Are power 4 displacements safe to use?

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Mar 2, 2018
124
4
After reading this line in the valve developer commentary:
"Be cautious when using power 4 displacements, as physics colliding with them have been known to cause fatal errors."
I figured I should ask here whether it is safe to use power 4 displacements or are they game breaking in some sort of way? Also the situation does require the power 4 ones because I am working on a large map with a high level of detail needed.
 

Idolon

they/them
aa
Feb 7, 2008
2,105
6,106
Don't use them. Power 4 tends to cause crashes. Instead, chop your brush up into four and make each a power 3 displacement. It works the same, but doesn't have the same problems.
 
Mar 2, 2018
124
4
Don't use them. Power 4 tends to cause crashes. Instead, chop your brush up into four and make each a power 3 displacement. It works the same, but doesn't have the same problems.
I've actually done that already but the map is way too big, so I wasn't sure but after seeing this comment and reading more about the topic I guess that's a no. thanks for responding.
 

Crowbar

Spiritual preprocessor
aa
Dec 19, 2015
1,455
1,297
Power 4's are harmless with low enough density and lower powers are as dangerous with high enough. However, VBSP won't "compress terrain data" in a map that uses power 4 displacements, so yeah, just don't use them.
 

henke37

aa
Sep 23, 2011
2,075
515
Unless you are seriously starved for faces, just use multiple lower power displacements so that you get that compression.
 

ics

http://ics-base.net
aa
Jun 17, 2010
841
540
Power of 4 displacements cause a performance hit. Even if you manage to use them correctly, the map takes more memory to render and this in part can cause issues.
 

Harritron

L4: Comfortable Member
Feb 26, 2017
167
83
I recommend that you don’t use them at all unless it is in an area where nothing at all can touch it.

One of the maps on the imp a few weeks ago crashed everyone’s games because a Heavy’s ragdoll touched one of the power 4 displacements.
 

tyler

aa
Sep 11, 2013
5,102
4,621
The density is quite low, I've got a big arse map but everyone says you shouldn't use them so I guess I won't
This makes it sound like you're using one massive brush for a very large area of space (or a small number of brushes at any rate). Is that right? That is absolutely not what you want to do, if so.