[REQ] material shaders enhancements

[Pibuz]

Hi guys, I know I've been bugging you all developers for a long time, but I wouldn't want this to sink into oblivion: I suggest two basic shader improvements.

1. Add a "falloff" shader to simulate velvet materials without having to mess around with maps and microstuff;
2. Add a "coating" property to make a surface reflective with a certain amount of accuracy.

In my opinion, these two things would enhance the shaders section A LOT.
But I'm no expert, maybe they can't be done.. I'm open to all kinds of answer

Thank you Glare

PS. ..btw, the diffuse transmitter development has been keept in mind in the recent releases? I kinda find some troubles getting it right for leaves and curtains, but maybe it's a SkIndigo-related issue..

[CTZn]

2. Add a "coating" property to make a surface reflective with a certain amount of accuracy.

Hi Pibuz, could you explain this to me ?

Normally Phong materials are used for this purpose, what is it that they are lacking for you ?

Thanks !

[Zom-B]

The falloff shader already exists and easily done in ISL.
Cindigo provides some ISL Shaders that get integrated into C4D like other internal shader that use ISL Code in the background but have some easy to control Shader GUI for the Artists.

The ISL Noise Shader inside of C4D

I attached a Falloff Material, where you can extract the ISL code if you like
(credits to this material go to fused!!)

Example render of the Falloff material

Coating is something I would like to see at some point in Indigo too. Mitsuba has some great looking examples for that, just check out the great manual for examples: http://www.mitsuba-renderer.org/documentation.pdf

[CTZn]

Thanks for the insights Zom-B. Coating is like blending two phongs sharing the same albedo ?

om nom nom bsrdf's !

edit: nice example.
edit 2: Phong has a <fresnel_scale> parameter, I've never seen it exposed but it's perhaps worth inspecting...

[Zom-B]

edit 2: Phong has a <fresnel_scale> parameter, I've never seen it exposed but it's perhaps worth inspecting...

Afaik fresnel_scale introduced in v0.5 but was dropped during pre v1 Indigo time... no idea what it does here -.-'

[Pibuz]

2. Add a "coating" property to make a surface reflective with a certain amount of accuracy.

Hi Pibuz, could you explain this to me ?

Normally Phong materials are used for this purpose, what is it that they are lacking for you ?

Thanks !

Hi CTZn! You're always SO fast to answer!
By coating I mean a simple check to add a specular thin surface to whatsoever shader, just on top of all the sub-stacked "layers" (bump, exponent and so on..).
It gives you sort of a "blend" result but without the mess of making another material then blend two sub-materials, then find the proper amount of blending..Sometimes this process tend to be a little annoying.

To reply to ZomB, maybe ISL shaders are well implemented in some exporters, but in SkIndigo still it is something a little unclear, maybe because to use it you must learn some aknowledgments of math. It still has a too-professional approach. I'd like better to see a simple shader, which once selected could bring out something similar to what you attached (seems to be a very user-friendly panel).

Given that it's so simple to make a falloff material, can I ask you if you could do a rapid test of making a simple black velvet material using fused's shader? Just to have an idea whether that shader is able to make what I'm aiming for..

[CTZn]

edit 2: Phong has a <fresnel_scale> parameter, I've never seen it exposed but it's perhaps worth inspecting...

Afaik fresnel_scale introduced in v0.5 but was dropped during pre v1 Indigo time... no idea what it does here -.-'

I take it it must be a multiplier for the reflections, the context has still to be investigated ^^ perhaps does it come in place of IOR (wich would then take precedence by default)...

Back to the coated material in Mitsuba, from a non educated point of view I would believe that the alpha value is the difference in IOR's, and the depth could be figured by the blend value (with different albedos this time).

I'll have little time today to investigate on this

By coating I mean a simple check to add a specular thin surface to whatsoever shader, just on top of all the sub-stacked "layers" (bump, exponent and so on..).
It gives you sort of a "blend" result but without the mess of making another material then blend two sub-materials, then find the proper amount of blending..Sometimes this process tend to be a little annoying.

How I would do that really ? Well, I would duplicate the phong surface and make it a specular with a linear displacement. Heck I bet a coated material would be easier !

Hi CTZn! You're always SO fast to answer!

I'm a mess

[Zom-B]

To reply to ZomB, maybe ISL shaders are well implemented in some exporters, but in SkIndigo still it is something a little unclear, maybe because to use it you must learn some acknowledgments of math. It still has a too-professional approach. I'd like better to see a simple shader, which once selected could bring out something similar to what you attached (seems to be a very user-friendly panel).

As my example screen of C4D shows there is the possibility for exporter writers to code internal shaders with GUI that use ISL in the background, there is no hacking with code in the example noise shader, very user friendly, please re check the screenshot
Maybe something similar is possible in Skindigo and other exporters too

Given that it's so simple to make a falloff material, can I ask you if you could do a rapid test of making a simple black velvet material using fused's shader? Just to have an idea whether that shader is able to make what I'm aiming for..

something I could give a try, but not for today... anybody else is invited to do so

For the layered material, Lux just did some progress on this area too, check out the dev thread: http://www.luxrender.net/forum/viewtopi ... =10&t=7246

[Pibuz]

I'm here again with a quite strange request (thought I could add it here, instead of making a new topic): since I work with Indigo and SkIndigo, I actually lack a kinda cool feature: hair and fur. I know there are some nice plugins like "fur" and "componentspray" which somehow reproduce that effect, but I was thinking: could there be some way to codify a furry shader, or something? This way, one could set a plain colour or a texture as a base inside SketchUp (with no additional poly weight) and then adjust some parameters (inside SkIndigo or later on directly through the Indigo GUI) like direction, density, bending..

Could it be possible?

Thanks a lot!

[FakeShamus]

I've been thinking a hair primitive would be a great addition to Indigo. Maybe with parameters for thickness, flatness, so it could be adapted as grass or fur, or whatever. Especially with several modeling programs giving you built in hair options, but no direct translation into indigo to render them.

[Voytech]

I third this proposition! Please consider adding fur to indigo.

[Zom-B]

Hair is something nice on the Portfolio, but not used so much among artist as you maybe think guys... I have 1001 other ideas to enhance Indigo with features that kick in my day by day work

...but no direct translation into indigo to render them.

Grab some RAM for Xmas and render it as a mesh, you can also use most hair engines to place actual meshes on a surface that can be instanced...

[CTZn]

No worries, that request is tracked and has a ticket number.

To be more precise I've been pushing a bit for curves support, then implicit surfaces, such as the current sphere primitive in fact. But based on curves...

Then we'll ask for a tip and base width, and perhaps we'll have the choice of an interpolation curve... all speculative yet

I'll bump shaders edition unstable on some parameters (blend, >phong exponent !<),
finish on param implementation (huge enhancement for users toward ISL materials)
make ISL shaders named nodes (shareable among materials)

• eventually linking them as "let" statements ?

cheerios !

edit: well now the hair primitive is a tracked feature, before it was just a discussion. thanks for the heads up !

[FakeShamus]

I use hair quite a bit, actually, and grass seems to be very much in demand (plus, people are always struggling with it).

I've always use instanced meshes for hair and that works fine, but the hair particle system in blender allows for combing, clumping patterns, stuff that gives you much more control and natural variation than the instancing method can do. and with that capability in Indigo I think it would be the best looking hair and grass ever rendered.

[CTZn]

Sorry, you meant instancing.

I was on a different line (curve support).

*hold on I'm getting documentation on blender's hair system...