[POSSIBLE BUG] Lighting with morph target preview

Development Rendering
1

Allo allo allo.

Not sure if this is a bug, desired behavouir or something I’ve done myself but I’ll report it anyway to see if anyone can get it to reproduce. Due to my modelling style, everytime I reproduce this, I’m still getting it - so it might be my modelling style. But I’m pretty certain it’s an engine bug.

Bug: The preview light of the preview window of morph targets is affected by changing morph values. Moving a morph value from 0 - 1 moves the light down the X axis. Moving from -1 to 0 also moves the light up the X axis.

Steps to reproduce:
Make a skeletal mesh in a 3D program, add some morphs to it (Make sure they’re pretty!) , import it into the engine and change some of the morph target values. The light moves! How weird!

Reproduced in blank project.

Gif of the issue: https://i.gyazo.com/6f306e862c5dfd637680a64aa18ef217.gif

Can provide source file if need be.

Not a showstopper but doesn’t seem like intended behavouir.

2

Hi KITATUS,

That’s actually the normals and not the lighting. Can you send me your fbx file, by chance? You can PM me a download link on the forums if you’d like to keep it private.

3

I can indeed, you’ll have to hang tight though. Won’t be able to for a little while.

But, here’s the plot twist - There’s no normal maps created for the mesh. Surely if there’s 0 normals, normals shouldn’t be influenced?

4

Vertex Normals, not normal maps

5

Here you go, this has been straight exported from the engine so it might be weird. Let me know if that’s the case! https://we.tl/kZibZgFZ8w

6

Can you send the source FBX? Morph Targets are not exported from the editor.

7

This is indeed a good question, I’ll dig around for it and will post it when it’s found

8

Different Mesh but same issue (created it just for you ;p) - https://we.tl/10oUyjrNOH

9

Hey Kitatus,

I was able to repro this with some content that I created. It appears to be what is reported in UE-19861, which is a known, but ongoing bug.

I’m adding my mesh to the bug report though.

10

Woo! Glad I wasn’t going crazy. Cheers for dealing with the situation ! Great work as per usual :slight_smile: