fixing the weird shadow

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Asd417

Sample Text
aa
Mar 20, 2016
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1,031
This is the ingame view
C4yugtR.jpg

You can identify the unnatural shadow

This is the hammer view
tB5xXwP.png

This is with func_detail marked
lSUXnGK.png

These screenshots show how these func_details are separated
ygrczMo.png

1PuiNrm.png

Lightmap grid is fine

How do I fix this shadow?
EDIT: no leaks found
 
Mar 23, 2013
1,013
347
Having brushes inside a skybox brush causes them to have shadows most of the time because despite the skybox brush emiting the light, it doesn't let any light through.
 

Asd417

Sample Text
aa
Mar 20, 2016
1,451
1,031
dustbowl_example1b.jpg

edit: Also, the weird shadow also appears on func_detail that is not touching the skybox brush. How about that shadow?
 

YM

LVL100 YM
aa
Dec 5, 2007
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6,056
I don't know why Source does weird things to brushes intersecting skybox brushes, or how to stop it but....

Thoughts:
  • It's entirely possible that a displacement face might not suffer the same issue, and since sheet metal on a roof is often made from displacements, that might be a good solution here.
  • It could be caused by lower than max compile settings. If there are fewer bounces, or rays fired that could easily cause something screwy. Try doing a compile with -final if you haven't already
  • That's a rooftop, it won't be seen much and by the looks of how they should be lit and shadowed, the faces should be fairly even. You could mask the issue by dropping the lightmap size to 64, or even down to 256+ to smooth out the entire face to just one or two luxels
And for the nearer roof, these both look like smoothing errors so:
  • Use hammer's smoothing groups to manually separate these faces
  • Change -smooth in vrad to a lower value, the default is 45 and any two faces with an adjoining angle below that will be automatically smoothed
  • Change the lightmap scale on one of the faces to be different from the other, this will prevent them from being smoothed
  • Make the angle steeper or hide the error with another brush
  • For the near, thin, roof it looks like it's smoothing with the face touching the wall as well as the other side of the roof, simply nodraw that face