Collision Disappear When Reimporting SM

Hello,

When I reimport static mesh UE4 deletes the existing collision I set up myself with primitives or using Convex Decomposition. It doesn’t matter if Auto Generate Collision is on or off (but it was on when the model was imported first time). When it is off then every collision just disappear without generating the new one.

Hello Nox_A15,

From what you have described you are having an issue with losing your collision whenever you re import a Static Mesh into UE4.

I attempted to recreate the loss of collision inside of a test project.

These are the steps I took :

1.) Created a new project
2.) Created a cube inside of Maya
3.) Imported that object into the new project and made sure that Auto Generate Collision was turned on
4.) I added the box to my level
5.) I opened up the details of the mesh by double clicking it in the content browser. This was to make sure that I could see collision on my mesh.
6.) Played in editor. This was so that I could confirm that the collision was working.
7.) I then stopped the PIE session and went to the SM in the content browser.
8.) I right clicked the mesh and chose to reimport.
9.) I then built the level and played again.

I was not able to recreate the loss of collision that you are experiencing. If any of these steps are different from what you have done inside of your project then please let me know.

There are a few questions that I have for you

1.) Can you recreate this in another project or in the 4.9.4 preview?
2.) Does this happen on any other mesh inside of your project?
3.) If you would link me your DxDiag?

After you have determined if any of my steps differ from yours and tried the above mentioned troubleshoots then please let me know what you find out. I will continue to investigate this matter in the meantime.

Thank you,

Hello ,

Before step 8 you forgot to delete existing collision and set up your own (with primitives or using Convex Decomposition). Then if Auto Generate Collision is off before Reimport your collision will disappear. Sometimes the editor will even crash after that.

But I tested this on one of my models and with a new test box in 4.9 Preview 4 as you suggested and it looks like to be fixed there. I will let you know if anything changes in the final release. Sorry for not checking that out earlier.

Thank you for your time,

Adam

Hello Adam,

Not a problem. I’m glad this appears to be fixed in 4.9 Preview 4. If this problem does happen again, then please post again and I will address this issue again at that time.

Thank you very much for reporting this,

This popped up for me just now in 4.25

I imported a static mesh from Blender and it auto generated collision. As it didn’t fit quite well I deleted the collider and generated one with Auto Convex Collision which brought adequate results.

Once I hit Reimport Base Mesh the old collider pops up and the generated one is gone. Can get rather annoying when you are frequently reimporting due to UV changes or anything similar.