Vegetation test + several more questions

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Hello everyone
I'm almost finished with the modeling part of my latest personal project, and it' time to finally use Corona for the first time :) (in a meaningful way)

I've set up this scene to test materials for vegetation and lightning.

Question 1

For materials i basically (and shamelessly) copied Adanmqs technique from this thread
https://forum.corona-renderer.com/index.php/topic,4867.0.html

But i need more eyes and constructive criticism on how to make my materials better (they are still cartoony). Part of the issue is that i need a walnut tree, and these trees look yellowish and diseased even in the middle of summer. So i created an oak tree to have as a reference (whit which i'm also not completely satisfied). In images bellow oaks are on the left, walnuts on the right.
Another thing i wanted to test are different sky models. Here they are:

http://i.imgur.com/OrWfXrg.jpg

http://i.imgur.com/Q8l7E7W.jpg


Here is the material for walnut leaves:
https://i.imgur.com/CQCxE1F.jpg

And here is the oak one, same thing slightly different settings:
https://i.imgur.com/UaJmRDt.jpg


Ideas? Suggestions?

Question 2 - Grass

Grass material:
https://i.imgur.com/B6FuxTv.jpg

Clover material:
https://i.imgur.com/stJAmq1.jpg


As you can see these are pretty much the same thing as the leaves, but for some reason, they behave quite differently with IBL lightning:
https://i.imgur.com/rpLhesB.jpg


I've set them up with Coronas Sun&Sky, and was surprised when i tested IBL. Lightning is done with pure IBL, using this HDRI
http://www.cg-source.com/details_hdrisky.php?id=0086-03&pricat=sky
Used sample version, much lower resolution but with all of the EV range.
Ideas? Suggestions? What is going on with that grass and clovers?


Question 3 - Background override

Background override image is just a gray mess, easily fixed by boosting it output. I always add background in post so this isn't really and issue for me :D I was just wondering if i'm doing something wrong, or missing some check box somewhere?
https://i.imgur.com/mqBXsNt.jpg


Question 4 - Environment fog

I've done my share of exploring this forum, and as far as i can tell what i want can't be done. Again, just to make sure i'm not missing something.
When Corona Volumetric material is added to geometry, it works, but it also affects background. Bad for post (completely easily solved with alpha channel).
This is what i'm getting:
https://i.imgur.com/VHO5b0E.jpg


I know that what i want (separate pass with just the fog for adding in post) is just an inverted z-depth, and that works fine. Like i said, just to make sure i'm not missing something.


Well, this is already to long of a thread. Tomorrow i'm away on a trip (if someone answers, i'm not being ungrateful :) ), but looking forward to any help and advice you fine coronauts can give me.
Thanks in advance!

[Ludvik Koutny]

Embedding your images directly into your post instead of just linking them will make your post appear a LOT more interesting ;)

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Embedding your images directly into your post instead of just linking them will make your post appear a LOT more interesting ;)

Fixed :)
I use thumbnail zoom plus ad on which shows images on hover, and always forget to do this :D

EDIT:
Damn, now half of the image is not shown :/ Luckily i've left links also.
EDIT 2:
Well, if i hide my All-In-One sidebar, than whole image is shown :D Don't mind me, it's late, i'm tired. Good night all...

[maru]

damn, firefox crashed, writing the whole thing for the second time -_-

Here are some reasons why your trees don't look so good:
-ugly models - your trees have flat leaves and leaf clusters while in real life they are all curvy and wavy and wrinkled
-leaves look huge (but maybe it is like this for this kind of tree?)
-wrong map in translucency slot - for translucency you should use the same map as for diffuse, or you can slightly modify its colour using color correction
-white borders around leaves - it's because your diffuse map is a green leaf on a white background while it should be a green leaf on green background
-for leaf reflectivity, use some glossiness!
-use darker diffuse map or decrease diffuse level
-basically, you can try googling some real-life reference and comparing it with your material setup

[Adanmq]

Hi.

I think the main problem is the flat mesh of the leaves as Maru pointed. You need curved mesh in order to catch highlights. The trees itself looks weird, i don´t know if the problem is the scale or the leaves orientation. I prefer to use 2 different materials, one similar to the one you have for mid/far range images, where the most important part it´s translucency and highlight, so you can exagerate these parameters. And one for the close-Up renders, where you need more complex material and more detailed geometry also.

Try to improve the model itself and you will get better trees. If you have some references of the Walnut tree you are trying to achieve maybe i can give it a try in GrowFx.

[Adanmq]

I make a quick walnut in GrowFX using a random image i found on google. Its just a fast attempt and i´m not sure if the tree "anatomy" is correct (leaves are way to big) but i want to share it whit you so you can experiment. I can´t share the textures because they are not mine (very simple ones, nothing especial), you can download some good ones from Xoio Air for example or find the real walnut ones, xD. Also i try to make you a very simple material that works "ok" for most of the shoots. As you can see in the attach Close-Ups will need better leaves and material.

You can create grass material using the same principles. Curved geometry and reflective/translucent materials.

Here is the Walnut tree (i can´t make it smaller in order to attach it to the post sorry):
http://we.tl/csHkfHXjPS

PD: Excuse mi English.

[CiroC]

This is a very interesting topic since I am also working with loads of plants.

From my experience so far, the 3D model is perhaps 90% of what makes a tree realistic. What models are you using?

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-ugly models - your trees have flat leaves and leaf clusters while in real life they are all curvy and wavy and wrinkled

Premade Xfrog trees, not much i can do about that, besides, you know, learn how to use xfrog and create them on my own :D

-leaves look huge (but maybe it is like this for this kind of tree?)

On purpose, they do have huge leaves.

-wrong map in translucency slot - for translucency you should use the same map as for diffuse, or you can slightly modify its colour using color correction

But, it's the same setup as Adanmqs vegetations, which looks great. Am i missing something?

-white borders around leaves - it's because your diffuse map is a green leaf on a white background while it should be a green leaf on green background

Will fix, don't know how i missed that, i even fixed it on clover material but it completely slipped my mind for the trees.

-for leaf reflectivity, use some glossiness!

I actually thought that for glossiness same thing as in mental ray applies, once you plug bitmap in glossiness slot, spinner no longer does anything and everything is controlled by bitmaps output. I just tested it and it's not so in corona, those two work together. Will test this.

-use darker diffuse map or decrease diffuse level

Then i'll loose that yellowish look that walnuts have. Oh well, i guess loosing some of the real life tree look is worth for a nicer render :)

I make a quick walnut in GrowFX using a random image i found on google.

Thank you very much!
I will use this for further testing, until i figure out how to use xfrog. Or, since this is just my personal project i'll use your model :D Laubwerk also has some free ones...

You can create grass material using the same principles. Curved geometry and reflective/translucent materials.

Grass is curved geometry with reflective/translucent material, i don't know why it behaves so differently in different lightning solutions.

From my experience so far, the 3D model is perhaps 90% of what makes a tree realistic. What models are you using?

Xfrogs premade models, i export them as 3ds.


Thank you all! I will start another batch of tests and get back with the results.

[romullus]

As Adanmq was so generous to share his beautiful tree, i want to contribute either. As it hapens, there's two gorgeous walnut trees growing in my backyard, so i thought i can make some cool textures out of it's leaves.

These are english walnuts, i believe.

[Adanmq]

Awesome Leaves. I´m living in Caribean Coast right now and its really dificult to find non-tropical trees arround here. Thx a lot!!.

[maru]

-wrong map in translucency slot - for translucency you should use the same map as for diffuse, or you can slightly modify its colour using color correction

But, it's the same setup as Adanmqs vegetations, which looks great. Am i missing something?

Compare these two:



Definitely not the same. :)

-for leaf reflectivity, use some glossiness!

I actually thought that for glossiness same thing as in mental ray applies, once you plug bitmap in glossiness slot, spinner no longer does anything and everything is controlled by bitmaps output. I just tested it and it's not so in corona, those two work together. Will test this.

Ok, my bad, didn't notice your bitmap in glossiness slot. It works like you described it, except the glossiness spinner determines maximum allowed glossiness for the bitmap (or at least it should).

[romullus]

Ok, my bad, didn't notice your bitmap in glossiness slot. It works like you described it, except the glossiness spinner determines maximum allowed glossiness for the bitmap (or at least it should).

No, it doesn't. This spinner does nothing, as soon as you plug map into glossiness slot.

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Compare these two:
Definitely not the same. :)

Yea, i figured that out last night. I was again under the wrong impression how stuff works in Corona, i thought that translucency bitmap is a mask for selected color, but it actually affects translucency color.

No, it doesn't. This spinner does nothing, as soon as you plug map into glossiness slot.

It definitely does something! Try it, even with the glossiness map plugged in spinner still has an effect.

As Adanmq was so generous to share his beautiful tree, i want to contribute either. As it hapens, there's two gorgeous walnut trees growing in my backyard, so i thought i can make some cool textures out of it's leaves.

There are two walnuts tree in my backyard also! But they are no longer gorgeous, i think i picked the last green leaf :D
Here they are. If needed i can share raw photos as well, if someone with better photoshop skills wants to take a shot at them.

[romullus]

No, it doesn't. This spinner does nothing, as soon as you plug map into glossiness slot.

It definitely does something! Try it, even with the glossiness map plugged in spinner still has an effect.

Are you sure you're not mistaking it with reflection map?

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Are you sure you're not mistaking it with reflection map?

I never use reflection maps. But, you're right. I tested this last night, but obviously i've done something wrong. I just retested and indeed it's the same as with mental ray. Once glossiness bitmap is plugged in, spinner does nothing.