Static Shadows slowing frame rate

I have a large architectural scene. I used a Blueprint construction script to instance 18 point lights as part of a chandelier. The lights are set to static. When i turn off “Casts Shadows” I’m running at 12ms a frame, but when i turn on “Casts Shadows” and turn off “Casts dynamic shadows” (leave on casts static shadows) and build the lighting the frame time jumps up to 19ms. Is this to be expected? Should static shadows affect frame draw time?

The 7 ms increase (with static shadows turned on) is just listed as an increase to “static opaque lightmapped” in the gpu profiler.


They should not. Are you sure they are not internally falling back to stationary or movable lights?

For example: the root of a blueprint is moveable by default, which means that any light added through the construction script will be forced to be moveable as it is impossible for a moveable parent to have static or stationary children.

Also remember that you can use the different viewmodes to debug these kind of issues. In this case the light complexity view should show no influence for the static lights, if they are visible in that view they are falling back to a more expensive type of light.

Static lights are fully baked to lightsmaps. No matter which settings they use performance is always same. These just don’t affect to runtime performance any way.

I had everything set to static, but looks like not turning off dynamic shadows in the root (even though there was no point light in the root) was causing the issue. Thanks!