Importing a FBX with several meshes takes long time to be imported in Unreal

Hi all,

Just one question because I don’t know if it is a bug or I’m missing something. I have a FBX with several meshes inside exported from 3DSmax. I try to import the FBX as Combine in Unreal and it doesn’t make anything, Unreal keeps thinking long time and I have to kill the application after one day trying to import the FBX. I don’t know why this happening from Unreal 4.17 and it also happens in Unreal 4.18.3. I’ve made the same setup with Unreal 4.14 or 4.15 before and I didn’t have this problem. If the FBX is not combined Unreal imports all meshes without any problem after a couple of minutes.

thanks :wink:


When you import something it does some processing to the objects so if it’s complex then it could take a while. You can improve the import speed by turning off some of the automatic options like Generate Collision and Generate Lightmap UV’s

It is actually better to bring in combined meshed that are pre-tessalted interaction groups. Meaning that if unreal has to figure out the triangles and the edge flow is not clean it attempts to smooth the mesh to get a working edge flow. I would use the actorx plug in to figure out where the issue with the mesh is. Looking for non-manifold geometry is another thing to try. Likely you have combined a mesh with a different number of edge loops with a mesh that has fewer edge loops. A good trick to see what the unreal engine does is to try to add edge flow one edge ring at at time and see where that lines goes. Most of unreal is a soft body, a rigid body, or a crate. That is from the old documentation, anything that can not have physics applied to it is a crate. They may have removed the old crate logic in 4.17.

Thanks both!. But curiously, I don’t have the same problem with an older unreal version using the same mesh I want to import. For the last version and the previous one, I tried to import a mesh, it was combined, and I had to kill the application after 1 day importing the mesh. Fortunately, I think I have where is the problem. If I uncheck “Build Adjancency Buffer”, unreal takes less than minute to import the mesh. As I said, It is not necessary to uncheck this option for older unreal version like 4.14 or 4.15 when importing the same mesh.


I have plugin code that automatically imports FBX with fixed settings and it’s an order of magnitude slower on 4.18 coming from 4.16. I actually noticed it building the engine from source before 4.18 was release but thought it must be something in my FBX file or my test code.

I have the same issue. It takes eternities to get the meshes in from FBX. I updated few days ago, and before it went relatively fast. The program itself gets completely unresponsive.