Grant Warwick- Mastering Vray: Material Ideas Needed.

[davision]

Thanks for the response Joe. Sounds like we're thinking along the same lines.

So you'd agree that theoretically it doesn't make sense to have the same map in glossiness and in bump?

[joconnell]

Yeah - I think that glossiness is a polish effect overall so you can have smeared effects (finger prints on glass as an example) which wouldn't cause the surface to actually raise in any way. You might use a bump and glossiness map if you were doing something like a mix between two different materials like dirt on a surface which is really mixing between two totally different surface types. Looking around my desk at the minute, I've got a leather surface and lots of plastics. For the (p)leather desk surface I'd use a bump for the actual cellular pattern and then use a single glossiness value to start. The bump will change the normals of the surface and make the little valleys receive light differently to the flat sections so that'll likely be enough to give me specular variation. If you were to use a glossiness map there too, it's not as if the little valleys are made out of a different material or would have different properties than the flat facing parts so why try and map variation in there? Toitally different situation if you're doing something like the indents in a surface collecting dirt or dust but then you're again looking at mixing between two totally different materials.

[AlexP]

Interesting points, never really thought about it that way. Makes sense though, Ive a bad habit of just instancing the one B&W map to all the applicable slots, quick to set up but incredibly inefficient for render time I would imagine.

[joconnell]

Yeah, the glossiness slot is pretty sensitive. I'd instance maps sometimes but have the instance fed through an independent colour correction or output map first so I can control the black and white points of the map.

[Neilg]

i've taken to dropping my glossiness map in a mix-amount slot and controlling the limits through there - gives a more exact control than a CC.

[joconnell]

Yeah. I think bertrand always uses a full range bitmap that goes from black to white for everything, then you can just use the black point and whitepoint on the output curve to make your values easily, kind of a similar idea. I like your idea though since you only really need minimum, maximum and contrast on the ramp between the two. Nicking that one

[stevesideas]

Guys the GGX model is already in the nightlies and it's great

This is great news ! Any examples to show us ?

[Pixelcon]

Erm. I would but my one render node (grrr vray 3!!) is being used overnight by my workstation at work...

I could upload an image but it sort of doesn't make sense without a side-by-side comparison of one of the other BRDFs

Sorry!

[voltron7]

Wow, a lots of great interesting discussions going on here, and I may take flame for this, but could this get cleaned up?
100+ pages, and maybe only 12 are actually material ideas for Grant, lol.

Maybe some of the posts could be moved to appropriate forum sections, like Off topic and Render Theory?
Not trying to be a party-pooper :P
Okay, flame-on

[soulburn3d]

You're quite right about bump really being the driving factor of glossy or sharp reflections but it's at such a fine level, it's not something that we could really do with a bitmap or pixels. If you had a bump map fine enough to capture this level of micro facetting, vray's anti aliasing would just blend this into a flat grey value as it's well below sub pixel sizes. Neil did a tutorial or a run through showing using a really fine bump map as a way of getting glossy reflections I think?

Yup, in the real world, bump drives a lot of this stuff, but getting that result in cg from a bump map is very difficult / very slow to render in any renderer. So for my work I tend to rely on the spec map to do a lot of the work, and the bump more for scratches and tiny lumps.

- Neil

[soulburn3d]

i've taken to dropping my glossiness map in a mix-amount slot and controlling the limits through there - gives a more exact control than a CC.

That's a good work around. But what we really need is a color correction map that has a proper remap function.

- Neil

[joconnell]

The gradient ramp in mapped mode might be interesting to look at but I totally agree. I'd love chaos to do a proper color correction map or autodesk to at a minimum buy cuneyt's plugin. Their map utterly trashes the colour data, it's as if no one ever actually tried using it before they shipped it out!

[davision]

I used to use Cuneyt's tool back in the day (miles better than max's late-to-the-party failed attempt) -- but I always got nervous when upgrading max as to whether the plugin would get updated. I think one year it took a while before it was recompiled. Like right now, I don't see max 2015 listed as an option on his main download page.

[soulburn3d]

Yup, that's the danger of using 3rd party plugins. But the colorcorrection node in base max is so bad, I really feel that even skipping a max release to continue using color correct is worth it.

- Neil

[anchovy]

Grant-

Ive been enjoying the course and am just catching up on the thread here. So if Ive missed it please forgive me but id love to see youre take on very prominate micro scratches in metal like we see in this thread on the maya side

http://forums.chaosgroup.com/showthr...lossy-Surfaces







or as you see in this reference. Its a trick to get a clean result for sure.

Thanks!

-Michael