Why do my polyobjects ALWAYS bleed through walls?

why is it that my sliding doors ALWAYS do this on one side or both sides? it really sucks, and it's just so sad to see after I already put so much effort into the level that it is falling apart at the seams... if I can't figure it out, I have some other cool door ideas, but still, I want a few sliding doors at least.

You have an open area for them to slide into, right?

Of course... now my question is, can a polyobjects walls slide along the fixed walls? i mean, they would virtually be in the same linedef once the polyobject was in it's "slid back" position... but even that isn't working because, i gave one of my doors more then enough room on all sides, and it still bled through... then i use Zennode and it's still all jacked up.. I must be doing something wrong... might it have to do with the sector height that the polyobject is located in? (The initial, hidden sector).. or maybe even the sector height of where the polyobject is anchored to... hmm.. any ideas?

This is an known difficulty with polyobjects.

Unfortunately, there is no one solution. Offsetting the door jambs by a unit or 2 sometimes does it. Putting "junk" in the form of extra sectors and lines in the void area may also help. Just look at Hexen map01 (if you have it). Even that has some junk in there, presumably for the same reason.

Some node builders are apparently better, or at least different at handling this than others, but unfortunately it usually comes down to trial and error.

Rick Clark's tutorials on the zdoom site (on the tutorials button) cover this problem

specifically you want

http://zdoom.notgod.com/zdkb/polybld.html

I've had endless problems with polyobjects, starting with my Temple of the Ancients level set, and continuing into The Darkest Hour. In the end I decided to use few, if any, polyobjects. (In DH, you may notice that there are polyobjects only on Maps 01 and 03 -- the sliding gates. These were my early maps in the set, and the sliding gates gave me so much trouble that I decided not to use POs any more in the set.)

From people who've responded to the same question about texture bleeding, there are a couple of possible solutions (neither of which is guaranteed to work). First, as Nigel suggested, offset the door jambs by one or two pixels. You must offset them INWARDS. With Temple, I kept trying to offset them outwards, and the problem was never solved. Then I tried them inwards, and Voila! no more texture bleeding.

Another option (and it may be too late in your case), is to build your polyobjects last. Complete the entire map, then insert your polyobjects and associated sectors in one shot. Apparently, the texture bleeding problem is caused by improper node building. Thus, a sliding door will look fine when it's first built, but will have the problem after youve added sectors to your map.

Good luck, and in future perhaps you'll abandon polyobjects like I have :D

Another option (and it may be too late in your case), is to build your polyobjects last. Complete the entire map, then insert your polyobjects and associated sectors in one shot.

I suppose that was suggested by Rick Clark to keep one from wasting time? Otherwise, it makes no difference. Polyobject problems are caused 100% by subsector splitting and where the objects are placed.

Here's factual guidelines that make them work more often than not:

Use vertical and horizontal lines around the polyobjects. Having angled areas is more likely than not, to give one grief. So building a "box" area make the subsectors splitting less likely.

Then if one has trouble, doing "odd" things can all of a sudden make them work - only because the nodes shift just enough:) On a large level it's unlikely that the 2 unit shift will fix much if it's done "last".

As Nigel notes, drawing "odd stuff" on the map fixes things because it shifts the node split around. Hexen MAP01 is a good example - see the group sliding doors and the junk below them:)

IOW, the sequence and placement of the polyobject has an influence and so does the stuff around it. The sooner the node builder reaches that area, the better of on is likely to be, since it won't compete with other "splits". Experiment by adding "junk" that has nothing to do with the level.

Not that it will "fix" all polyobjects, but DeePBSP does give polyobject sectors preferential treatment. It can make most Hexen levels work without the workarounds:) However,sectors should be unique and not shared with other linedefs for this to work best.

And last, if you use the DeePsea node viewer and focus on the poly area, you can indirectly see what is causing the subsectors!