building some special metal material

[thengineer]

hi guys!

I'm currently working on a material/shader that looks like the following metal:
http://img109.imageshack.us/img109/7519/echteslampenmatda4.th.jpg (http://img109.imageshack.us/my.php?image=echteslampenmatda4.jpg)

My version:
http://img126.imageshack.us/img126/9228/lampenmattest3cgi1.th.jpg (http://img126.imageshack.us/my.php?image=lampenmattest3cgi1.jpg)
It's based on the A&D mat.

It's not the best, thats why I'm asking you for advise.
I've also tried out Jeff's nickel material, which comes really close:
http://www.pixelperfectgraphics.biz/cg_files/Nickle-2.jpg
(I hope Jeff doesn't mind posting his sample here)

The problem is, that his material is so slow due to the uber high sampling rate in the metal shader.

I hope you can give me some suggestions on how to improve my material.

greetings,
Jack

[JeffPatton]

Should be fairly easy to make that with the A&D material. I'd start with the chrome preset and then turn on the metal option, set the diffuse color to almost white (or maybe use a noise map/cellular map there for the grain)

Then adjust the glossiness to 0.3 or less, and set your glossy samples to 48 or higher for a smooth reflection. Maybe even add a noise/cellular map in the color swatch to add some grain to the reflections.

You might want to try the highlight & FG only mode for faster rendering (but less realistic reflections of course)..but either way it'll be waaaaaay faster than that old nickel mat.

You may also want to increase the 0 deg. refl setting (in the BRDF rollout) to .9 for brighter reflections.

And above all...make sure you have a proper environment (.hdr or a model, etc)...anything reflective will only look as good as what it's reflecting.

[thengineer]

okay, I've updated my material to fit your suggestions.

As a bloody noob, I didn't manage to put a HDRI map onto the teapot. But at least I have changed some of the light's colors.

http://img186.imageshack.us/img186/2738/matsettingsdr2.png

http://img19.imageshack.us/img19/8200/mt5oq4.jpg


edit:stupid me, I was just missing an option, for the HDRI enviroment. updated image follows.

[JeffPatton]

Problem: you have your "reflectivity" amount set to .23 which is not very reflective at all. Hence your material doesn't look like metal right now...You need to increase that to the 0.9 to 1.0 range.

[F3LIC3]

Your "Custom Feflectivity Function" is also incorrect, because
all materials are more reflective viewed from a smaller angle.
So the value "90 deg refl." must be higher.
Another solution to achieve this grainy look is to set the "Glossy Samples" value lower I think.

[thengineer]

okay, i believe things are getting more clear to me: i though the normal reflectivity value has no function since there is a BRDF rollout anyway.


anyway here is another update: i think it looks better now. maybe I'll have to fine tune the reflectivity sampling rate.
http://img292.imageshack.us/img292/5034/mt5iik5.jpg

[JeffPatton]

Good eye! I didn't even think to look at his brdf curves since I didn't mention changing those in my first reply to him. :(

[JeffPatton]

Attached some settings.

http://jeffpatton.net/Blog-images/light2.jpg

Looks like you need a lower glossiness setting than I originally thought. But on the good side you can use the fast(interpolate) setting to really speed up the render. Even though I used 256 samples...it rendered quickly due to the use of interpolation.

[F3LIC3]

Very beautiful mat Jeff!
But how did you make the grain now?
I thought if you use so many "Glossy Samples" the reflection would be smooth. Or is it because of the "fast interpolation"?

[thengineer]

Thanks Jeff for your effort! I have set the glossy reflection samples to 100 and it takes 1.5hrs to render. when using the interpolation method render time goes down dramatically without changing the appearance of the material.

I'll post my version of the lamp with the material when it's done.

For now I say thanks to you and F3LIC3!

[kevjon]

I've been looking for a solution on how to create a good looking smooth aluminium material using A&D materials.

This thread had provided all the clues, thanks Jeff!