Only the first 128 instances of an instanced static mesh have collision when spawned in a blueprint

Collision is correctly set on the cube mesh. Attempt to do the same loop with the cube static mesh, do you see the collision error or warnings occur for you?

I found why it does work for you: If I use the HillTree from the kite demo with default collision, I don’t get the Warning. But if I add some more collision shapes (I just duplicated the default one 2 times) then I get the warning! So you need to have more than one collision shape in the mesh.

I would also recommend to do the AddInstance once per tick and not all at once in the contruction script, because if you do it once per tick you also get the warning once per tick, it’s spamming the whole output log.

I’ve had this issue before with a single collision mesh, I’ll test it again in the latest build and if I can repro it again I’ll upload the project.

Hi everyone,

I received warnings on objects with multiple collisions as John reported, however the collision itself still worked as intended. I have passed on the information of multiple collisions causing errors with instanced meshes and it is currently under assessment to see if it is a bug or if the error message is intended but not clear as to why the error is occurring, however the primary bug reported in this thread seems to be working as intended now.

The warnings are still in 4.8. I have not checked whether anything does not work, but the warnings are spamming the whole output log which is really ugly.

Hi everyone,

I’ve entered a bug report, UE-17589, to be assessed by the development staff for the log spam. Having said that, most likely this error message is intended functionality and the reason it is spammed is because it produces one error per instance. I don’t have enough information to say whether or not it is actually a bug with the meshes or if the bug is because the error is unclear.

Thank you . I’d like to get some clarification on what causes the log spam if it is indeed intended functionality because if there is some underlying thing that we are doing improperly in regards to spawning instances it would be good to know that.

Thank you again.

Hi, has this been fixed in a recent UE4 version? I’m still on 4.7.6 and have this issue. The warnings only appear with Instanced Static Meshes that have a Static Mesh set that has multiple collision parts. I didn’t count, but I’d say anything above 30 instances added to that ISM cause this. Collisions indeed don’t work when the warnings occur. As soon as I remove all but 1 collision parts from the Static Mesh that the ISM uses, the warnings (and collision problem) is gone.

My workaround would be to create separate ISMs for collision with one collision part per ISM, but that’s really ugly.

Hi anteevy,

Unfortunately, our resources are currently dedicated elsewhere. I do not have a timeframe of when a fix will be made available.

Too bad, but thanks for the quick reply.

Maybe you have some idea for a better workaround than the one I described? I’m importing a tilemap and the main problem lies with the corner tiles:

They require two convex collision parts because the corner can’t be covered with only one (would be too inaccurate) and if I understand concave collision parts are not supported, right? I also have tiles with 3 and 4 collision parts.

Just tossing my hat in the ring here to say I’d really like to see this fixed. Epic’s devoted a lot of resources to showing that UE4 can be used in large open world games, and this is a pretty nasty bug for anyone who’s using the engine for larger scenes.

I agree. The bug was reported in October 2014, and now we almost have 2016. It should really be fixed.

It doesn’t make much sense, because really, what good are instances if they break after only 128 of 'em? This isn’t some edge case, it’s fundamental to the usefulness of instances.