As noted previously, every material in IMDS is ultimately comprised of Basic Substances, represented with the icon .
The Ingredients page of an MDS displays a tree structure which includes parent-child relationships. “Layers” are represented by indentations. Many sub-elements may visually separate items at the same layer. Although IMDS will permit different element types at the same layer, recommendations specify having only one element type per layer. The MDS types have a hierarchy which allows only certain children under a specific parent node:
• Components may have components, semi-components, and materials as children.
• Semi-Components may have other semi-components and materials as children.
• Materials may have other materials or basic substances as children.
• Basic substances may not have children.
The following figure displays a representative component tree structure.