Maya: Raytracing Tutorial, Wine Glass

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glass_compare

Arnold Renderer

Maya Renderer

Mental Ray Renderer

Revolve a wine glass shape, place it on a plane.

Turn off Color Management:
Select Windows->Settings/Preferences->Preferences
Select Color Management
Uncheck Enable Color Management
Select Save


Rendering with Arnold
Do some test renders with raytracing before you make the glass transparent to get the shadows where you want them.

Find a photograph of a glass you like for reference.

Raytracing is a type of shadow rendering where the path of individual  light rays are calculated from their source (the light) to their  destination (the camera). It can produce soft and transparent shadows.
Raytracing is done automatically with Arnold

hypershade   Windows->Rendering Editors->Hypershade
I
n the hypershade window, add an
aiStandardSurface under the Arnold Shader node.

Select the wine glass from the scene.
Turn off Opaque under the Arnold drop-down in the Attribute Editor

Click the 
aiStandard Surface shader ball.
Under Base set Weight to 0.8 and Metalness to 0.15  (reflectivity, default .8 and 0)
Under Specular, set Roughness to 0.1  (default .1)

Under Specular, set IOR (Index of Refraction) to 1.5, or 1.1 for thin glass   (default 1.52)
Under Transmission set Weight to 1  (default 0, this makes it transparent)

Select a model.
Use the right mouse key over the shader ball to bring up the marking menu, select Assign Material to Selection



Lights
To get highlights, use a Maya Area light with a tall and thin scale, following the proportions of the wine glass.
(The maya Area light has nicer highlights by default.)

Under the Arnold attributes of this light, set the Exposure to 8

Add an Arnold->Lights->Skydome light for ambient light
Set the color to 50% grey



Note:
When rendering transparent and  refractive surfaces in Arnold, the normals of the geometry need to face in the right direction.


Render Settings Arnold
Press this icon upper middle right  srender_settings

With these settings below, your scene will render faster with a preview quality.
Under the Arnold Renderer
tab:
Under the Sampling arrow:
     Set Camera (AA) to 3+      (default 3 removes grain)
     Set Diffuse to 1     (default 2)
     Set Specular to 1      (default
2)
     Set Transmission to 2      (
default
2, controls transparency and grain)
     Set SSS to 1      (
default 2)
     Set Volume Indirect to 0      (
default
2)

Under the Ray Depth arrow
     Set Total to 4      (
default
10)
     Set Diffuse
to 1      (
default 1)
     Set
Specular to 1      (
default 1)
     Set Transmisssion
to 4      (
default 8)
     Set Volume
to 0      (
default 0)
     Set Transparency Depth
to 4      (
default 10)

Click Close
to close the window



Rendering with Maya Software Renderer

Do some test renders with raytracing before you make the glass transparent to get the shadows where you want them.

Find a photograph of a glass you like for reference.


hypershade   Windows->Rendering Editors->Hypershade
In the hypershade window, add on a Phong Shader .


Double click the 
Phong shader ball to see the attributes..
Adjust Color to black.
Adjust Transparency, double click on the black color box to bring up the menu.
    
In HSV mode
    
input .9 as the value (V)

Under Specular Shading:
Input Cosine Power 100
Djust Specular Color to white
Input Reflectivity .2

Under Raytrace Options:
Check Refractions
Input Refractive Index 1.3
Input Refraction Limit 10
Input Surface Thickness  .4
Input Reflection Limit 1

Assign the shader to an object in the scene.



Lights
To get highlights, use a Maya Area light with a tall and thin scale, following the proportions of the wine glass.
Under Raytrace Shadow Attributes
     Check Use Raytrace Shadows
     Increase Shadow Rays to 20 or more only for Area Lights
     Ray Depth Limit 2

Add an Arnold->Lights->Skydome light for ambient light
Set the color to 50% grey

Select the persp view, select View->Camera Attribute Editor... from the view menu
     Under Environment in the Attribute Editor, make the Background Color 50% grey



Press this icon upper middle right  srender_settings
Change Rendering Using to Maya Software
Under the Common tab:
Under the Image File Output
arrow:
Choose Image format: Tiff

Under Maya Software tab:
Under Raytracing Quality
    
Check  Raytracing
    
Input Reflections 1
    
Input Refractions 6
    
Input Shadows 2
    
Input Bias .2 This will make round objects look less jaggy.




Rendering with Mental Ray

Do some test renders with raytracing before you make the glass transparent to get the shadows where you want them.

Find a photograph of a glass you like for reference.


hypershade   Windows->Rendering Editors->Hypershade
In the hypershade window, add on a Phong Shader .


Double click the 
Phong shader ball to see the attributes..
Adjust Color to black.
Adjust Transparency, double click on the black color box to bring up the menu.
    
In HSV mode
    
input .9 as the value (V)

Under Specular Shading:
Input Cosine Power 100
Djust Specular Color to white
Input Reflectivity .2

Under Raytrace Options:
Check Refractions
Input Refractive Index 1.3
Input Refraction Limit 10
Input Surface Thickness  .4
Input Reflection Limit 1

Assign the shader to an object in the scene.



Lights
To get highlights, use a Maya Area light with a tall and thin scale, following the proportions of the wine glass.
Under Raytrace Shadow Attributes
     Check Use Raytrace Shadows
     Increase Shadow Rays to 20 or more only for Area Lights
     Ray Depth Limit 2



Select the persp view, select View->Camera Attribute Editor... from the view menu
     Under Environment in the Attribute Editor, make the Background Color 50% grey



Press this icon upper middle right  srender_settings
Change Rendering Using to Mental Ray
Set Overall Quality to 1

Change Indirect Diffuse (GI) Mode to Finalgather
Filter Size 1.000 1.000

Under Trace Depth
     Diffuse 2
 
   
Glossy/Spec Reflections 1
     Glossy/Sec Transmissions 6
     Max Trace Depth 6