It can be challenging to represent instructional materials such as diagrams, models, and graphs in a tactile manner that clearly conveys specific criteria. The effective use of textures incorporates nuances around contrast, height and orientation to provide it's own tactile vocabulary. Use these guidelines and resources to understand how people read tactile diagrams and essential criteria for creating effective diagrams. 

A woman feeling a tactile diagram of an eye.Tactile Diagram Resources:

Design Principles for Tactile Graphics
Understanding Tactile Graphics
Guide to Making a Tactile Diagram
Creating Tactile Graphics from Teaching Students with Visual Impairments website