Abstract: Conventional transfer function for volume rendering of finite element data is defined in
3-dimension field, while there are some 4-dimension data. In order to render them, a transfer function
model in 4-dimension field is put forward. The model combines the characteristic of finite element
data that the maximal data is more significant and the capability for filtering spatial data of volume
rendering. It extends the forth dimension to construct time-series volume rendering and multiple
volume rendering, so it enhances the flexibility of display for finite element data.

Key words: transfer function, 4-dimension field, volume rendering, finite element data