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During rendering, wherever 3Delight encounters a texture that is not already optimized, it will try to optimize it automatically. Optimized textures are stored at the same location and will have the same base name as the source texture. but with the added a .tdl extension added. This process will skip any texture that have the .tdl substring in the file name (e.g. texname.tdl.tif and texname.tif.tdl will be considered as optimized).
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