When you create a custom material, start with an existing material similar to the material you want to create. 
To customize a material, copy a material to a custom library and change the copy's properties:
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In a part document, right-click  Material  in the FeatureManager design tree and select Edit Material. in the FeatureManager design tree and select Edit Material.
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In the material tree, select the material on which to base the custom material. 
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Right-click and select Copy or press Ctrl + C to copy the material to your paste buffer.
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In the material tree, select a category in a custom library. You can use the Custom Materials library or a library you created.
 You can only add custom materials to categories within the Custom Materials library, not to the Custom Materials folder itself.  To create a new category, right-click Custom Materials and click New Category.     
- Right-click and select Paste or press Ctrl + V.
- Optionally, rename the material. Right-click the material and select Rename.
 
- Edit properties of the material, then click Save. 
- Optionally, click Apply to apply the new material to the current part.