Talk:Adding Water

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Flowing water?

Why is it that a water brush cannot vary in the Z direction at all?

Say, if I wanted to create a natural looking river or stream, it would be highly unlikely that the entire stream would be "flat." Don't get me wrong, the water in Source looks amazing... but it's all non-moving water. One would think that with the advanced physics this game is capable of, liquid would be something that could be mimicked, or is something like this too expensive for even today's juggernaut computers to handle with any sort of playability?

  • Moving water can be faked. I created a "rapids" type system by applying a water texture to a displacement. I then used the "paint geometry" to raise and lower certain areas of the water in the z axis. I then applied a scrolling wave material (much like the shorelines in MINERVA:Metastasis) as an info_overlay over certain parts of the displacement to give the appearance of water rushing over rocks. Finally i used several trigger_push entities to push the player down the river (i assumed they weren't able to swim back up rapids). creating a believable river that is calm, yet flowing, could be a challenge, but something like rapids is certainly doable. If you use some sprites or other particle effects to simulate spray, it could really come out quite convincing. --vecima 13:44, 8 Feb 2008 (EDT)


  • Water is exceptionally hard to physically simulate, both from a research perspective (working out how the hell it actually DOES move) and from a hardware perspective (actually simulating it in real-time). Water is still something the Pixar guys have trouble with, and they don't have the problem of having to render the screen 30 times a second. Still, I have to ask the question: What the hell is a PVS? --Graham 19:44, 8 Jul 2005 (PDT)
I added a definition page for PVS and made links to it in this document. --IanL 20:19, 8 Jul 2005 (PDT)


  • Question: If I wanted to make an area in a level have the effect of water (ability to swim up and down) without having any kind of water surface, how would I go about that? I am wondering because I recall an old Unreal-Tournament level where an area with water "rules" was used to make a sci-fi floating elevator-shaft thingy. Can one make an area with water "rules" in which it is impossible to die by drowning?
Don't give the player the suit. It limits many thing's like weapons, but you can't drown. --Welsh Mullet 19:33, 15 June 2010 (UTC)

Water Troubleshooting

I have a scene in which the water is rendered upside down. By this I mean from the surface I can see through my level to my skybox, when I submerge the water refracts. I have water in my 3d skybox, equal height. Compiling in hl2. --FViral 16:33, 9 Sep 2006 (PDT)

I ran into this issue too, i found that certain skyboxes can't render properly with certain water. An example of my work on a TF2 map, the world skybox was alpinestorm_01 and the water was well, the water didn't render AKA i saw through the map, so I changed the texture to something compatible with the skybox using the sawmill water, that seemed to fix my issue. Also, make sure you're using a env_cubemap entity and have your skyboxes sealed with no leaks. Somebody5000 10:02, 23 April 2012 (PDT)

Contact with world brushes

After reading http://www.student.ru.nl/rvanhoorn/optimization.php?chapter=notices I discovered that water brushes may not intersect with world brushes (such as skyboxes). I spent several hours fiddling with my map in Hammer before finding this. Could someone with a bit of knowledge on the subject add a warning and explanation in to this page.

I ran in to this problem when trying to create a shoreline in my map, which would only be visible when submerged in it, or when shooting at it. Unsigned comment added by Pepolez (talkcontribs) Always sign your posts with four tildes (~~~~)


I got problems whit that too, need i to make ALL the water to not contact world brushes? From Herover. [email protected]

Water Material Creation

Can we have some sort of water creation tutorial? I've had a look at the base code of water and the water shaders and material creation - hell, I've even checked out the waterfall material creation, and yet I can't seem to make too much sense of it.

Water Level Changes by Trigger

I was wondering if it is possible to vary the water level in-game due to a trigger? i.e. CP is captured therefore a trigger changes water level. I understand [womewhat] that within a PVS there can only be one water lefel. Ibelieve that means that you ant have two different bodies of water at different levels. So if im not mistaken we CAN change the water level of the same brush. The question then becomes: how do i simulate a change in water level? moving the whole brush up and down when triggered? or can a trigger transform brush dimensions? any input would be greatly appreciated--azar 05:12, 28 March 2009 (UTC)

  • You can make a changing water level by tying the water to a movable entity, but you definitely wouldn't be able to get the expensive water effects. There is a HL2 map (in the canals chapter, if I remember correctly) that uses this as part of a puzzle. I suggest you decompile that map and use it as a reference. I also recommend reading up on func_water_analog. Headprogrammingczar 13:55, 5 July 2009 (UTC)

Only one water level? SURE?

In this page it says that there can only be one water level in each PVS, but does this limitation exist in the 2009 engine? I ask this because I saw a video (http://www.youtube.com/watch?v=fQVvIV7oVJo) wich clearly shows 3,4 and more water levels being rendered at once. That water is obviously expensive because it reflects stuff around it (like the spotlight's beams). Take a look at that video so you can see it by yourself!--Mgs Blazer mgs 05:57, 18 September 2011 (PDT)

Well, TopHATTwaffle is clearly a sorcerer of the source engine, so that doesn't say much, but you never know, it might work, it might not work, but it doesn't matter anymore since source 2009 isn't available anymore, but the limitation might not be there in any source engine version since 2009. --Hawkfang42 (talk) 15:17, 27 May 2020 (UTC)

If you look closely, the water abruptly switches between the real-time reflections and the cheap cubemap reflections on each transition. AFAIK the limitation is still there. Rectus (talk) 18:45, 27 May 2020 (UTC)

And the camera positioning is very strategically done to make that less obvious. Loudslappingsounds (talk) 01:38, 28 May 2020 (UTC)