Search Maya Zest

Saturday, September 17, 2011

Detailed Brushed Metal Anisotropic Shader tutorial (maya)

First off Anisotropic shaders are bit tricky, how good they look has a LOT to do with the environment and lighting. You can have the greatest shader in the world but unless those other two factors are also perfect you WON'T SEE IT.


Here is a mix for creating an Anisotropic shader in Maya and Mental Ray. Be advised though depending on your situation, you will have to tweak the settings to make it work perfectly for you.

1. First open Hypershade: Window>Rendering Editors>Hypershade

2. Now create a new Maya node. The Anisotropic shader is under the surfaces category in the create maya nodes drop down of the hyper shade.

A new anisotropic shader called "anisotrpic1" will appear in the hypershade work area. You can rename it whatever you wish.

3. In your viewport right click and hold down the button on the object you wish to attach the shader to while holding down the button move to menues: assign existing material>anisotropic1

This will apply your material to the object.

4. Now let's create a quick area light to hit up our object with. Menus: Create>Lights>Area Light

Position the area light above pointing at your object.

5. Now we need to turn on shadows for the light. Select the light then in attribute editor go to the Shadows drop down then Raytrace Shadow attribute drop down. Then select the checkbox Use Raytrace Shadows.

Set Shadow Rays to 10.

6. Go to render options menu: Window>Rendering Editors>Render Settings. Make sure that Mental Ray is selected in the "Render Using" drop down at the top of the Render Settings Window.Then go to the Indirect Lighting Tab, Final Gathering drop down and ENABLE the Final Gathering checkbox.

I'm also just going to put a simple wood texture on the floor just to give us more reflections to play with in the scene. Do a render to see what you are getting.

Yeah it's pretty nasty looking, but let's keep going.

7. Go back to your hypershade and select your anisotrpic1 node. In the Attribute Editor under the drop down Specular Shading

DISABLE the Anisotrpic Reflectivity Checkbox. This will let you control the level of reflectivity yourself.

8. Change the Reflectivity value to 0.736

Then under Common Material Atributes change the Diffuse setting to 0.132

Under specular Shading set Speard X to 7.532 and Spread Y to 5.882

Roughness to .7

Fresnel Index to 2.0

Metal will only look good if it has something to reflect. So we are going to add some image based lighting. (IBL)

9. Go to render options menu: Window>Rendering Editors>Render Settings. Then to the Indirect Lighting Tab at the top of this you will see Image Based Lighting. Click the CREATE button next to it. Immediately an IBL node system will be set up in your scene, though it may look like nothing happened. Now click the Right pointing arrow to the right of the Delete button.

In the attribute editor it should open your IBL atributes. next to "Image Name" click the small folder to load and HDR file. These can be downloaded from many free sites online.

Navigate to your HDR file and click open.

The look of your metal will totally be dependant on which HDR file you are using but this is what mine looks like at this point.

Now we have nice anisotropic highlights but perfectly crisp reflections. Let's do something about that.

10. In the hypershade Goto create maya node, then under the 2D textures drop box select "As Projection" Then select the NOISE node in the list of 2D textures. This creates a new projection noise node. In the top of the attribute editor you can rename it anistropic_noise1 Now select the anistropic_noise1 node, and in the attribute editor make the following settings.

Threshold 0.1
Amplitude 0.140
Ratio 1.0
Requency Ratio 1.744

11. Next in hypershade select the place2Dtexture node attached to the noise1 node. In the atribute editor increase the "RepeatUV" fields to these values. U is first V second.

U set to 0.05
V set to 100

The purpose of creating this texture of just lines is to use it to blur our reflections in an anisotropic way. Profound huh?

12. Here is how to attach it. First in the hypershade select the anistropic_noise1 node. The atrtribute editor for it should display in the right side of the screen. Expand the Mental Ray drop down. You will see a Mi Reflection blur attribute.

Now in your hypershade MIDDLE house click and hold down on the projection1 node. Drag it over to the attribute editor and connect it to the Mi Reflection blur attribute.

A very busy looking connection editor will appear. In the left hand "outputs" list select OUTALPHA

Then in the right hand side of the connection editor select miReflectionBlur. and press close. (MAKE SURE TO SELECT REFLECTION Blur AND NOT reFRACTION Blur

Now let's render and see what we are getting.

Alright, the reflections are being blurred by the noise but it looks ghastly. We need to smooth it more.

13. To smooth grain of the reflection go to your select your anisotropic1 node in the hypershade then in the Attribute Editor expand the Mental Ray drop down and set the Reflection Rays setting to 50. This will give it a lot more quality.

Now let's see what we get.

Much better now we have something that is really starting to look like real brushed metal. But it is perphaps a bit to plasticy looking still. The solution to this is to add an irregular "darking map."

14. In your Hypershade under Create Maya Nodes, scroll down to the 3D textures drop down and create a new Cloud node. The cool thing about creating this as a 3D texture is that it will create an object in your scene you can then move around to change the surface properties of your metal till it looks just right.

Now make sure that you anisotrpic shader is selected and you are looking at it's attributes in the Attribute Editor on the right hand side. MIDDLE click and hold down on the Cloud node (not the place3d one) and drag it over to the Color attribute of your Anisotropic material. It should drop right in.

Now here is how it looks as you can see it has a much darker more natural metal feel. Especially at the edges. You can move the green 3D cloud placement node around in your scene to change the effect. Or select your cloud node and change the contrast etc to lessen or increase the effect.

That's it you should have a very good starting place for anisotropic metals with this shader.

Please check "HELPFUL" below if it was, if not COMMENT below and tell me why!