User reported trying to use a Vector Parameter with a Custom Expression and the parameter was only registered as a Float3 and would give the X3017 error when compiling.

I confirmed this and tested the same node with a component mask set to RGBA and again the Material Editor threw a warning about not enough arguments from Parameter (float3) to mask.

Constant4 Vector works without error in both cases.

This is contradictory to documentation which says that "The VectorParameter expression is identical to the Constant4Vector"

Steps to Reproduce
  1. Open a Blank Project with No Starter Content
  2. Create a New Material
  3. Add a Vector Parameter
  4. From the Vector Parameter, add a Component Mask (RGBA)
  5. From the Component Mask, connect to Base Color

RESULTS: Error regarding arguments in Vector Parameter

EXPECTED: Vector Parameter to retain a 4 vector output and no errors generated.

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ComponentUE - Rendering
Affects Versions4.
Target Fix4.18
CreatedOct 9, 2015
ResolvedSep 19, 2017
UpdatedNov 16, 2020