Thats interesting, as I still didn´t manage to try this in a fresh project, its definitely possible there are some “skeletons” in our closet (pun intended).
The crash happens immediately when loading the map (or just the unreal project if its setup to start with the last opened map) including the blueprint actor, not just when opening any dropdown menu.
So…where is that dropdownmenu located, or how do I otherwise find any old destructible meshes?
…in the mean while, I can finally create a fresh project, I´m just quickly gonna test if I can reproduce the issue here as well. My Epic launcher wasn´t behaving recently…
Yeah, unfortunately I was able to reproduce this in a fresh project.
Just starter content and raytracing enabled, imported the basic mixamo y-bot, setup lead/follow in the blueprint. Checked pathracin…uh, its working, exciting!
Closed editor, restart project, crash.
Tried every possible combination of raytracing off/support lumen hardware raytracing (not that many), kept crashing.
I thought I was onto something, when I first disabled and then deleted the lead pose component from the blueprint and it kept crashing, when I reenabled raytracing through the defaultengine.ini.
But I think it just needed to recache something, after removing the blueprint from the level and then readded it (without lead pose component), it worked when raytracing was enabled.
So, unless those destructible meshes are in the starter content, I think its still confirmed that its only crashing with hardware raytracing and lead pose component enabled anywhere…
Ok, did some more testing and now it gets interesting…I got it working without crashing, but it doesn´t make sense to me:
Tried the same on my actual project…no dice. Still crashed.
I´m doing some more testing now, as I also disabled “support raytracing” in the lead skeletal meshs details panel and I also need to add a different lead skeletal mesh in my main projects blueprint, as I´m actually also using the skeletal mesh I use as lead pose skeletal mesh there for rendering.
So i´m now trying to replicate as best as I can what worked in the fresh project, just need to retrace my steps…
Welp. Its still compiling 15 minutes later…but I think its actually a good WTF moment, because if I can fix it in a fresh project, I should be able to fix it in my project too, with just a ton more troubleshooting…
Not sure what was going on here, I force closed unreal and then finished the setup…and I´m pretty happy right now, because I think I fixed it for me!!
Please let me know if this also works for you and if it does mark it as solution!
[EDIT: GOSHDARNIT. Too soon. Hit PIE and it crashed…
Still IS an improvement, as it means I can now at least have path tracing in my project, as long as I don´t use that blueprint. I hope.
I´ll try again soon…]
Alrighty, think I have a workaround for our project for now.
I added a branching in my animation setup, that allows me to simply set the animation instance on all skeletal meshes, instead of using lead pose. So, since its not crashing right away, but only once I hit PIE, i can use a boolean check to disable the lead pose, if I need raytracing WITH the blueprint. In maps without the blueprint it should work anyways.
Did anybody check the 5.4.3?
Wow. It definitely sounds like our crashes are coming from different places. This is crazy.
There’s gotta be an answer as to why Lead Pose Component would trigger this. All that does is get them following the same animation.
Yes, still happens with 5.4.3
Thanks for the idea! I digged the documentation a little bit and found the Skeletal Mesh Merge Working with Modular Characters in Unreal Engine | Unreal Engine 5.3 Documentation | Epic Developer Community
I even got better performance and now crashes 
Hm, yeah, unfortunately I don´t think that makes sense for our project.
As its a human anatomy model, there are literally hundreds of skeletal meshes that would need to be merged, not to speak of the nightmare of having to create the workarounds for all their unique morph targets etc…
But maybe “copy pose” would be another workaround for us, I won´t have time to look into that any time soon though, so if anyone has any luck with that s using “lead pose component”, please let me know!
Well, as with all optimizations…they come at a cost.
What I am guessing is that they might have changed something preparing for nanite skeletal meshes, which supposedly might already come with Unreal 5.5.
My hopes are that maybe by then they also got this fixed and I´ll have my workaround with the switch until then…
Also, on a side note…
I realized NOW that there is a “character blueprint actor” class, while our blueprint uses the standard “Blueprint actor” class.
Which made sense at the time, as I was planning to add other stuff like the background, lights and some empty actors to control size of all skeletal meshes etc.
But it may lead to other unexpected issues here as well and it DOES make some stuff harder.
Like: I can´t just select an animation and move it around in the sequencer trackm, unless I use the lead pose, where I can use the lead characters animation track.
But once again…no time to figure out if using the other class would be feasible now…
Bumping this thread because it’s a persistent issue and I haven’t found a bug tracker in the database covering this issue. This is a pretty major problem for any user of Metahumans in Unreal 5.4 (that’s a whole lotta people!)
Yeah, my bug submission failed for some reason, first time actually trying to properly report a bug, since the problem is persisting and really annoying to deal with and with every hot fix my hopes are getting smashed about the devs actually catching it.
I am still hoping they are working hard on nanite for skinned meshes and that problem is involved in that somehow, so its gonna be in 5.5 at least…
I found a fix! I ticked two options in Leader Pose Component and it worked!
I don’t know which does it, havnt tested it. But I can finally render our character.
Pretty sure I tried this.
You sure its working with “support raytracing” enabled in the project settings?
Also…I´ve been working on getting a modular control rig going now, but apparent, I was falsly assuming this would allow me to animate a bunch of meshes referencing the same skeleton with just one control rig in sequencer, without using the lead pose component.
But I just checked in the metahuman blueprint and it still uses the lead pose component.
When you drag it into sequencer, it automatically creates the control rig, but I guess its just doing that because it creates a track for the lead pose object. I´ll have to dig a bit deeper on this, so let me know if anyone knows a solution for that…
bump, anyone have a solution that doesn’t require disabling RT and skin cache?
Haven´t found one yet, lets keep bumping it…
