ScalarParameters rerouted into Material Function will not show up for a Material Instance

If you use the reroute nodes available in the Material Editor as of UE4.15, there seems to be a bug with Material Functions that causes scalar parameters to not be visible in child Material Instances.

Repro steps:

Create a new Material.

Add a ScalarParameter to this material.

Connect this ScalarParam into a Material Function, and then connect the Material Function into one of the final Material Attributes.

Add a Reroute Node between the ScalarParam and the Material Function’s input pin.

Create an instance of this Material.

Note that said ScalarParam will not show up under the parameters for that Material Instance.

If you remove the Reroute Node, the ScalarParam should show up for the Material Instance like normal.

Hi Wahrer,

I attempted to reproduce this but didn’t see an issue on my end. The Scalar Param shows up for me in the Material Instance.

Could you provide a small project that just contains the materials with the issue?

We haven’t heard back from you in a few days, so we are marking this post as resolved for tracking purposes. If you’re still experiencing this issue, please feel free to post back here with additional information to reopen the post.