Hello,
i have a huge problem with lightmapping.
I’m tring to lightmap some houses, but the shadows i get are wrong.
On a wall i have many poligons. The lightmapper apply shadows near every line pf the poligons like in the pictures attached.
Can anyone help me? Is it a bug?
Thank you
How is the geometry? Are the edges detached? Are there polys inside the wall?
What uvs are you using? Automatically made or are you using your own?
What are the smoothing groups (Normals and Tangents) settings?
that polys are the wall (sorry, i don’t know if i understood the question, i can upload the fbx if you want).
generated: hardangle(88), packmargin(4), angle error(8), area error(15)
normals: import; tangents: calculate; (split tangents)
is it something wrong?
Either your mesh edges or uv edges aren’t welded together.
probably the uvs. But how can weld them if the uv are generated automatically?
i’m tring to manipulate the vars of import and of beast but i have not good results
this is the fbx file
If it’s possible, upload the fbx I would like to have a look.
EDIT: OK so you just did, I’ll check it.
If you don’t want to work on the model, just try to increase the packmargin. Those are bleeds of colour from nearby components.
The strange thing is that it is happening on a flat surface… looks like they are separated faces where it would be much more “right” (in a common workflow procedure) to make them contiguous as a single building face.
i generate that models via script. The reason i can’t work on the model is that there will be about 800 different models. So i have to find another solution. I tried with packmargin, but i saw that it decreased the resolution, is it possible or i saw wrong?
this is with packmargin at 30. But there are still too many problems. Like the shadow under the gazebo etc.
You can:
Increase the lightmap resolution.
Increase the pack margin. A combination of these two should give good results. Like resolution 8-10 and pack margin 10, or more. (experiment).
Make your own UVs where these surfaces are continuous.
Rebuild the geometry so that the polys are continuous (they kinda are, they share some vertices, but not all).
And oh yeah, make sure lightmap is uncompressed and see if that helps. (Lightmapping → Maps → Untick compressed) That last image looks like it suffers more from compression than anything else.
Thank you for your answer AcidArrow
ok i’ll try
i’ll try with 15
i can’t for the reason i wrote in the previous post
as point 3
EDIT: i have to see what happen in the exportation of the model (i’m using cityengine)
what happens on mobile platform if i uncheck it? Probably it will slow down. But the compression seems to be the 80% of the problem 
this is with resolution at 80 (the previous was 12) and compression on.
But it generates too many lightmaps (1mb in vram).
Anyway if you look more the picture there are anyway little lines on the poly line. Not as big as the previous.
I’ll try other tweaks…
Well… If you textured the walls, with for example some noisy plaster-ish texture, the artifacts will be hidden
