Selecting Material Params of Different Types Causes Crash

Development Rendering
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1

There is a fairly unique repro case for this, but here goes:

  1. Create a new Material and add a new Vector Parameter. Give it a name and set the colour to something, and hook it up in the graph.
  2. Create a Scalar Parameter, give it a name and also hook it up somewhere in the graph. It MAY need to be in the same node chain as the Vector Parameter.
  3. Duplicates the Vector Parameter and hook it up in the chain, then change the colour but NOT the name.
  4. Try to Ctrl+Click on the Scalar Parameter and the Vector Parameter and you should crash in:

PropertyHandleImpl.cpp - Line 1793

This also seems to occur if you rename the duplicated Vector Parameter. At first I thought it was due to names, but it could be that the editor no longer allows you to select multiple parameters of different types. I do this quite often to group lots of related Parameters at once, regardless of type.

2

Note, you should select the Scalar Parameter first! Doing it the other way around seems to work as intended.

Further information, the crash call stack appears to be because ‘Value’ is set to ‘Empty’ (according to the watch window in VS).

Previously called from MaterialEditorDetailCustomization.cpp - Line 181

3

Hello -

Thank you for the report, I have entered the issue as UE-20401. As we continue to investigate a solution to this issue I will keep you informed here.

Thank You Again

Eric Ketchum