Scene laggy until I finish looking around

I have a relatively simple first person scene.
When I run the packaged version the scene is very laggy while I look around the scene for the first time. After I looked all around the scene, everything is becoming smooth and good.

I have tried it with texture streaming off, but noticed no change.

Any idea what causes it and how to mend it?

We’d need lots more info but from what I’ve got my first instinct would be to check light UV’s if you got any custom objects.

Some more info. It is a small interior scene, low poly meshes and low resolution textures (max 1024)
It has static lighting. It runs on Android, ASTC, GLES 3.1 on a high end phone.

With your comment do you mean to check my lightmap UVs? How can I troubleshoot this?

I’ve done an experiment. I 've forced No Precomputed lighting in my scene and tested it again… Same behavior… As I look around the scene lags. When I complete a full look around, then everything runs smoothly from then on…

Activate “stat fps” and “stat UnitGraph”, look around at the scene and look at the values. Also a good thing would be to view the scene with shader complexity enabled. I guess it’s to many expensive materials, lighting or to much polys (I think it was “stat rhi”)

Well, shader complexity shows everything as green. My materials are pretty simple. My polycount on stat rhi average on 1 million… That is a lot I guess and I cant understand why it is that high. Most of my meshes are on the < 1000 triangles count and there are not too many meshes in the scene. For some higher poly meshes I have used the built in the engine Reduction to lower the polycount. Maybe I have missed a very high poly object…

Do you think that a scene average of 1.000.000 polys is too much for mobile?

Yes I would say definitly. Some time ago I Heard some recommendations from Epic for VR and IT was around 100.000 in total If I remember correctly. Maybe start grouping your meshes in the worldoutliner in Folder or layers and Beginn hiding Them to find which meshes are the Bad Boys. Im Not Sure If There is a console command for IT or If it’s available in the profiler. You can also Look around in wireframe Mode. Happy hunting :wink: