Circular routes around visportals problem

[Fidcal]

Many of us have come across this problem where there is a route both right and left through and back around some visportals to a common place. Either route on its own would have closed visportals but the two in combination opens up visportals and processes an invisible area.

 

In the city area of my map this was really difficult but I eventually found if I totally sealed a tiny sewer then it solved the problem. It made no sense but I rebuilt the sewer to include an S shape loop with visportals and this solved the problem. It mean I went from 8-12fps up to 30-35fps in some views quite a long way away from the sewer.

 

Now in the mansion a similar problem not immediately obvious how to solve. In the image you can see one route to the left through the open green doorway then right and correctly stopped at the red visportal. Another visportal just beyond that also shows red. I would have expected that not to show but maybe not - anyway that is not the problem.

 

If you follow the other yellow arrow forwards and back around the visportals you can see they are all green and indeed, showtris reveals all the big area beyond those walls is being processed. Yet you can see that each route on its own would have closed visportals. Indeed, if I take a few steps forward through this first big visportal then those beyond round the corner do close correctly.

 

I think I'm gonna rebuild one route - probably the one on the left- with an extra back leg to see if that solves it. I might also consider some distance-controlled func_portals even though the distance is relatively close compared to the city where I've used them extensively.

 

Dunno if anyone else has found other ways to solve these.

 

[Mr Mike]

I'm not familiar enough with VP's to know how they interpret when they should be closed but is it possible that it is because you have 3 VP's all overlapping and visible through the first large portal? It's tricky to explain but, what happens if you delete the middle of the 3, so neither 2 left overlap?

 

The VP's seem to be positioned a little strangely anyway. Why is the first large VP as wide as the widest point of the corridor when geometry there appears to be thiner? A smaller VP size should help reduce the number of open VP's.

[Bikerdude]

If I could see the top down layout I would ge able to suggest more. But I dont suppose just useing a few FPs to close said portals would help, assuming the hallway layout is crapped enough that you can have low portal_distance values.

[Fidcal]

haha! Joke's on me. I changed the visportal to stone and still got the problem so I did an internal leak test and found a tiny crack in the wall!

 

I just jumped to the conclusion it was the circular route because everything fitted the profile. Let that be a lesson to me.

[demagogue]

Cracks in the wall have got me so many times that it's instinctively my first suspect. Guess that means I need to focus on building with fewer cracks...

 

Heaven forbid, the universe will come crashing down if a single photon makes its way from one zone to the next...

[grayman]

Internal leak was the first thing that came to mind, because a few of those green portals should have been red or not shown, which they became once you stepped out of the leaking area.

 

Glad to see you caught it.

 

I've found numerous pinhole leaks just from walking around and wondering why I was seeing portals I shouldn't be seeing, even red ones.

Edited July 15, 2010 by grayman

[Baddcog]

Well, I did this up before I read that you found a leak.

 

I'll post anyway because it might help some, maybe not)

 

 

Looks like you could make the portals smaller in these doorways, that would deffinately close things off earlier (note the orange line through a smaller portal.)

Ignore the pink, those were lines showing why I thought those portals would be open.

 

Fixing the leak should make that small red portal go away, the last green one go away and the second green to turn red.

 

Making that second blue portal smaller should close off one more (the small green one)

[Fidcal]

Thanks. This geometry and the visportals are placeholders. I've made this mansion like a lego with thick standard, moveable walls so I'm still pushing them into their final configuration. I'd just done the main stairs which are beyond that wall and doing a quick visportalling in the surrounding areas. So yes, those visportals will no doubt be fine tuned and reduced eventually.

 

I wished I'd known this stuff when I was making Thief FMs. Those of you who used Dromed know that portalling is automatic and I had no idea what it did. I thought it just compiled the editing data into game data. There were brushes called something like blockable brushes as I recall but I didn't know how to use them effectively. Automatic portallizing saves work but I suspect it is not so efficient as manual and of course I never built with breaking up the FM into portal sections in mind. I seem to recall talk of something called 'cells' and you could view them in game in Dromed which was fun but they didn't mean much to me.

[Baddcog]

Yeah, cells were just basically the airspace cut into cubes (or triangles) to fill in the space best for the surrounding geometry. Similar to looking at wireframes for how solid terrain gets split into tris in Doom.

That's why the official docs said it was better to cut a hole in a wall for a torch, than to add trim around a torch hole. Cutting a hole would make a cell inside the hole. Adding trim sticking out would dice the whole room up into a bunch of cells around that hole.

 

If you got too complex with all those cells created by solids ai could get stuck on cell corners (especially with sharp points of tris).

A blockable brush was just an airbrush that would force a square cell. So if you had areas with a bunch of small cells interescting where ai path you could place a blockable there and it simplified pathfinding.

 

Sometimes you could see cells in game due to ai paths. If an ai is walking down a hall, then starts to vear left and ends up scrapping down a wall, it's because he got stuck on an angled edge of a cell and followed it instead of walking through it straight.

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Auto portalizing is nice. Hammer does it to a degree. It splits the terrain up into leafs (like Dromed did with cells basically). But also like Radiant.

If you were in one leaf and could see into another everything in the second leaf is also rendered. But like Radiant it's still best to add portals to further optimize.

 

The one bad issue was that it worked in what I believe was clock-wise fashion. So it makes the splits as it goes around clockwise. If you have a mirrored map (deathmatch, both sides the same) then one side would be optimized one way, and the other side would be different. So you actually had to place portals to do manual splits in different places on both sides of the map to get the same leaf cuts. (done badly one side of map could be very optimized and the mirror copy on the other teams side could be laggy).