[bug] duplicateing mesh on map with ALT+mouse drag causes smoothing group to be removed

build 1808360

I noticed that using the default map with the cube and sphere and what ever the other thing is a torous?

if you ALT+mouse drag these assets the smoothing groups will disappear on the newly created ones. I also tested on one of my own created assets and found the same things happen to it, the only way to resolve the issue is to build lighting. the effect can be seen best on white and lowish poly objects from what i could see, but its really noticeable on the default meshes.

this likely happens in all cases regardless of which map you are using.

I can find no evidence of “smoothing groups” disappearing when duplicating a mesh. Smoothing groups aren’t used as part of the lighting calculation at runtime. They are only used at import time for the purpose of generating normals. What is happening is that the static lighting is invalidated as soon as you move a mesh causing it to switch to dynamic lighting for all objects with invalidated lighting (so you can see them). When you rebuild lighting it is rebuilding the static lighting for the new object.

Hi, just to make sure you are 100% sure about this
ftp://ftp.epicgames.com/FTP_Dropbox/Linkinworm/smoothing.png possibly requires you to login, but you can clearly see the duplicated object is now not smooth at all, this happens with any asset i use even my own ones, if your comment is still valid please close this topic, but im sure in UDK this didn’t happen.

The screenshot link doesnt work. Can you double check the link? I would love to see what you are seeing.

Hi Matt, sorry for the long reply, i never got an email for the response for this, that link wont work directly as far as im aware, and i cant link HTTPS links for the FTP, you need to go into the FTP your self, find my folder labeled

linkinworm then check the smoothing.png image from there, sorry for any inconvenience,iv attached an image of it, not sure if its resized to see the detail. hopefully it wont be too small.

Hi Marc,

You are correct that the faces of a duplicated mesh appear unsmooth, but as you say, this is only before lighting is built. In fact, you will notice that it is the same if you add a new instance of the sphere (Basic_Asset3) to the level. And, as Matt said, the same thing occurs even if you move the original mesh.

This is not the loss of smoothing groups, just a temporary condition of dynamic lighting until the lighting is rebuilt.

I hope that clear things up!