terms). That will fix the whites and keep the other parts the same :)
Still, you've got to remember that Corona (or any other modern pathtracer basically) doesn't work well with absolute bonkers values like white being 255 255 255. Not even snow is that white. White walls for example are typically around 170-200 tops. As far as other colors go, similar rules apply although for those I suggest you find a pleasant RGB value and then just lower the HSV value down a little.
Hope that helps!
-
Thank you for the help!
I tried to replace white with gray, and the result is better but not ok, the bottom of the object has a glow of the same color, why is this happening?
-
I'm personally mostly freaked out by the blueish glow that is around there - the grey / neutral seems in line with what I'd expect. Have you checked how strong you blue color is in that bitmap?
Also, if you could post an image with the whole scene (blur the client branding tho) and the light set up I think we'd have a better idea of what might be going on :)
-
That's what the scene looks like
-
Hmmmmm... I don't know, to me it looks like that blue in the texture might be too strong and it just color bleeds off to the floor. Seems natural to me. If you tone down the levels to 50% again, does the floor bounce look less blue?
-
The floor is not a problem, the problem in my scene is that glow that seems to come out from under the glasses, they seem to be lit on the bottom :), that's what I want to solve
-
If there is coming light from the bottom, the try to give the floor some thickness and see if that helps. Light leaks from objects without thickness is a known issue.
-
Thank you, nothing changes, still the bottom of the glass seems to be reflected in the floor, the material on the floor does not have the reflection activated. Even if the white in the glass material, let's say it's too hard, shouldn't do that, ugly :)
-
Thank you, nothing changes, still the bottom of the glass seems to be reflected in the floor, the material on the floor does not have the reflection activated. Even if the white in the glass material, let's say it's too hard, shouldn't do that, ugly :)
You can always upload it to our private uploader and we can take a look? ;)
https://corona-renderer.com/upload
-
Thanks a lot beanz, I just sent the scene, I'm waiting for an answer, I'm really curious what the solution is
-
Thanks a lot beanz, I just sent the scene, I'm waiting for an answer, I'm really curious what the solution is
Thanks for the file. I have made some changes and have sent the scene back via wetransfer. I deleted the floor and replaced it, I changed the material as is was too bright. This kind of colour bleed seems normal to me but I believe it has been reduced somewhat.
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=29485.0;attach=127140;image)
-
Thanks Beanz :). It still has a little glow :))))
-
Thanks Beanz :). It still has a little glow :))))
In the Advance tab > under Visibility of the material disable/ uncheck Visible by GI
... or get on down with the Rayswitcher (https://coronarenderer.freshdesk.com/support/solutions/articles/5000529341-corona-ray-switch-material-and-map)
or as they always say - fix it in post ;)
-
The solution here is to use the rayswitch material to override the material's GI, as Burnin explained.