Need help

[Doug Armand]

I'm certainly no expert but my understanding for this is that Indigo is an unbiased render - ie uses real-world physics to compute the image and I don't think there is a double-sided anything in the real world as everything has some volume no matter how small or thin?

Thats how I read it anyway - I'm sure one of the technical bods will be along any second to show that I am wrong however

[Headroom]

Why should i waste my comp resourses that are small enough already? Its simply unproffesional to do this.

Exactly! The double-sided-material-feature may help you in creating the desired effects, however, I believe your assumption that this is the only way to do it may not be correct. As others have pointed out this feature is not currently present and I am sure there are other users that may be able to help you creating an equally convincing effect without that particular feature just by using the already present tool set without overly straining you computational resources.

It still would be a good Idea to post what you are trying to achieve, perhaps a screen shot of the scene

[slam_k]

If you think so than by your logic i should texture them from both sides ,that will either decreace quality of image or once again lead to needles powerloss.

Even smartest people in this world dont know how exactly our world works for sure,indigo might simulate via visuals.it might be using one of theories about light i guess.

It will be quite difficult to texture thin volume model of leaf and physically right it should have front and back side and plus to it something like veins in the volume.So indigo right now dont have possibility to add texture inside volume. It uses diffuse map as scatter subsurface light, and its not physically right.

If you want idigo as a home-based render you can leave it be as it is. But i see unbiased renderers as progressive renderers that will become faster and their future in production rendering. Ive studied many renderers since 2002 and i find indigo most realistic of unbiased renderers and also as fast without post-processing.

I understeand that i dont have possibility right now to do as i want and i will just post my image anyway when im done with it.

Headroom, i dont want to use any tips and tricks if you can do it in alot easier way. =)

Anyway thanks for answers guys.

[Headroom]

It uses diffuse map as scatter subsurface light, and its not physically right.

That is incorrect! Indigo supports true subsurface scattering, however, that obviously needs a volume and is also quite time consuming to compute.

Thus a technique that many users employ for foliage is to use a material blend of a phong and diffuse transmitter as an approximation. The phong material component would simulate the shiny surface of the leaf and will produce reflective highlights. The diffuse transmitter will then create the translucency of the foliage when sun shines through it. IMHO that produces quite convincing foliage.

You can call that a trick. I'd call that a tool (indigo) specific technique. I have been interested in Computer Graphics for over 20 years and it would occur to me that most of the successful artists have gotten successful by finding and getting very comfortable using a set of particular tools that work for them and contribute to their workflow. That usually involves some tricks and tips and workarounds that are perhaps not obvious to the occasional user.

[galinette]

We definitely understand that the wish list and roadmap is long, but this is definitely a very valid request... You simply cannot just say "there are nice trees in the gallery, so live with it or duplicate the polygons" while staying a commercial software.
Not mentioning that duplicating leaves while having diffuse transmission will increase a lot render times and noise as light will do multiple bounces within the two polygons...

Etienne

[StompinTom]

It makes good sense to have a Double Sided material, especially if we already have the Diffuse Transmitter material. The Diff. Trans. material is essentially simplifying the equation by assuming that the scattering volume has a negligible thickness and very high scattering, so it is a shortcut. The same could be said of the Double Sided material, it's simply assuming a negligible thickness for a volume that has different properties on its two sides (and ignoring edges, which approach 0 anyway because of the insignificant thickness).

Hopefully we'll see something like that in Indigo soon!

[galinette]

The difficulty of it is that double sided materials allow, if you are not careful, non symetrical transmission (BTDF not the same on two sides) which is absolutely forbidden by physics and may provide weird results. Finding a material interface flexible enough but satisfying that constraint is not straightforward.

For instance, one could allow only the non transparent materials (diffuse, phong, oren nayar) to be double sided. Then, they could be gloabally blended with a transmitter, the blend affecting both sides. This way, the rule would not be enforced.

[Headroom]

I did not say in any way that the request for an double-sided material is invalid or would make no sense! It appeared to me, however, that there was an insistence that realistic foliage can only be achieved by using a double sided material.

Based on what I've seen on this forum I find that not to be the case.

BTW, I have quite a wishlist myself. A road map has yet to be published