What are Proxy Materials?
Proxy materials allow material assets tobe automatically switched based on the type of output image desired -- virtual photography (vray), 3D (webGL), or AR (Android [glTF] or Apple [UDSZ]).
How To Create Proxy Materials
A new proxy material may be created by selecting the option from the dropdown beside "Physical Material" on the "Add Asset" screen.
Any existing material may be converted into a proxy material.
Locate the desired material and enter the asset editor mode.
In the upper right, under properties, click "Convert to Proxy Material."
In the popup window, select "Convert."
A copy of the material will be created with the word proxy after the name. This new proxy material is created in the same folder location as the original material.
Any model assets previously assigned the original material will automatically be assigned the new proxy material upon creation.
The editor will automatically change to show the newly created proxy material. Under Properties, under Material, there will now be a sequence of dropdowns to select the desired material to be used for each type of experience.
When naming materials it is always good to include a label such as "proxy" to make them easier to locate in the dropdown menu.
Similarly, label uploaded materials for each of the proxy settings with their material type -- "vray", "webgl", etc.
Using Proxy Materials
After the proxy material is created, open the model asset. Select the appropriate node where the proxy material will be linked.
In the right-hand Properties sidebar, scroll down to "Material" and select the proxy material from the dropdown.
When a proxy material is modified, all connections to that material will be modified automatically.
Proxy Materials may have rules the same as any other material asset. For example, a rule may be created to select different finish materials for virutual photography and for AR.
In addition, logic may be used to passed information between proxy materials and standard materials, such that the proxy material acts as the parent of the standard material.