max transparency depth and alpha

[Julien BOLBACH]

Hi guys,

I'm experiencing issues with the max transparency depth and the resulting alpha. When Vray reaches the max transparency depth, it renders black with a black alpha as well. Is there a way to have an exit color of some sort to avoid this problem ?

Thanks a lot,

Julien

[ivaylo.ivanov]

Well, the max transparency depth is doing exactly what it says - it just stops the rendering when given depth is reached. If you've passed through fully transparent geometry, it will end up black of course. Why not just increase the depth?

[Yannick]

Hi guys,

I'm experiencing issues with the max transparency depth and the resulting alpha. When Vray reaches the max transparency depth, it renders black with a black alpha as well. Is there a way to have an exit color of some sort to avoid this problem ?

Thanks a lot,

Julien

In the material refraction, there is such option (Refraction Exit colour).

[vlado]

I'm experiencing issues with the max transparency depth and the resulting alpha. When Vray reaches the max transparency depth, it renders black with a black alpha as well. Is there a way to have an exit color of some sort to avoid this problem ?

We could return the environment color, but I'm not sure what alpha to return... perhaps leave as it is so far for the ray?

Best regards,
Vlado

[Julien BOLBACH]

Yeah, that would be amazing to do that !
It would probably induce a bit of flickering, but it's much better that having black spots.

Thanks,

Julien

[Julien BOLBACH]

Is it something that would be easily implemented in a nightly build ?

Thanks,

Julien

[vlado]

Yes, should be there by the end of the week.

Best regards,
Vlado

[vlado]

Actually should be done for the next nightly build tomorrow.

Best regards,
Vlado

[Julien BOLBACH]

Awesome, thanks a lot !

[Julien BOLBACH]

Hey guys,

We tested the bew nightly build, but its not giving a better result unfortunately.
I was wondering, could it be possible that once the ray hits the transparency limit, it's rendering the latest hit surface without transparency ? I guess that would be harder to implement, but it would be great for objects loke trees with a lot of transparent leaves.

Let me know what you think.

Thanks,

Julien

[vlado]

Will this not bring you to your original problem?

Best regards,
Vlado

[Julien BOLBACH]

Well not really. Here is an example, considering a tree full of leaves with transparency maps and color maps

- Behaviour right now : once vray hits the transparency limit, it stops the ray and the resulting pixel is black over black alpha
- Proposed behaviour : once vray hits the transparency limit, it renders the current hit object without transparency. In this case, would render the color map of the leaf (green) over a white alpha.

Does this make sense to you ?

Thanks,

Julien

[vlado]

- Behaviour right now : once vray hits the transparency limit, it stops the ray and the resulting pixel is black over black alpha.

Not quite; it will return whatever transparency if accumulated so far.

Does this make sense to you?

I'm afraid not. Would it be possible to get me an example scene?

(A side note: best to avoid transparency for tree leaves in particular. It's faster to have them as geometry.)

Best regards,
Vlado

[Julien BOLBACH]

I'll try to get you an example. I think this happens when the accumulated transparency is 0 (which is our case here).