Black lines and boxes on static meshes

Hello. I tryed to locate this question in the old posts, but there are a thousands of topics. Sorry if my question was answered.

I am attaching a few images of my scene. The UVW lightmap maps are correct, I swear, every thing is in the correct way.
In the render appears a lot of black squares and lines, like if the lightmap UVW are incorrect, but every thing its ok. I tryed to change the static lighting level scale, the indirect lighting quality even to 15. And the black artifacts continuing apearing.
As well, near the picture frames on the wall, the door frames and roof, there ara a lot of noise that it is impossible to get out of the scene.

Please, I have now the scene almost complete, I want to start with the programing and interactivity, cinematics etc…But I can not continue with this issues, there let my scene no photorealistic.

Thanks a lot everyone can help me.

here, other captures…WTH is going wrong???
Walls lightmap resolution is 1024


This used to happen with older editions… 4.17 and older if I remember well… there were problems with lightmaps and calculation… they were pulled in and those black lines appeared…
If you don’t use the older editions: maybe the way you leave gaps between your islands are not correct or you’re not using properly snapped lightmaps!
Could you show the wall segment’s ligthmap please?

On the floor and the door…
The blocks you see is due to lightmaps again: those blocks/rectangles are the lightmap blocks… If you’d check the lightmap density view, you would see that they match these artefacts perfectly…
Where meshes overlap other meshes they will apear since they are made out of rectangles (lightmaps) and the overlapping mesh is circular… You can cut those areas (overlapping) on your lightmaps and pixel snap your lightmaps to get rid of those…

lightmaps of the wall, I tryed with pack UV with padding, tryed to expand the map that corresponding to the inner face of the wall.

Door lightmap mapping.

I know that the squares matching with the lightmap ress. But why appears?? Why this lines if the mapping are ok? I am ussing the 4.26 version. The blocks are everywhere, there must be something else…

IMO, nothing else!! What works for me, you can ignore it or look for other solutions…

It’s not just you drop “randomly” the uv islands on a map and leave huge gaps inbetween! If you want proper lightmaps (especially if you’re doing achviz!) you’ll have to be accurate!
Decide your lightmap resolution, get a checker map in that resolution and pixel snap those islands in your 3d app! /if they are not accurately aligned with the pixels, you’ll get inbetween lighting results! /both from the dark area a the lit area!
Most of your wall’s lightmap is unused /empty areas/!! Exclude the faces that are not visible! Scale up everything as much as you can /you can use non-uniform scaling too!!/ Leave gaps according to your lightmap resolution as low as you can /too much gap is causing errors too!! …also I wouldn’t place this many surfaces on one lightmap!
When an object totally overlaps an other surface (your door for example with the handle), what Unreal can do is visualize an inbetween result!! This is why I told you to cut those overlapping areas out of the lightmap! …the door has a very low lightmap resolution for all those tiny and not tiny bits… Just place a 256 checker map over your lightmap uv and you’ll see how much information those parts will get: very few!! …some of them maybe will get non, since Unreal won’t visualize less than a pixel island!

Ok Thanks a lot!! It looks you are in the correct way since the begining. I’ll try to change again the UV maps. I tryed to make that in 3D max and unreal with automatic unwrap, but there is the same result.
I’ll try what you explained to me and come back with the results.

Thanks a lot again, Makigirl.