I recently updated from 4.11 to 4.13 (so it may have started in 4.12) and I noticed that the birds_circling particle systems no longer function correctly. They are Epic assets, though I’m trying to remember which demo they came from. I’m guessing this also affected other particle systems.
The system spawns bird meshes that travel at a fixed radius and have a vertex shader to make the wings flap. The problem is that the birds all spawn in the same direction and no longer rotate along their flight path. This looks especially weird when the birds are flying sideways and their wings are alternating because the shader is supposed to move forward.
Here’s short video of the phenomenon. I enlarged the birds’ size to better show the effect.
thats… not good enough imho.
It should be fixed in 4.13 itself as its breaking a project soon to be released on steam, way prior to 4.14 being released.
Not to mention the time it will take to either edit the hundreds of particle effects or the time it will take to fix all the things that will break moving to 4.14 from 4.13.
The version that a fix is determined for is addressed by the developers. Unfortunately, I have no grounds to change the fix version or the severity of an issue. I’m sorry this issue is holding up a release but currently the only way to resolve it is via the workaround provided.
You can try the property matrix to change a setting on multiple assets (not sure if that will work) otherwise making a small edit to all of your particles is the only option until the fix is implemented.
After some testing I was able to reproduce this issue. It seems to be slightly different in the fact that it appears all the time and not after being cooked. If the 4.14 fix doesn’t address this issue I will put in a new bug report.
Have you tried downloading a 4.13 version of mountain landscapes and migrating the asset from there? That may be a viable workaround until this is addressed.