Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] I need help! => Topic started by: wardy_mk on 2023-04-12, 19:14:57

Title: Total novice here. Need help with transparency etc
Post by: wardy_mk on 2023-04-12, 19:14:57
Hello. I'm very new to Corona but not to Cinema 4D. I'm just starting with learning this and it seems to be going pretty well. I have three queries really, if you could be kind enough to answer them.

Firstly, why does my viewport in cinema show any transparent or translucent materials as solid black.
 
Secondly, any material that has an alpha channel/transparency elements (such as logos etc) show the area of the image that's transparent as a solid colour. Why is this?  Everything renders out okay, just the preview in the working area looks awful. I can't seem to find anything to 'enable better preview'.

Lastly, there don't seem to be many options for lights and stuff. Targets, shapes, etc. Am I missing something? I'm assuming they've very in-depth but I don't know what to do or where to look...

Thanks in advance
Andy
Title: Re: Total novice here. Need help with transparency etc
Post by: Beanzvision on 2023-04-13, 09:32:24
Hi,

1 & 2 is expected behavior. You could always use a standard C4D material whilst prepping your scene and then switch it come render time.
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39831.0;attach=181978;image)

3. Targets for lights work the same way as they do for standard C4D lights. You need to add a target tag to the light and then assign your target. As for shapes etc, what exactly do you mean?
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39831.0;attach=181980;image)
Title: Re: Total novice here. Need help with transparency etc
Post by: BigAl3D on 2023-04-13, 15:54:21
Sounds like he may be referring to gobos perhaps? Corona light can be any of six shapes, plus you can add a Corona Light material to ANY object.
Title: Re: Total novice here. Need help with transparency etc
Post by: wardy_mk on 2023-04-13, 18:14:25
No, that last fella sorted it for me. Thanks. Was mainly concerned with targets as I usually just grab a 'target' spotlight.

How would you achieve, for example, a strip light in Corona? Like you would use under a shelf in a store?
Title: Re: Total novice here. Need help with transparency etc
Post by: TomG on 2023-04-13, 19:06:14
Corona Light, rectangle, scale it in one axis only.
Title: Re: Total novice here. Need help with transparency etc
Post by: Beanzvision on 2023-04-18, 09:16:21
Yep, as mentioned by Tom, this should be the way to go ;)

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39831.0;attach=182108;image)
Title: Re: Total novice here. Need help with transparency etc
Post by: wardy_mk on 2023-04-18, 12:17:46
THANK YOU!
Do I need to 'fake it' if I want to see the light itself? What about visible light emitting from the light? See below...
Title: Re: Total novice here. Need help with transparency etc
Post by: Beanzvision on 2023-04-18, 12:33:39
Hi, I'm not entirely sure what you mean, the example is rather small. But there shouldn't be a need to fake anything as Corona is a physically accurate renderer. Lights are visible by default. I hope that helps! :)

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39831.0;attach=182131;image)
Title: Re: Total novice here. Need help with transparency etc
Post by: wardy_mk on 2023-04-18, 13:16:24
Thank you!
Title: Re: Total novice here. Need help with transparency etc
Post by: wardy_mk on 2023-04-18, 13:19:56
Hello! I have another strange question! Sorry!
I am modelling a car showroom. It has glass on all four sides. So I've created one large glass panel on each side and dropped a corona texture onto them. When I do that, a strange bubble appears in the VFB!
Can anyone explain this? What's going on?
Title: Re: Total novice here. Need help with transparency etc
Post by: Beanzvision on 2023-04-18, 13:23:17
Hi there, can you share the scene with us? It looks like a sphere to me.
Title: Re: Total novice here. Need help with transparency etc
Post by: TomG on 2023-04-18, 13:25:51
I am not clear about "dropped a Corona texture onto them" - glass shouldn't have any texture applied surely? Just a glass material.

Also not clear on what is meant by "bubble" - do you mean the sphere in the center of the scene? The material applied to the glass planes wouldn't cause that. Do you have an environment for the scene in "dome" mode? If so it may be too small and the camera is outside it and you are seeing it as an object inside the scene rather than the scene inside of it :)
Title: Re: Total novice here. Need help with transparency etc
Post by: Beanzvision on 2023-04-18, 13:32:25
I am not clear about "dropped a Corona texture onto them" - glass shouldn't have any texture applied surely? Just a glass material.

Also not clear on what is meant by "bubble" - do you mean the sphere in the center of the scene? The material applied to the glass planes wouldn't cause that. Do you have an environment for the scene in "dome" mode? If so it may be too small and the camera is outside it and you are seeing it as an object inside the scene rather than the scene inside of it :)
Yep, that's exactly what it looks like now you've mentioned it :)

@wardy, if you increase the size or switch the projection to ''spherical'', you should be good to go. I don't see a need here to use dome mapping.

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39831.0;attach=182137;image)

Title: Re: Total novice here. Need help with transparency etc
Post by: wardy_mk on 2023-04-18, 13:38:42
Hello.
Basically, I have the four large panels of the box. I took the glass material from the Cosmos browser and I dropped it onto the group holding all the glass. Was UVW mapping as standard. Tried to amend it to spherical and this mysterious dome is still there!

I can't share the file as I've signed a NDA etc.
It only appears when I look 'through' the glass. If I look down at the model it's not there...>!

Here's a couple more pics. Please help :)
Title: Re: Total novice here. Need help with transparency etc
Post by: Beanzvision on 2023-04-18, 13:49:30
Can you strip back the scene to a point where it still happens and share it with us? Also, can you share a screenshot of the Corona sky lighting settings? What if there is no glass at all? Can you also show the glass material setup?
Title: Re: Total novice here. Need help with transparency etc
Post by: wardy_mk on 2023-04-18, 13:59:03
Oh my gawd, I found it!
Sorry, total schoolboy error. there was something in there from a 'previous' scene.
Why it only appears when the glass is there is another subject but I THINK I've solved the mystery. Thanks everyone. :)
Title: Re: Total novice here. Need help with transparency etc
Post by: Beanzvision on 2023-04-18, 14:08:01
And what was it?
Title: Re: Total novice here. Need help with transparency etc
Post by: wardy_mk on 2023-04-18, 14:27:27
I'm embarrassed to say, but on 'normal' projects I don't use Corona. I have a reflective sphere in which my items all sit - and I have a luminance material applied so that it appears on reflections. There's a tag on it to not be visible to the camera though. Somehow it's becoming visible when Corona comes into play. Usually I'm just designing retail display units - not whole car showrooms... When I started the scene - although I'd switched it off it still came into play.

No probs!

Have a minor material issue now haha. I'll leave you alone for a bit though!
Title: Re: Total novice here. Need help with transparency etc
Post by: Beanzvision on 2023-04-18, 16:33:55
Hi, no need to leave us alone, we're here to help. What's your material issue? Fire away!
Title: Re: Total novice here. Need help with transparency etc
Post by: TomG on 2023-04-18, 16:52:57
Yep just delete everything and leave four panes of glass and send it in - if that still shows the sphere. That way no NDA breach since it's just four planes of glass :) Do you have any environment overrides on the glass, e.g. for refraction or reflection?