I am having trouble with my Ogres.

Going upstairs he is OK but when he returns, he seems to get stuck and twizzles around on one or two of the steps. He looks like he is searching for the way down but never finds it. Other monsters, such as knights and hell knights, are fine and follow the same path_corners without any trouble.

Is this a bounding box issue and do I need to allow more room on one side going in one direction?

For instance, I seem to remember that in the xy view, the lower left hand corner of the path_corner is significant. But could there be relevance to the direction of travel so that I should allow more room on one side in one direction but more room on the other side in the opposite direction?

There is only one monster on this path and no other monsters can cross the path, or otherwise get in the way of the ogre. 

Well, Hell Knights have the same bounding box as the Ogre so I'm not sure what could be going on... 

id1 Ogres as the same size as a Shambler, so if there's a bottleneck smaller than 64 units they can get stuck. 

If you use your own progs, you can simply give ogres the smaller bounding box. 

No they don't. Hell knights use the smaller box, ogres use the larger box.

If the ogre is going up fine, but not down, then you need to raise the ceiling by the height of the step. If it still doesn't work, then keep increasing the ceiling height. But 1 or 1.5 x height of step should be enough.

For gb's suggestion to work, you would need to make them use the smaller box. And yes, they do completely fit inside it. 

in order for a monster to take a step, it has to have it's 4 corners of it's bbox 'on ground'. the monster is allowed some leeway, but if the steps are too short, it would have to 'skip a step' which makes the vertical distance too far down.

essentially, the big monsters need bigger steps. :P 

obviously, without seeing the map, i can't be sure, but i don't think it's a ceiling issue.

the check when walking up a step is different from when walking down.

it is allowed to step up more than it is allowed to step down. 

Aaah yes, I think you might be onto something.

When stepping up, the front corner(s) need to be moving into something, and have a place to stand that is less than maxstepheight (there is a cvar for this, default is 18).

When stepping down, however, it's something like the middle of the box needs to be above a point that is no more than maxstepheight away, while the back corners are still on the top step.

This suggests that the only thing that will work, is either a smaller bounding box, or wider/shallower stairs. 

"in order for a monster to take a step, it has to have it's 4 corners of it's bbox 'on ground'. the monster is allowed some leeway, but if the steps are too short, it would have to 'skip a step' which makes the vertical distance too far down.

essentially, the big monsters need bigger steps. :P"

Are you sure? Ogres can navigate standard sized stairs in most maps that I've made. I've never had a situation where I needed to make stairs deeper to accommodate the bigger bounding box ... or maybe I've been doing it just automatically and not running into this. I dunno! 

So I guess that I'll stop trying to get the ogre to walk down the spiral(!) staircase then.

Mind you, he looks quite funny when he is twizzling on a couple of stairs (he sort of dances between them) and I may leave him there just to give the player a laugh before he blasts the ogre's head of with both barrels.

Thanks for your help everyone. 

That clears it up :) 

spiral, yeah. monsters have even more trouble navigating down stairs that are at an angle. even if all the steps are 45 degrees.

remember that bboxes don't rotate, so when the square bbox hits, say, a 45 degree angle, his leading corner will be even further out than usual (owing that it's a diagonal relative to the 45 degree step). you need to make your steps even bigger in that case.

note that if your steps are in an L shape, they can have trouble on the corners of the steps as well.

willem: now that we know that the map has spiral stairs, it's probably more owing to the non-right angled stairs, but you can see this for yourself by building a stair that is 16 units high and 16 units long. small bbox monsters should still be able to use it, but large bbox monsters will treat it like a ledge. 

http://img202.imageshack.us/img202/287/fitz0017.jpg
http://img94.imageshack.us/img94/3716/fitz0018.jpg

"He was twizzlin' away, 'till the closing of day, and singing a smoke-twizzlin' song. There was an aeroplane circlin' but he didn't notice at first, 'cause it was so cunningly disguised as a dragon." 

trigger_monsterjump (or whatever it's called)

SOLVED! 

Make a pillar so the steps closest to the internal bit of the U aren't so short - the outer width of the steps looks fine for even fatboy to walk down them.

Alternative2:
http://www.mobility-superstore.com/stairlifts/

Might be tricky setting up the func_trains though. 

That's just what I need, never mind the Ogres! 

A large bounding box? 

...oh yes, my box bounds large.

I got round the 'problem' with my ogre by setting the path_corners right next to the right hand side of the stairs where the tread is widest. He goes up and down with a slight twizzle on one step. The downside is that he does not appear to walk on the stairs, he looks as though he is floating above them.

But at least in gives that degree of randomness associated with wandering monsters.

Onwards and upwards, as they say... 

Anyway - I didn't think of the path_corners - you can already tell him where he supposed to be.

Looking forward to it, always liked shallots. 

How come the Ogre stops, when there's a 16 or 32 gap on its pathway?
I tried the OldOgre , but he always stops as soon here's a 16 unit gap.
I even tried a clipbrush of 8 units.
To make the screenshot I had to force the Ogre on the midle of the path.

http://members.home.nl/gimli/OldOgre.jpg 

monsters use the visible geometry (hull 0) to do pathfinding checks. So even if the collision hull (hull 1 or 2, depending on the monster) is flat and continuous, the monster will stop if there is a visual gap. (visual gaps that are 16 or less units deep are okay because they are treated as a step down.)

So, clip brushes won't help because they are not included in hull 0.

Func_wall with a skip texture might work, through. 

I wondered why I couldn't let him walk the hallway, while in the old screenshots it does. 

like a viking ogre or something :) 

hehe weardo :) but look sweet!

Ogres and Vores are my favorit monsters of Quake!!!

Awesome to dance with!