Corona Renderer Forum

Corona Renderer for Cinema 4D => [C4D] General Discussion => Topic started by: caspian on 2018-08-27, 09:55:33

Title: Condensation - the hero sweat shot
Post by: caspian on 2018-08-27, 09:55:33
I'm relatively new to Corona and doing my best to work out how to do things differently (and why) to just bing in C4D. One thing I was trying to achieve on the weekend is replicate the condensation on a surface. In C4D I do it the way 3D Fluff taught me: using a number of noise shaders in the Normal and Displacement channels of the material. Corona materials don't have Normals, but it can be achieved in C4D with the Bump instead. Does anything have any bright ideas how this can be built with Corona? My attempt to replicate it didn't show up one the interactive renderer even using a corona water texture. Any help gratefully received. Thanks
Title: Re: Condensation - the hero sweat shot
Post by: beanzvision on 2018-08-27, 12:27:50
Hi,

You can easily add a normal shader found in the Corona shaders. Then you can link up your normal and bump maps. ;)
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=21556.0;attach=89917;image)
Title: Re: Condensation - the hero sweat shot
Post by: caspian on 2018-08-27, 12:30:54
Thank you! I haven't explored the material node system yet. I guess I ought to roll up my sleeves and give it a go. 
Title: Re: Condensation - the hero sweat shot
Post by: houska on 2018-08-27, 12:55:54
This is doable even without nodes. Nodes only give Ben a better way to show it
Title: Re: Condensation - the hero sweat shot
Post by: beanzvision on 2018-08-27, 12:56:42
You can also add it the usual way you would any other shader, so the don't think this is just limited to the node editor. ;)
Title: Re: Condensation - the hero sweat shot
Post by: caspian on 2018-08-28, 05:09:04
I'm not having much luck working this out. Should I be trying to create a layered material? I'm trying it this way for now but its looking pretty ropey. I'm using the same noise setup as my previous glass, so it should have a lot more droplets on the surface. I've also not worked out how to add a normal channel. I've found lots of tutorials out there for other apps but not many for corona materials +C4D. Am I going about this wrong?
Thanks!


-- update -- just watched a YT that confirms that material stacking is OK... but I still can't get a decent material out. :(
Title: Re: Condensation - the hero sweat shot
Post by: ficdogg on 2018-08-28, 10:32:03
To me, it looks like the projection or UVs on that shader ball you're using are stretched.
Anyways you add a corona normal shader to the bump slot, and then in that shader you have a slot for a normal map and an additional bump map if you need it.

PS
Poliigon has some nice water droplet textures if you want to go that route.
https://www.poliigon.com/search?category=surface%20imperfections
Title: Re: Condensation - the hero sweat shot
Post by: caspian on 2018-08-28, 23:37:35
Thanks for the tips – now I see where the normal is hiding! Ha. I'll have another go this afternoon. And thanks for the Link to those textures.
Cheers
Title: Re: Condensation - the hero sweat shot
Post by: caspian on 2018-08-29, 12:32:10
Forgive my basic knowledge of how Coronal handles materials but I must be missing something very obvious.
With a simple scene and a coloured cylinder, adding the water texture seems to be removing the coloured material below rather than adding to it.
My file is here if you want to see what I have done in more detail
https://www.dropbox.com/sh/u972nan919lqvw2/AAAfTA0ttjXtZFYCZeHgUzFVa?dl=0

Many thanks
Caspian
Title: Re: Condensation - the hero sweat shot
Post by: Redeemer on 2018-08-29, 12:47:17
This problem isn't really related on how Corona handles materials. The cylinder simply uses the material that is on top of the stack, so in this case the water material you've made. If you use an alpha mask which cuts out all individual drops and enable  'mix textures' it should work. You could also use a layered material for doing this, to keep things more simple. This workflow is more or less the same in Vray for C4d
Title: Re: Condensation - the hero sweat shot
Post by: caspian on 2018-08-29, 13:05:37
Thanks for the advice but neither of those tips produces what i was hoping for. I added an alpha…
Left: layered material | Right: stacked but with alpha.
I mush be missing something so obvious. I realise that this is still in beta and there are no official documents. I just wish I knew how to solve it.
The native c4d stacking allows materials to interact, which was why I (wrongly) assumed it would be similar.
Title: Re: Condensation - the hero sweat shot
Post by: beanzvision on 2018-08-29, 14:01:08
Thanks for the advice but neither of those tips produces what i was hoping for. I added an alpha…
Left: layered material | Right: stacked but with alpha.
I mush be missing something so obvious. I realise that this is still in beta and there are no official documents. I just wish I knew how to solve it.
The native c4d stacking allows materials to interact, which was why I (wrongly) assumed it would be similar.
Personally, I wouldn't attempt this with layered materials. I would rather use MoGraph (or another scatter plugin) to distribute the drops. Another method you could try is to create a clone of the bottle etc, One would have the glass material and the other would have the condensation on it. Trying to layer displacement can be problematic. Displacement is read from the first mat on the object, and placing it at the end will have no effect.

Mograph:
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=21556.0;attach=90045;image)

Duplicated mesh:
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=21556.0;attach=90047;image)
Title: Re: Condensation - the hero sweat shot
Post by: Redeemer on 2018-08-29, 15:00:14
Scattering droplets will have a different feel as the sweaty condensation type Caspian is after. I've only did this on glass where I simply put a condensation normals map in the bump slot of the material that I've used on outside of the bottle. I've tried to make a copy of the outside mesh of the bottle and have a separate water material with a normal map for the condensation and alpha for transparancy but that gave a lot of artefacts. Deadlines were quite close, so I had to fake it till I made it :)

It would be a lot better to have the condensation and glass separate though, so I'm curious in this solution too..

Title: Re: Condensation - the hero sweat shot
Post by: ozwald on 2018-08-29, 17:26:03
I also agree that Mograph achieves more realism.
Here is a sample I made with drops of water and ice
Title: Re: Condensation - the hero sweat shot
Post by: caspian on 2018-08-30, 04:30:41
Scattering droplets will have a different feel as the sweaty condensation type Caspian is after. I've only did this on glass where I simply put a condensation normals map in the bump slot of the material that I've used on outside of the bottle. I've tried to make a copy of the outside mesh of the bottle and have a separate water material with a normal map for the condensation and alpha for transparancy but that gave a lot of artefacts. Deadlines were quite close, so I had to fake it till I made it :)

It would be a lot better to have the condensation and glass separate though, so I'm curious in this solution too..



Redeemer, am I understanding right that in your render I'm looking at bumpy glass/label, and not water on the glass? The reflections don't seem right if it was if it was water.

Almost all of the Mograph tuts I've seen (like the popular GSG one) using scatters, randoms and falloffs make it look as if the droplets have been sprayed/stuck on and not the more convincing water effects I was achieving in my example at the top of the post using Physical Render (as if a bottle was taken out of the fridge and had a little time to warm up). I'm going to keep experimenting, but bare in mind I'm probably the least experienced person in this thread  :)

Thanks for all your advice so far.

---UPDATE -- I might have to invest in something like Spritz if I can't solve it before I go mad.
Title: Re: Condensation - the hero sweat shot
Post by: Redeemer on 2018-08-30, 09:33:18
Scattering droplets will have a different feel as the sweaty condensation type Caspian is after. I've only did this on glass where I simply put a condensation normals map in the bump slot of the material that I've used on outside of the bottle. I've tried to make a copy of the outside mesh of the bottle and have a separate water material with a normal map for the condensation and alpha for transparancy but that gave a lot of artefacts. Deadlines were quite close, so I had to fake it till I made it :)

It would be a lot better to have the condensation and glass separate though, so I'm curious in this solution too..



Redeemer, am I understanding right that in your render I'm looking at bumpy glass/label, and not water on the glass? The reflections don't seem right if it was if it was water.

Yes. I didn't had the time to figure out why it didn't work with a double mesh for the outside (one for the glass, one for the condensation). I will make a simple setup for testing that, if we don't succeed maybe some of the Corona guru's here can help us with that.

Personally I'm not too keen on that Spritz thing, it looks too fake imho.