Topic: [Q4] what is Sky Caulk and how is it used?

[cuetip]

What is sky caulk and how is it supposed to be used?

[ratty redemption]

iirc you would use it on the skybox faces that aren't visible to the player, ie the outside of the skybox and in between the joins. i might be wrong though, but i'm sure kat or one of the other guys will correct me if need be.

[kat]

What Ratty said. Normal caulk can cause problems on brushes covered in sky shaders/textures so when you cut them up you use "sky" caulk instead of normal caulk on the unwanted sides. Same goes for "water" caulk, that does a similar thing - both are nodraw surfaces that are 'solid' to the engine.

[cuetip]

Hmm. Well I loaded up a Quake 4 SP map, airdefense1, and the entire sky and sky walls were all sky caulk. What I don't understand is how the skybox texture is painted on the sky if no skybox texture is selected for those sky brushes. I tested the sky caulk texture and it doesn't contain any kind of skybox texture, as I expected. So how is id making an actual skybox texture appear in the sky using only sky caulk? I hid the sky caulk texture to check if there was an actual skybox texture under it, but there wasn't. Any ideas?

[ratty redemption]

interesting and to clarify have you checked their sky shaders or just the textures?

[kat]

Zoom out of the grid view and you'll see a big box off to the left, that's a 'skybox' (it contains something that looks like a rocket). Skycaulk looks to have been used to 'seal' the main level off from the void (so the level doesn't leak) whilst allowing the skybox texture (which is a star field) to 'auto-project' around the rest of the map; you can't normally do that without causing a HoM (Hall of Mirrors) effect. Also check for 'projection' entities in that general area (they also used a 'projected' skyboxes in some levels iirc).

[cuetip]

The space field is for the opening cutscene. It's not seen when in the level. The other giant room with all the blue sky textures seems like where the skybox would go since there's a lot of effects like lightning and ambient ships zipping across the sky as seen when you first spawn in that caulked out area. I didn't find any references to an actual texture for the sky though. I don't understand how the skybox room is displayed in the actual level. Is it done by cameras?

[kat]

Yes, although I'm really stretching now as I don't quite remember how projected skyboxes work. Cameras are involved though iirc. Basically you set up a skybox with all the stuff you want going on in it, this is then 'projected' using a camera or 'skybox' entity onto your 'sky' brushes. I just can't remember the right mechanism to do that so you'll need to experiment...

Here we go.. try this
http://www.modwiki.net/wiki/How_to_add_a_sky

[cuetip]

Thanks kat. I'll experiment and report back.