I’m having some problems understanding Lightmass, or atleast the results I’m getting. I’ve made a storage rack 3D model, layed out the lightmap UV myself, imported into UE4 and tried building the lighting at production level. The results are… not quite what I expected. There is certainly a reason for it, I’m just not sure what I’m actually looking for. This is where I could use some help.
First and foremost, this is my model seen from within the editor:
And finally, my Lightmass setting in World Settings.
I changed the level scale to 0.1 and bumped up the lighting smoothness to 2.
Results
With this model, the shown lightmap UV, the Lightmass settings, and a lightmap resolution of 1024 (I* tried lower, but nothing seems to change*), this is the results I’m getting.
The shadows on the floor looks good enough, but that’s another asset. Notice how the shadow from the top shelf gives til strange shadow on the bottom shelf. I can’t seem to figure out what is causing this, and any hints towards a solution i greatly appreciated. If you need further infomation, please let me know.
Sure more bounces (10) wouldn’t hurt but it should look good even with these settings! :S
…and you don’t have to go that high with the scale… I’d try to build it again with the defaults (1)s but 10 for each bounce…
Your sun/sky is tuned or kinda the default?
Usually when the shadow is this distorted it’s due to low res lightmaps… but 1024 should be enough for this mesh!
Okay, this I don’t understand. As soon as I turned the lightmap density view on, I knew what was happening. I don’t know why I didn’t do this earlier. However, looking at the details of my mesh, I am not overwriting the light map resolution, and it’s set to 1024. This I don’t understand
Detilium, when the lightmap resolution is not overridden by the details panel setting, as pictured, then it defaults to the mesh’s lightmap resolution which is set in the mesh editor. There’s a minimum for the mesh, and there’s the actual setting, both in the mesh editor. Make sure the minimum for the mesh is not higher than the actual lightmap resolution, or there’s going to be issues most likely…especially with a large disparity between the two. The curve shadow of the top shelf’s shape on the bottom shelf looks to be due to shadow sharpen filter in the directional light. I was having the same curved shadows for sharp corners and straight edges, and it was because I set the shadow sharpen filter to above 0. Anything above 0 begins to curve shadows. Not sure why, and I think it is a bug because sharpening shadows shouldn’t auto-curve their shape from straight edges / corners.
You don’t need 1024 lightmap resolution on such a simple mesh, and with the lightmass settings shown. 256 would probably be the highest you would need to get a nice result, whereas 512 is a bit too much. If it’s not happening on the other, similarly simple meshes, and those aren’t 1024/512 lightmap res, then set it lower. Otherwise, it could become a hitch or get artifacts from how incident and indirect lighting bounces off other objects that have low resolutions in their lightmaps. It would stand out considerably is what I’m getting at…
I understand that when I haven’t overridden the lightmap resolution, it default to the reslution defined in the mesh settings. The mesh resolution is set to 1024. I am aware that this is WAY to much, but this was just for testing purposes. I do intend to set the resolution lower, I was just getting desperate
On the topic of shadow sharpen filter, we’re talking about the property on the directional light correct? This is set to 0, as I haven’t touched this.
I’m still confused about why the resolution (as shown by the lightmap density view) doesn’t seem to be what I defined (my 1024). This is somewhat of a mystery for me, but I suppose this could be part of the culprit. I’ll have to investigate that.
That is strange. 1024 wouldn’t yield blue, I would think. Interesting that sharpen filter is 0. Not that it would be the only cause of curvy shadows as distance fields and cascaded shadow maps can cause it too. But that’s according to the docs for previous versions. It could be something else. Mismatched mesh and light source resolutions might do it, but why? It’s far-fetched.
Yes I do
