After updating to 4.14.3 (from 4.13.2) apex cloth causes crashes or doesn't display correctly

Hi everyone.

I need some help, please. Here is my story.

I have been making flags that react realistically to wind. I built the meshes in Blender (I was using 2.77a), I created the apex files using the APEX Clothing Tool 1.3 and then imported everything into UE 4.13.2. All of my flags worked perfectly, as far as I could tell.

I upgraded the Unreal Engine to 4.14.3, but then it started crashing every time I tried to load a map with the flags in them. I started testing the flags, one by one, and realized that three flags were causing the crashes. When I tried placing the flags the engine would crash. I tried re-importing the meshes, but this caused a crash as well. I deleted them and was then able to import the meshes. Unfortunately, when I imported the .APX files and tried to apply them, UE crashed again. So I was able to import the APX files, but applying them caused the crash.

Redoing the .APX files in the clothing tool did not fix the problem, it still crashes when trying to apply them, so I figured the problem was with the mesh. I edited a mesh that was working, made the .APX file and imported everything into UE4. It crashed again.

I decided to build a very basic flag to see whether I could get that to work. This time Unreal didn’t crash, but now the cloth was mangled into the “pole” area and would not display correctly. Multiple attempts and flags saw all of them mangled in this way.


Importing the same mesh and .APX file into UE4.13.2 works perfectly.


Updating Blender to 2.78a didn’t fix the problem.

I then opened one of the original flags that did work in 4.14.3, removed its .APX file and imported it again, just to see what would happen. It was mangled as well.


Is there some APEX related setting that was added in 4.14.3 that I’m missing that is causing this? Any help would be greatly appreciated.


Well, in case someone has the same problem, I seem to have found a way of getting cloth to work.

Firstly, I had to completely reinstall Unreal 4.14.3. I had to do this, because it started crashing whenever I tried to apply a .apx file to any mesh. I assume multiple crashes must have corrupted some files. I tried verifying it first, but that did not work.

The big change is that when you use the cloth tool you have to export the file as a .apb file. (I read it on some forum, I didn’t figure it out myself.) This seemed to do the trick.

The three meshes that caused the original crashes still refuse to work and cause crashes with .apb files as well. I have to completely rebuild the meshes, but at least cloth is working again.