Poser 4 and previous versions supported gradient-based bump maps using the proprietary *.BUM file format. Poser supports the BUM format using the root node's Gradient_Bump attribute and the Poser 4 rendering engine. To use this attribute:

1. Connect an image map node to the Gradient_Bump attribute input.
2. Load the *.BUM file into the Image_Map node.
3. Open the Render Options window and select the Poser 4 rendering engine by checking the Poser 4 Renderer radio button.
4. Check the Ignore Shader Trees checkbox.

NOTE: The FireFly renderer does not support *.BUM files.