Microsoft KB Archive/184934

HOWTO: Antialiasing in Mental Ray

PSS ID Number: Q184934 Article last modified on 04-30-1998

IRIX:3.7,3.71; WINNT:3.7,3.71

IRIX winnt

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The information in this article applies to:

 SOFTIMAGE 3D for IRIX, versions 3.7, 3.71 == SOFTIMAGE 3D for Windows NT, versions 3.7, 3.71 == 

= SUMMARY =

This article offers antialiasing settings that produce the best rendering results.

= MORE INFORMATION =

Mental ray offers an antialiasing technique that allows you to specify two levels of antialiasing. The scene’s small features are tracked and the number of rays is automatically adapted to the appropriate level between two values that you specify.

For standard-quality renders (comparable to the adaptive 2 setting in SOFTIMAGE 3D), settings that produce the best results are -1.1 and 0.1.

For high-quality renders, a setting of 0.2 produces the best result. You can use a setting of 3 or 4 if it is required, but the render time grows accordingly.

A negative value allows mental ray to do under-sampling, which produces a smoother look within the object as opposed to supersampling (which affects the object’s edge).

A common application of under-sampling is with motion blur. Using the default antialiasing setting, the motion blur in mental ray does not produce smooth results. To produce a smooth blur, set Antialiasing to Gaussian minimum sample of -1 and maximum sample of 2. The negative value in the minimum sample (undersampling) eliminates the grainy look inside the blur area.

Try to avoid using settings with a wide range between the numbers (for example, -1, 4). Settings such as these cause mental ray to generate excessive buffer data and increase the memory comsumptions. Unless render time is not an issue, use settings where the maximum difference is not greater than 3.

Undersampling is not the optimal method to smooth motion blur because it increases rendering time. You can use the -time_contrast option, which you can add to Ray.irix5 (on IRIX) or Ray.exe on Windows NT.

= REFERENCES =

For additional information on the -time_contrast option, please see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: Q184917 TITLE : HOWTO: Reduce Motion Blur Calculations

If you have any questions concerning the information contained in this article, contact support@softimage.com by e-mail.

= Additional query words: =

Keywords : kbnokeyword Version : IRIX:3.7,3.71; WINNT:3.7,3.71 Platform : IRIX winnt Issue type : kbhowto ============================================================================= Copyright Microsoft Corporation 1998.