That’s interesting. Thanks! I’ll try to reproduce it in a new project. Maybe something else together with modulate acts up.
Just for clarity the way I tested was by applying the modulate material to a plane and then positioning the camera in front of it so it was covering the whole screen. It was an empty scene though, but I tried adding some Lit translucency (thin translucent and default lit) to the scene and the reflection cost was still basically flat with/without the modulate material.
Tested with both software and hardware raytracing, couldn’t really think of anything else it might be but if you come up with something else you want me to test I’ll give it a shot.
I’m on an nvidia gpu btw, 4070 super, in case it may be hardware/driver related.
interesting. modulate seems to be broken in my engine setup. the additive mode breaks when rendered with raytraced translucency.
i’d have to check some shaders to find where that composite happens, now.
Encountered this in the Nanite foliage sample, maybe a better view of the issue (or at least less seizure inducing). Definitely looks pretty gross.
yeh. that looks pretty bad. i guess they should preload some sort of data into the color buffer when they hit pixels that have no motion history. iirc there’s a bit for that. what data to throw in there? i dunno. something that has luminance. skylight color match., world grid or screen space neighbors to probe quickly. : )
@Krzysztof.N
BUG: I just tested the ray-traced refractions in Unreal Engine 5.7 preview. And Ray ray-traced refractions are still blocking GI inside glass objects.
well… i shoulda shared this earlier? been doing a bunch of experiments.
it’s not a bug. there is simply no GI data in the raytraced scene. it’s just polygons, light data and materials. if you use the right glass material you can get light into the bottle. left is the singular mesh. right is the split one with pills/cap and glass seperated. the latter, like the shelf i tested, has some issues. both have a double layer of refracton. this is still 5.6, btw. same result in 5.7pre.
and the view outside of the shelf. the glass plane is simple translucent since refraction on that would be wasted. you can see a hint of illumination but still no GI, since the data is not available in the raytraced scene which is inside the bottle. it’s just how raytracing works.
a cheat i would try, is to bake a static GI texture into the bottle. perhaps with a dim switch you can put into the per instance data for authoring the static light level or color.
Unreal Engine Developers might figure out something to overcome this limitation. A few years back, who knew we would have something like Megalights?
For the time being, instead of relying on baked texture, I can keep the refraction disabled.
Your top image also has dark shadows. which looks bad. And after disabling ray-traced refraction, I get better shadows instead of completely dark. So I think it’s better to keep ray-traced refraction disabled until devs figure out something.
you dunno how? okay. i may pick it up again, tomorrow. it’s not rocket science to get a bit of occlusion baked and make the shadows brighter with some shader design.
yes I know how to bake AO. But instead of a workaround, I would love to know the unreal engine’s developer take on this issue. I already sent the test project to developer
okay. you don’t want creative? it could be done a lil cheaper. but you insist on a developer reaction. like TI. the whole stigma. rant platform. i really don’t know why you need this done in reatime, anyway. it’s just some pill bottles in a shelf. will they move at any point in time? no choice to bake some static data?
i’m out of this loop, then, anyway. : )
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