Need help with Leaves and Vray2SidedMtl

[Guest]

Hi,

can someone help me with tweaking and explaning the Vray2SidedMtl for my Leaves. (A Max 2017 / 2018-File with my textures is attached)

The only Tutorial i found was this one:
http://www.peterguthrie.net/blog/200...torial-leaves/
But this didn't helped me very well.

As a starting point I used a sample tree from Evermotion: (SAMPLE TREE)
AM176_017
https://evermotion.org/shop/show_pro...-vol-176/13518

What I can not understand is why I have to use a Map for the Translucent slot in the Front Material. If I disconnect this Map I get a grey Back Material. But why????


Just to understand that I am on the right track: (for the vray2sidedmtl)

When a light (the Sun) hit the leave, the leave will be transparent. But in shadow areas the leaves will show the front/back Material (depending if you look from top or bottom)

Perhaps some one give me some hints.

Thanks in advance

Carsten

[Midiaeffects]

I most likely would approach this material differently. Not that your setup is wrong, even because Peter is a great artist with lots of experience, but mixing Vray2Sided with VrayMtl using translucency inside doesn't make much sense to me. Also, as Vray2Sided is feeded with materials, this means it blends also reflection and other stuff, making things trickier than they need to be.

Although my nodetree may seem more complicated, it's actually much more logical as everything is properly separated. I use Vray2SidedMtl solely with diffuse textures on them, no translucency or reflection whatsoever in the VrayMtl inside. This makes 2 sided work predictably, then I use a VrayBlend to add a reflection on top of the translucent Vray2SidedMtl (for the coat, I make a VrayMtl with white reflection with no fresnel, and use a Fallof in Fresnel mode as a mask). So reflection is not dimmed or mixed in the 2Sided material. Then I use a VrayBumpMtl to add bump to everything so there's no need to instance maps between front, back and reflection layers. And the last step is the cutout, which similarly to bump, applies to everything underneath so no need to instance maps everywhere. I do that with a trick I've learned from Vlado sometime ago, with another VrayBlend with no base material (so it becomes non renderable), and my material is the coat, the mask of the coat is the cutout.

As I said, seems complex, but it's actually more logical and simple to work with IMO.

But all of this would be waaaay simpler if we had translucency like in Corona or FStorm right inside VrayMtl. All of this could be done with a single VrayMtl.
https://forums.chaosgroup.com/forum/...orona-material


Regards,
-Eugenio

[Art48]

That's really cool workflow, gotta save it

[Richard7666]

I most likely would approach this material differently. Not that your setup is wrong, even because Peter is a great artist with lots of experience, but mixing Vray2Sided with VrayMtl using translucency inside doesn't make much sense to me. Also, as Vray2Sided is feeded with materials, this means it blends also reflection and other stuff, making things trickier than they need to be.

Although my nodetree may seem more complicated, it's actually much more logical as everything is properly separated. I use Vray2SidedMtl solely with diffuse textures on them, no translucency or reflection whatsoever in the VrayMtl inside. This makes 2 sided work predictably, then I use a VrayBlend to add a reflection on top of the translucent Vray2SidedMtl (for the coat, I make a VrayMtl with white reflection with no fresnel, and use a Fallof in Fresnel mode as a mask). So reflection is not dimmed or mixed in the 2Sided material. Then I use a VrayBumpMtl to add bump to everything so there's no need to instance maps between front, back and reflection layers. And the last step is the cutout, which similarly to bump, applies to everything underneath so no need to instance maps everywhere. I do that with a trick I've learned from Vlado sometime ago, with another VrayBlend with no base material (so it becomes non renderable), and my material is the coat, the mask of the coat is the cutout.

As I said, seems complex, but it's actually more logical and simple to work with IMO.

But all of this would be waaaay simpler if we had translucency like in Corona or FStorm right inside VrayMtl. All of this could be done with a single VrayMtl.
https://forums.chaosgroup.com/forum/...orona-material


Regards,
-Eugenio

How's the render speed on that?

[Midiaeffects]

Thanks for asking Richard,

I had to compare rendertimes and I was quite surprised that indeed my setup was much slower (2x). Seems somewhat illogical to me though. However, the most important part is that I did a more extensive testing regarding Vray2SidedMtl and in particular when using VrayMtl with translucency inside a Vray2SidedMtl. I will post my tests and conclusions in details on this topic.

Anyway, the good news is that the setup is actually much simpler, has normal rendertimes, and gives consistent results with Corona for example. The the downside is the reflection dimming because of Vray2Sided, as I don't use a VrayBlend to add a reflection layer. But I rather this way since Glossy Fresnel will work correctly and also because leafs are not super reflective, one can just compensate by increasing reflection power.

So, from my tests, the "secret" is to simply setup a VrayMtl *with* translucency (but no refraction) inside a Vray2SidedMtl, and control the translucency amount from there (in this case it's the default 50% gray). That's it.

Regards,
-Eugenio

[piotrus3333]

I remember this tutorial by Vlado helped me a lot:
http://help.chaosgroup.com/vray/imag...leaf_tutorial/

[PIXELBOX_SRO]

Mediaeffects:
but what do you do when adding a backside material to the leave? Youd need to ad some translucency map there as well no? To have a proper mix.