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Raytracing Tutorial Wine Glasses
Arnold, Maya Renderer, Mental Ray

raytrace_wine1

Photo

Arnold Renderer

raytrace_wine2

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
Find a photograph of a glass you like for reference.

hypershade  Windows->Rendering Editors->Hypershade

In the hypershade window, add an Arnold aiStandardSurface.

Select the wine glass.
Pre Maya 2019: Use the Attribute Editor, turn off Opaque under Arnold.
Use the Hypershade window, with the wine glass selected.
Right mouse key over the shader ball, select Assign Material to Selection.

Click the aiStandardSurface shader ball.
     Under Base set Weight to .8 and Metalness to 0.15
          (adjusts reflectivity and shadow color, defaults .8 and 0)
     Under Specular, set Roughness to 0
          (default .1, it will render faster, this adds a fogginess to the glass)
     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)

Lights
To get long highlights, use Arnold->Lights->Area light, scale it tall and thin scale, following the proportions of the wine glass.
     Under the Arnold attributes of this light, set the Exposure to 8
     Set Soft Edge .2

Add an Arnold->Lights->Skydome light for ambient light
     Set the color to 50% grey
     Turn off Cast Shadows and Cast Volumetric shadows

*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 2   (default 2)
   Set Specular to 1   (default 2)
   Set Transmission to 2   (
default
2, controls transparency and takes away grain)
   Set SSS to 1   (
default
2)
   Set Volume Indirect to 0   (
default 2)

Under the Ray Depth arrow
   Set Total to 8   (
default 10)
   Set Diffuse
to 1   (
default 1)
   Set Specular
to 1   (
default 1)
   Set Transmisssion
to 8   (
default 8)
   Set Volume
to 0   (
default
0)
   Set
Transparency Depth to 3   (effects the shadows,
default
10)
Click
Close to close the window

Count the number of glass surfaces overlapping to determine the Total and Transmission.



Rendering with Maya Software Renderer

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

Use the Hypershade window, with the wine glass selected, right mouse key over the shader ball, select Assign Material to Selection.

Double click the
Phong shader ball to see the attributes..
Adjust Color to 50% grey.
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 .1

Under Raytrace Options:
Check Refractions
Input Refractive Index 1.3
Input Refraction Limit 8
Input Reflection Limit 1



Lights
To get highlights, use Create->Lights->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, this gets rid of the noise.
   Ray Depth Limit 2

Add Create->Lights->Ambient light  for ambient light, place diagonally opposed to the area light.

Set the color to 50% grey

Add a giant sphere for the background.


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 8
  
Input Shadows 2
  
Input Bias .02 This will make round objects look less jaggy.


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