Editor rendering weird on tanslucent mats

Hey all,

I changed a default mat (M_LayoutMat) to translucent today, and now everything in the editor that’s using a mat instance of it seems to be freaking out. Certain parts are not being rendered. It seems the objects behind them are. and it’s not even the whole object, most of the time it’s cut off.

It does this in play mode as well.

Any ideas? Do I need to set some other properties in the mat editor?

Thanks all!

Hey AustinK -

Looking at your example map, I am going to make the assumption that you are using BSP Brushes (Geometry Brushes). There are some known rendering issues with these brushes. If you try to rebuild geometry in the level (under build lighting) the problem may go way but with the Translucent material there may be additional issues trying to render the Z depth of the scene. Try converting the BSP brush into a Static Mesh and see if the translucent setting on the material rendering correctly.

Thank You

Eric Ketchum

Hey Eric. That didn’t seem to work. ALL objects are now statics meshed. I re-built the level, and I still have the same issue. I’ve taken more SS’s for you.

The one that looks somewhat normal (except for the back stairs being cut off) is just me moving the camera forward till it popped to normal.

Thanks a bunch!

  • Austin

Hey AustinK -

Two quick Questions, one, what version of the engine are you using? Two, Can you double check the name of the Material you have changed. I am not seeing it in my Engine content at all.

Thank You

Eric Ketchum

Hey Eric,

I’m in 4.4.3 (downloading 4.5 right now), and as for the material, I forgot that I had migrated the materials folder from the ContentExamples project. You should be able to find it there. But, I also create a material that was simply a base color and had a scalar parameter for the opacity as another test. I still encountered the same issue. If things change on 4.5, I’ll let you know.

UPDATE: Upgrading to 4.5 didn’t work.

Hey AustinK -

Do you find that the rendering pops in and out based on your camera distance from a particular object?

Thank You

Eric Ketchum

Hey Eric,

Yeah, the distance will make them pop (closer is viewable, further and it will disappear. It’s not just distance though… but where it seems to be where the camera is looking? I’ve loaded some screen shots focusing on the blue platform (the one with a block above it and stairs leading up to said platform).

It’s pretty weird. I did read that UE4 has trouble with translucent mats so I’m going to just ignore using them for now. I can get plenty of work down without them.

But, if you still have more questions, want more Screenshots, or whatever else, just let me know.

  • Austin

Hey AustinK -

I believe that this is a Translucent Sort Issue but I want to test this more specifically so I can give you an appropriate fix for the issue. If you can can you upload a copy of the project for us to test? All you would need to do is zip up the Content and Config sub folders and the uproject file and upload that zip here, and if its too big feel free to link to a dropbox.

Thank You

Eric Kethcum

Hi! Any news on this issue? I’m trying to work around the same problem…

Hey AustinK -

After some additional testing, I can confirm that this is a translucent sorting issue. The engine renders translucency using the bounds of an object to determine placement of the translucent objects in the scene. So your floor which your character model is inside of will render behind because it doesn’t see the extents and it will pop back up when you move further back to reveal the edges of the bounds.

There is a way to fix this by setting the Translucent Sort Order in the Rendering Details of each mesh. The higher number will render on top of the lower numbers. This is universal though and will override all engine translucency rendering so use with care and caution.

Thank You

Eric Ketchum