When is it (not) ok to let brushes clip each other?

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kinggambit

L1: Registered
Oct 13, 2013
17
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I was wondering if there was a rule of thumb to follow for letting brushes clip.

I'd usually have to cut my brushes to all fit each other like a jigsaw, but I feel like it's just inefficient and leads to poor performance (i.e. a 10-sided room with just 1 floor brush vs multiple floor brushes fashioned to fit within the walls' dimensions).

I heard brushes clipping can cause bad lighting and weird visleafs.
 

LeSwordfish

semi-trained quasi-professional
aa
Aug 8, 2010
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Brushes overlapping CAN cause that sort of thing, however it's the exception rather than the rule. Generally you're safe to overlap, and you can start making things more complex if they cause problems.

The only time brushes overlapping is a bad idea is if you have two faces with different textures at the same place. This is called z-fighting and looks ugly since the textures flicker back and forth between two options.
 

Beetle

L9: Fashionable Member
Aug 17, 2008
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The only time brushes overlapping is a bad idea is if you have two faces with different textures at the same place. This is called z-fighting and looks ugly since the textures flicker back and forth between two options.

I thought it did that whether the same texture was being used on both faces or not.
 

A Boojum Snark

Toraipoddodezain Mazahabado
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Nov 2, 2007
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In general, there is nothing wrong with overlapping brushes. If everything looks ok, it is ok.

You should Aldo be careful not to have airpockets in solid, viscutting geometry
"air pockets" don't matter in that case. VBSP uses entities to determine what is the inside of a map (hence leaks), and if there is any enclosed space without an entity it is considered void and culled from the map. Leaving pockets in non-world geometry is the problem, since it won't count as enclosed and you will have extra faces rendered.

The only time brushes overlapping is a bad idea is if you have two faces with different textures at the same place. This is called z-fighting and looks ugly since the textures flicker back and forth between two options.
I thought it did that whether the same texture was being used on both faces or not.
If they are both world brushes (or part of the same entity), having the same texture (including alignment) should cause the faces to be merged and/or one will cull the other, however you look at it. I also want to say that two differently textured world brushes won't z-fight because one will cull the other, but I am not positive.
 

Beetle

L9: Fashionable Member
Aug 17, 2008
627
178
oh. well I've always just tried to perfectly align all word brushes and not care (unless it's simple) when it comes to entity brushes. I guess that's why I've only ever seen obvious overlapping of faces.
 

grazr

Old Man Mutant Ninja Turtle
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Mar 4, 2008
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Aligning world brushes can cut down on unnecessery vvis cutting of visleafs and reduce waterindices. But mostly it depends on how anal retentive you are about that as most of the time the actual impact on performance is negligable.
 

Beetle

L9: Fashionable Member
Aug 17, 2008
627
178
Aligning world brushes can cut down on unnecessary vvis cutting of visleafs and reduce waterindices. But mostly it depends on how anal retentive you are about that as most of the time the actual impact on performance is negligible.

I remember when I did mapping with TFC and it was crazy important. oh the good ol' days