Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: cjwidd on 2019-06-17, 10:47:52

Title: bottle of water
Post by: cjwidd on 2019-06-17, 10:47:52
Having a hard time getting a good read on glass and water materials, looking for any advice the forum can offer. Reference and test render attached.
*ground texture not to scale

EDIT: 'test2' attached

test.png =test render
DRC01087.JPG = photo reference
test2.png = test render
Title: Re: bottle of water
Post by: cjwidd on 2019-06-17, 22:07:33
Basically I am tinting the glass slight green and the water slight blue, but the problem seems to be in the glossiness of the glass surface and the glossiness of the water.

Decreasing the refraction glossiness of the water too much creates a gel-like appearance in terms of reflectivity, making the solution appear more solid than it should.

It would be nice to emulate the condensation that is blurring the surface of the glass, but I have yet to find a solution. Perhaps a glass map will do the trick?

I experimented with the velvet shader to imitate the effect, but to no avail.
Title: Re: bottle of water
Post by: cjwidd on 2019-06-19, 19:39:46
I spent some time researching techniques for rendering liquid / glass interface and it seems to be something that is avoided. There are plenty of pristine product renders of perfume, whiskey, vodka, etc. but few with actual surface detail, almost none with water, and I did not find any with soft condensation - not water droplets.

Title: Re: bottle of water
Post by: John.McWaters on 2019-06-19, 21:02:44
Can you upload your file?
Title: Re: bottle of water
Post by: cjwidd on 2019-06-19, 21:25:23
I can probably show a breakdown of the shader graph. Note: I am following the guidelines for liquid / glass rendering per Corona recommendations (https://coronarenderer.freshdesk.com/support/solutions/articles/5000515618-how-to-model-a-liquid-in-glass-with-corona-renderer-)

see attached 'breakdown_tex' for texture assignment
see attached 'breakdown' for node details
Title: Re: bottle of water
Post by: cjwidd on 2019-06-19, 22:30:15
updated render
Title: Re: bottle of water
Post by: sebastian___ on 2019-06-20, 09:36:02
That's a massive improvement. For example between the first render test.png and test2.png which looks almost like the photo reference.
Title: Re: bottle of water
Post by: cjwidd on 2019-06-20, 09:52:13
I am glad you liked the test renders, although I felt that they fell short of the photo reference (DRC01087.JPG). That being said, I do agree 'test2.png' is a more faithful representation than 'test.png'.
Title: Re: bottle of water
Post by: romullus on 2019-06-20, 11:00:00
Is there any reason why you're adding fallof on top of the fresnell in reflectiona and refraction?
Title: Re: bottle of water
Post by: cjwidd on 2019-06-20, 11:29:34
It helped punch the dark tones to define edges (boundaries) of the volume for both the water and glass bottle
Title: Re: bottle of water
Post by: romullus on 2019-06-20, 11:49:33
Thing is, that now you're getting physically incorrect reflections and refractions. That might explain why you're struggling to recreate photo reference.
Title: Re: bottle of water
Post by: cjwidd on 2019-06-20, 12:03:26
I have to say, I have dialed in just about every reasonable permutation of parameters to try and emulate the surface depicted in the reference image, it is just very complex.

Ignoring the fact that the texture set I created is not an accurate description of the reference in the first place, there are a number of factors that complicate the matter further. Primarily the fact that any bump or gloss offset will dramatically alter the translucency, creating something that looks more gel-like  than glass.

I am willing to acknowledge that the render does not portray a physically accurate surface, but I would contend that it is at least lifelike in some respects.
Title: Re: bottle of water
Post by: sprayer on 2019-06-20, 12:15:05
i think if you want soft condensation without droplet you also do not need it in bump slot as small details in bump gives more glossy look in reflection what may interfere to glossy map.
sharing scene will give to users for experiments ;)
Title: Re: bottle of water
Post by: mferster on 2019-06-20, 17:36:43
It might be that the model itself needs adjustment rather than the material at this point. What does a cross section of your model look like?
Title: Re: bottle of water
Post by: cjwidd on 2019-06-20, 18:26:25
Unfortunately I cannot share the project files at this time, but I have attached a cross-section of the model to offer some insight.

Title: Re: bottle of water
Post by: mferster on 2019-06-20, 21:22:14
hmmmm, you could try adding some subtle width variation of the inside glass faces and increasing the thickness near the bottom and the top a bit more. See if that makes it look closer.
Title: Re: bottle of water
Post by: cjwidd on 2019-06-20, 21:36:18
Yeah, deforming the inner faces with some noise might be a good idea. I did, however, apply a noise to the bump channel of the water body, which helps to create a similar effect.

Something I haven't tried is creating a car paint-like shader to create a layered effect, but I know that would increase the render times even more.