What is Brush and Paper Textures in PaintTool SAI?īrush and Paper Textures allow you to create a multitude of unique effects in your drawing. Always use caution when downloading files from an unknown source.bmp files into the brushtex and papertex folders in your PaintTool SAI files directory. DeviantArt is a website and community with many PaintTool SAI resources. You can download custom brush and paper textures for PaintTool SAI online.