vis brushes

solar · Post by **solar** » Tue Mar 25, 2003 1:19 am

Hi everyone, below is an image of part of my map in mohrad:

Area 1 is a large room which I've come to learn is known as a portal in editing terms. Connecting area 1 with area 2 is a short hallway and there is an open window that allows LOS from one portal to another. In both these areas are many detailed brushes and I'm getting some low FPS and high mtex in certain areas. From reading many posts, it is my theory that I need a couple VIS, or HINT brushes here. I have a line which I believe (with very little certainty) should draw the boundaries of my VIS brush, one at the top and one at the bottom. Is this correct and what other advice can the forum give me on placing these brushes?

Thanks

TheStorm · Post by **TheStorm** » Tue Mar 25, 2003 6:14 am

It's difficult to say because I don't know exactly how you have planed them from that picture but let's say this. The lower line that you draw must at least be aligned to the corner of that hallway (like the upper line). From this picture it looks as if the upper VIS brush won't help. At a certain angle from area 2 the engine will still see the new portal that are created by the upper VIS brush. You must probably have a different angle on it.

Post by **jv_map** » Tue Mar 25, 2003 7:04 am

The upper seems quite good I think. Must have some effect.

Note that a portal is not a large room but a 'window' from one vis leafnode to another.

wacko · Post by **wacko** » Tue Mar 25, 2003 7:10 am

If area 1 is cut into 3 portals by these 3 vis brushes, couldn't I draw a LOS from the portal over the upper vis brush through the window into area 2? So what would it be good for? Shouldn't the vis brush start at the lower edge of the window?

Post by **jv_map** » Tue Mar 25, 2003 7:12 am

You can still see parts of area 2 but not completely.

wacko · Post by **wacko** » Tue Mar 25, 2003 7:16 am

if area 2 is just one portal, everything is drawn. Or is this vis brush ment to cut through the whole map?

Post by **jv_map** » Tue Mar 25, 2003 7:20 am

A hint / vis brush is always structural, so it will divide area 2 in two leafnodes ('portals').

Ofcourse the brush should extent further than drawn here.

panTera · Post by **panTera** » Tue Mar 25, 2003 1:45 pm

one question, in the picture, where exactly are the trouble spots with the lowest fps?

What I would do is try to hide as much of area1 as possible when standing in aera2 and vice versa. But remember that hint brushes must completely seal off one area from another; drag them up to the sky or roof. Right now, the lower hint will be useless as Storm pointed out. The upper one should make some difference.
Let's say the player is standing in the middle of area1 (the now V-shaped part). Area2 will be drawn unless you put a hint horizontally though area2, just above the window (in topview) and just behind the line of sight. You could also extent the top hint so it goes through area2, but you'll hide less parts of area2.

"A hint / vis brush is always structural.."

Structural to the compiler then? As far as I know a structural brush can block the players view, a hint brush can not.

TheStorm · Post by **TheStorm** » Tue Mar 25, 2003 2:46 pm

panTera wrote: "A hint / vis brush is always structural.." Structural to the compiler then? As far as I know a structural brush can block the players view, a hint brush can not.

Yes it is structural to the compiler and will cause a split, but the hint brush will never block any views. The reason you use it is to make other portals "smaller" or of an certain "shape" so that the view between them are blocked by an ordinary structural brush that you allready have in the map and which didn't block the view before you did it. The price you pay is that you get more portals (higher VIS data).

Did that make any sense at all???

TheStorm · Post by **TheStorm** » Tue Mar 25, 2003 2:55 pm

Wacko wrote:If area 1 is cut into 3 portals by these 3 vis brushes, couldn't I draw a LOS from the portal over the upper vis brush through the window into area 2? So what would it be good for? Shouldn't the vis brush start at the lower edge of the window?

Yep! Area 2 would see the new upper portal created in area 1 (if area 2 is one portal), exactly as you said! And the lower one vill be seen too unless it's aligned to the wall.

panTera · Post by **panTera** » Tue Mar 25, 2003 3:06 pm

TheStrom wrote:...The reason you use it is to make other portals "smaller" or of an certain "shape" so that the view between them are blocked by an ordinary structural brush that you allready have in the map and which didn't block the view before you did it. The price you pay is that you get more portals (higher VIS data).

yes already knew that. Makes sense.

It makes BSP-splits just like any structural brush would, but I'd just like to keep the two apart. They may be structural to the compiler but are not just the same as an ordinary structural brush. I know that's not what jv said, but I think it's good to be aware of the difference. Some people still think that everything behind a hint brush won't be drawn, which of course is not the case.

solar · Post by **solar** » Tue Mar 25, 2003 4:31 pm

allright guys, I'm trying to hang with ya but being a noob it is difficult. This may be a lengthy post and I apologize but I think the more info you have the better you can help me. First of all, this map is based on the place I work, so as far as having things in mind when I started it to reduce certain problems was a bit difficult. Here is some more pics:

In picture one I have clarified where I believe the VIS brush should be. Sorry Storm about the first pic, I wasn't trying to be exact, just give a general idea. Shame on me. Rather than making two VIS brushes, shouldn't I just make one indicated in yellow? This would make AREA 2 not be drawn for anyone above or below the brush area, correct? The problem is anyone standing above the brush in that short hallway should still be able to see part of AREA 2 but the way I have the brush now, I don't think they would.

The second pic is the 3D view of the window to give you a better idea. Sorry about the poor quality, I'm on my system at work.

Below is a pic that gives you a larger view of my map:

The blue lines indicate structural walls.
It is my theory that the real problem lies in AREA 2 because if you look at the bottom of the pic, you see AREA 3 which also has an open window into AREA 2. Now AREA 1 has no LOS with AREA 3 and vice versa, but AREA 2 has LOS with both.

Pantera, to answer your question about the areas of low FPS, I have my spawn point in the middle of AREA 3, you can't see exactly where from my pic, but it's more to your right as you look at your screen. When I pivot towards AREA 1, I see the negative effect of low FPS (around low 30's) and high mtex (around high twenties). As I pivot towards AREA 2, it suffers moreso with FPS going down to the twenties and mtex up to mid thirties. This map has an outside area surrounding the entire inner area as well with glass windows on the north wall of AREA 1 that can see outside.

Some more info on the map, it is extremely large at 1,600,000 visdata. I have everything caulked and my skybox as tight as can be, but I have a lot of prefabs in it. My .map file size is 7.5 megs!! I have no intersecting brushes so everything seems to be fine. I just have it jampacked, I mean it has like 250 static models and I still need to put more in as well as assign my objectives. Once I put the prefabs in initially the .map file size went from about 3 megs to 5.5. I have been doing a fast complile to test it and I'm getting my FPS and mtex from that and I've read that those numbers are never accurate on a fast compile. So basically, maybe my problem is that it is just to jampacked. Comments??

TheStorm · Post by **TheStorm** » Tue Mar 25, 2003 5:25 pm

Post a picture where you have filtered out all detail brushes! If all the brushes I see in that picture are structural then I can understand why your VIS data are so high. The "yellow" vis brush won't help, I'll try and explain it later.....unless someone else beat me to it!!

TheStorm · Post by **TheStorm** » Tue Mar 25, 2003 6:18 pm

This is your picture modified with some "portals" (maybe not exactly how they will look in game depending on other brushes etc. but it could turn out like this. The blue lines will show you that there are a clear Line Of Sight and the VIS brush won't help you. Also I noticed that you actually have a func_rotatingdoor next to the window....ONLY structrual brushes block the view so even if you didn't have a window everything outside would be drawn.

TheStorm · Post by **TheStorm** » Tue Mar 25, 2003 6:33 pm

And this is how the portals could look if all those tiny brushes that I see in the map are structural brushes. This picture is PURE fake, I can't exactly tell how the splits will be done...but one thing is sure...even a 1x1x1 structural brush will create new portals. If those tiny brushes are structural then you know why your VIS data are so high.