Autodesk 62205-051408-9001 User Guide - Page 735

Importing and Exporting Setups ❚❘❘ Grain from One Frame to the Next It is important to remember that grain pattern in a clip changes from frame to frame. Grain created by the Add Grain operator also changes from frame to frame. If you are holding a single frame for a static effect, you can add grain so that the image changes a bit. You will see the aggregate moving noise caused by the grain. If you get a lot of lighting changes within a clip, you may need to keyframe through several settings of the Add Grain operator. adjusting each one individually is far more accurate. 4. To change the horizontal size of the grain, drag the appropriate Radius X field for the selected channel. The range of values is from 0 to 100. 5. To change the vertical size of the grain, drag the appropriate Radius Y field for the selected channel. The range of values is from 0 to 100. Usually, the Radius X and Radius Y fields for a specific channel are the same or quite close. Adjust the Grain Size When you adjust the grain size, especially when you are trying to match grain, look at an area of intermediate brightness. The grain in dark areas sometimes appears larger than in bright areas because of bottom clamping. Since the Add Grain operator produces grain of uniform size for all luma values, it is better to first match the size with an intermediate luma value and then to boost the low luma control points by increasing their gain. This produces extreme clamping and results in a visually larger grain size for dark areas. The low luma control points are the leftmost control points in the granularity curve. To adjust the grain size: 1. Show the Add Grain controls. 2. Enable Exclusive to show the selected channel as grayscale. For more information about the channel buttons and Exclusive button, see Apply the Add Grain Operator. 3. Disable Proportional below the Radius X and Radius Y fields to adjust the channels independently. You can apply changes to all channels simultaneously by enabling Proportional, but Importing and Exporting Setups You can import and export setup files for the Add Grain and Remove Grain operators. Usually, you do this to transfer a setup for a specific shot between Combustion and one of the Autodesk SGI-based systems (for example, Flame). Note: On the Autodesk SGI-based systems, Add Grain is named Regrain and Remove Grain is named Degrain. Exported setups are saved as ASCII files with a .regrain and .degrain file extension. To use a setup on an Autodesk SGI-based system, transfer the setup file over the network (using an FTP utility, for example), and copy it to the appropriate directory. In the UNIX hierarchy, the setup files are usually saved in the directories named "regrain" and "degrain" in the project folder. Because grain depends on variables such as film stock, lighting conditions, color, and resolution, it is advisable to change the Add/Remove Grain settings for each shot you need to process. 719