Maya's file texture node provides controls for blurring the texture (filter size and filter offset), but these controls behave differently when the texture is applied to a color channel versus a displacement map, so that extremely fine details can be captured.
So, though you can bring (for example) a photograph into Maya, use the filter size/offset controls to blur it out, and map it to the color of an object to see blurry texture on your object when you render, you won’t get the same result if you apply that blurred texture as a displacement map. Instead, the embossed image looks very crisp.
You have two options to blur the image suitably for displacement mapping:
- Increase the filter values, possibly into the hundreds before you begin to see blurring of the displacement map
- Make use of the Pre Filter control to blur the image file before it is used for rendering. This applies an image-space filter of a specified radius (in pixels) to the image before any operations are done on it.