# What materials are the Custom Alpha templates suitable for? What are the special parameters?

The only special parameter of this template is the "Opacity Map" parameter. But there is a slight difference with the "Opacity Map" in the Cloth material template. There is no semi-transparent effect here, the material is either **completely preserved or completely hollow**. 

Therefore, here it is recommended to use only black and white map to control the hollow effect. 

  * White is the material that is preserved, and black corresponds to the hollow position.

![image](https://docs-static.d5render.com/~/files/v0/b/gitbook-legacy-files/o/assets/-MjbN1iGmN_HBnj_fyU9/-Mkeq_gBgXvtoU8OUgdO/-Mker6UJPFSjcsgLKwHY/alph.gif)

In the range of 0~255, Opacity Map gray value greater than 157, the corresponding material will be retained, and gray value less than 156, the corresponding material will be hollowed out.