The value of MaterialExpressionTwoSidedSign is flipped when calculating the Opacity Mask for Nanite meshes.
This seems to be a regression in 5.5.
1. Download the Licensee's test project and open (see addl info URL)
2. Open the map "/Game/Map"
3. Observe the two swords that use the same Material. One is Nanite, the other is not.
4. Observe the Material "/Game/M_TestSides". Expected behavior: The front-facing triangles are green and visible, while the back-facing triangles are red, but invisible. No red areas are expected to be visible.
5. Observe that on a Nanite mesh, only the red backside faces are visible.
6. Toggle "Disallow Nanite" on the Nanite sword
7. Observe that it becomes green.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-269216 in the post.
| 0 |
| Component | UE - Graphics Features - Nanite |
|---|---|
| Affects Versions | 5.5.4 |
| Target Fix | 5.6 |
| Created | Apr 10, 2025 |
|---|---|
| Updated | Apr 14, 2025 |