Description

It appears that the Vertex Normals from Ribbon Particles are opposite of what is expected via the Default Particle System given both systems share the same alignment (Facing Camera)

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Steps to Reproduce

*Quick Repro - Open the Attached Project and PIE, Press 1,2,3,4 to toggle between the cardinal camera positions. 5 will return to Player Camera*

Material Setup

  1. Create a New Translucent Unlit Material
  2. Assign VertexNormalWS to Emissive Color
  3. Assign a Constant 1 (value 1) to Opacity
  4. Save Material

Particle Setup (Ribbon)

  1. Create a New Particle System
  2. In the Required Module, assign the previously made material
  3. Also in the Required Module, assign Alignment to Camera Facing
  4. Assign a Ribbon Module to the emitter
  5. Disable or Delete the Int. Velocity Module
  6. Save Particle System

Particle Setup (Sprite- Default System)

  1. Create a New Particle System
  2. In the Required Module, assign the previously made material
  3. Also in the Required Module, assign Alignment to Camera Facing
  4. Save the Particle System

Blueprint Setup

  1. Create a New Actor Blueprint
  2. Add the Ribbon Particle created previously as a component
  3. Add a Interp Movement Component
  4. Assign a simple ping pong movement from (0,0,0) to (0,0,500) in the Interp Movement Component
  5. Compile and Save Blueprint

Level Setup

  1. Add the Default Particle System created previous to the map at (0,300,100)
  2. Add the Ribbon Blueprint created previously to the exact same coordinates (0,300,100)
    #PIE

RESULTS: The Vertex Normal of the Default Particle and the Ribbon is opposite

EXPECTED: Vertex Normal should be the same based on same camera alignment

Have Comments or More Details?

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Won't Fix
ComponentUE - Graphics Features
Affects Versions4.9.2
CreatedOct 13, 2015
ResolvedOct 30, 2018
UpdatedMar 26, 2020