DeeDoubleU, someone else is bound to have a far better answer than me, but the mean time I'll risk embarrassing myself:

AFAIK both of these behaviours are known bugs but nobody knows exactly why they happen. I recall having read a few discussions where experienced mappers were stumped, especially by the Scrag thing. According to this post you might be able to avoid the issue by not cramming too many of the offending monster into the same enclosed space...

Or wait for someone who knows what they're talking about to answer. :) 

It's a weird bug caused by the navigating I believe since both fish and the scrag use point collision (not bbox) to manage their movement, but a bbox to receive collisions.

So they find a bit of geometry that they don't like for some reason and it pops them into an invalid volume outside the world, and then they can't get back in.

Scrags usually can because the flymonster behaviour gives them a bit more movement.

I suspect its something to do with the discrepancy of the center point and the bbox corners.

I know that brush misalignments can cause this (like with the player), but so can perfectly clean brushwork that the offending monster manages to get stuck on and then clip through.

Mapside, the solutions are basically either delete your fish or change the areas where they are used until it stops happening.

Scrags are best used outdoors so that they don't push themselves up through a ceiling trying to match heights with the player - which seems to be the main cause of this for them.

This was the main reason I experimented with small fish, but ran out of time / gave up before I could get a decent handle on it. 

I've seen scrags move through solid geometry many times, but I don't remember ever seeing flying fish. Maybe that's just because fish aren't used nearly as much. 

I use trigger_multiple but I don�t know how to use the specifics. 

If you want a message to stay on the screen longer, you can string multiple triggers with delays containing the same message.

Add \n to start a new line if a message becomes too long.

Not sure what you are asking but that's a start for messages in vanilla Quake. 

Key 'message'
Data 'whatever you want to say' 

I need advice.

What's the appropriate combat for a maze-like map? I mean, in a set of interconnected hallways how encounters should be? 

Every ten seconds, two front spawns and three back spawns in bbox contact with the player. 

What Kinn said. 

 

I believe he said spawns... ;) 

 

OK, im working in it now 

So rare, I add a specific in a trigger in QuArK and it does not able, but I make again in TB and it does work. Im yet working... 

It's normal that QuArK finds holes in the map without being it? I brushing in TB but when I open QuArK to Qbsp and test, sometimes said "there is a hole in your map" and time later I do not move any brush, I change a trigger config and it back to Works in qbsp. 

Quark stores no floater points on brushes, so every time reloading the map it slightly differ integers. So mostly there is that message.

Better take a "better" editor, took time to use GtkRadiant or TB.
There is the option to select all verts and force them to grit. 

1. In such a way you think it'll be fun.

2. Play map.

3. Alt tab out if you think of a way it could be more fun.

4. Make change in editor.

5. Alt tab back to game.

6. Repeat step 3.

7. Once level is complete, recompile.

1. Repeat from 1.

This is the recipe for getting good. 

MadFox: GtkRaadiant have visible grid lines? 

 

i just fill every available space with monsters. 

 

what trigger I need for an Introduction changelevel???...... or what specific???... 

But actually you all ended up giving me an idea. Let's see if it works.

Also, what Qmaster said. 

GtkRadiant1.4 has several coloured grid settings, I prefer white lines on black.

Introduction changelevel?
Put in a trigger_multiple, add a corresponding trigger brush, and fill in a short message.
Or if you ment tigger_changelevel and fill in the map you want to continue with, e1m2. 

When you enter to a level from start.bsp, appears "loading".
But when you enter from a single map, appears "kills 13/13, secrets 2/3".

I don't know what to put in the Introduction(start) for going to e1m1.