Making convincing materials: which SHADER to use?

[nisus]

Hi all,

 

I'm starting this topic on Ken Waltons request:

Who got tips / rules of thumbs to share on the use of shaders?

 

rgds

 

nisus

[STRAT]

personally i use photos, bitmaps, scans from magazines etc...

 

in other words i use 'real' material.

 

i generally stay well clear of proceedurals as they generally look well fake and obviously used.

 

this is generally because ppl haven't mastered them properly, but even a seasoned pro's work with procs stand out.

 

imho max's proc shaders stink, c4d's are better but still reek of much of the same. and even plugs you buy like dark tree dont do much more.

 

the way to make proper photoreal textures , IMHO, is to use real source material as i mentioned in my first paragraph.

 

Dont be afraid of using real photos of skys, bricks, concrete, wood etc..etc..

 

ok, so you'll need to do (in most cases) extensive photoshop work to them to make them look real in you renders, but why struggle with shaders or painting ur own textures when the world is out there just waiting for you to point ur digicam at it???

 

or are you looking more for tips and tuts rather than a point of view?

 

[edit]

just as a foot note, pressing F1 will give you a very good description of shaders and their uses. there aren't any steadfast rules for using them, just try them out and experiment.

[edit]

 

[ October 15, 2002, 03:11 AM: Message edited by: STRAT ]

[Dave Buchhofer]

Well, I'm very very far from mastering materials at all, but in my opinion Procedurals are the way to go for many things. If used well, they can do wonders with the tiling issues faced by using image mapping..

 

Its very dependant on what you're trying to do however.. And it all comes down to attention to detail really. Learn how to look at what you're trying to make and divide it up into its seperate "layers" and you can make just about anything.

 

Personally, I'm becoming quite fond of Darktree by Darksim.com.. Filling in large expanses of tiles/wood/whatever is fairly simple.. controling where/what the detail is in a certain area is a bit more tricky, and probably more leaning towards the images based texturing side.

 

In VIZ, materials should follow somewhat along a real world reflectance scale:

 

Typical Material Reflectance's:

 

Material - % Reflectance

 

Metals:

Aluminum - Brushed -- 55-58

Aluminum - Etched -- 70-85

Aluminum - Polished -- 60-70

Stainless Steel -- 50-60

Tin -- 67-72

 

Masonry:

Brick - Dark buff -- 35-40

Brick - light buff -- 40-45

Brick - Red -- 10-20

Cement - Gray -- 20-30

Granite -- 20-25

Limestone -- 35-60

Marble Polished -- 30-70

Plaster white -- 90-92

Sandstone -- 20-40

Terra-Cotta - White -- 65-80

 

Glass

Clear or tinted 5-10

Reflective 20-30

 

Ground cover:

Asphalt -- 5-10

Concrete -- 40

Grass/Vegetation -- 5-30

Snow -- 60-75

 

Paint:

White -- 70-90

White porcelain enamel -- 60-83

 

Wood:

Birch light -- 35-50

Mahogany -- 6-12

Oak - dark -- 10-15

Oak - light -- 25-35

Walnut -- 5-10

 

[ October 15, 2002, 04:00 PM: Message edited by: Dave Buchhofer ]

[Dave Buchhofer]

(A question that came up on the VIZ boards also, figured i'd kill several birds with one tutorial.. Heh.)

 

>>How Do I create realistic, clear, reflective glass?

 

***

 

Hi Dave,

 

I removed your little glass-tutorial inhere as this is a topic about shaders (Blinn, Phong, Metal,...). I did place your tips in the GLASS MATERIAL topic, in the same part of the forum (Tips&Techniques)

 

rgds

 

nisus

 

[ October 17, 2002, 04:10 PM: Message edited by: nisus ]

[STRAT]

nice tut that, but unless i missed sommit you neglected to mention another important feature to consider when making glass (particulaly larger pains) - distorting the reflection through the bump map channel.

 

glass will have a slight distortion to it depending on it's make-up, size and fixing.

[ingo]

OK, one for bitmaps and one for procedurals. Now i recommend to use both

Use the photo as a base and than add procedurals so you cant see the repeating tiles and add more variation. And dont forget to use some of them for Alpha channels for others. Not to forget too use them for specular channels.

You may end up with six or even more texture layers in the color and/or the diffuse channels, and a few ones in the specular, reflective and bump channles, but its worth the try.

Depending on what software you use procedurals normally render a little bit slower than bitmaps, as long as you dont use higher resolution bitmaps .

 

ingo

www.im-graphics.com

[DaveC]

Hiya,

 

I'm having trouble with shaders in 3DS Max. Simply, reflectance and transmittance seem to be locked at 100% all the time. Are these accessible through the material editor in general, or are these values calculated from the variables you input into the diffuse specular etc etc...

 

Also, for a daylight solution using radiosity in 3ds, what kind of meshing size (metric) is suggested overall. I'm quite new to using radiosity, so general ball park numbers for a small city scape would be handy...

 

Also, which Max shaders do I want to be using, Phong, Blinn, and what kind of "general" settings, like the ambient and diffuse especially!!! Getting some odd results with nomral looking ambient levels.

 

Cheers

 

Dave

[Zortea]

Hi everyone...

my problems are:

first: I can´t start a new topic on this part of the forum, so it will runs here...

second:

How can I make this kind of material?

its a kind of transparent plastic...

[bryan lym]

I have had many troubles using radiosity/advanced lighting in MAX 5 due to color bleed, which is obviously related to reflectance scale.

 

You can set the mat'l editor to show reflectance scale and then from reading up on the issue in the help files regarding color bleed I learned to turn down these values.

 

The biggest help was loweing the RGB output of the bitmaps. For instance, a dark reddish wood bitmap on furniture was turning the ceiling tiles very reddish and that doesn't happen in real life. Turning down the output really helped.

 

If you haven't checked out the architectural materials in MAX 6 you should. I'm using MAX 6 now and I am very pleased. It is much more along the lines of the Lightscape materials using shininess and letting you set a default such as "semi-gloss paint" or "varnished wood" and them tweaking the settings and assigning maps.

[Chirag Kadiwar]

Hello Dave,

 

I read you mentioning about Darktree by Darksim.com .I have looked into their website before but couldnot make up mind to whether purchase it or not ,can u please guide me a little on that and maybe throw some light on Darktree.

 

Thanks

-Chirag

[Frosty]

Like strat, ace and a few others (Ernest are you among us yet?), I'm a Cinema 4D user.

 

I dont think software determines which method to use... just thought I'd preface with that.

 

I think the decision as to image based or procedural depends on the task at hand. Most of the time I blend the two. For glass, plastics and paints, I almost always use procedurals. For woods, cements, corrugations, I almost always use images. And as ingo suggests, I find it useful to use procedurals to mask the tilings of images. Various noises layered on top with alphas or in seperate channels like diffusion.

 

A good collection of grunge/rust/flake maps can help in this tremendously as well. I have a small collection I shot in a mine - I'll share them all when I have a chance (too busy now). I hope to add to this collection at Christmas when I may get to go under ground