that the older .map formats don't support texture rotation in a way that works well, or at least not with accuracy. It takes a lot of fiddling around in a pre-v220 editor when you try to get alignment right in the more complicated parts. It's why QuArK was made from the start, to address texture alignment.

That's one of the reasons that I think explain why the original levels in Quake (and Quake II for that matter) were so blocky (and even then the textures weren't always... right). Try and do a simple five section 90 degree curved wall or arch in the original .map format and you will see what I mean. Sure you can get it to align simpler textures (or at least make it unnoticeable to the casual viewer) but it's not intuitive and what works one time may not work the next time.

I once abandoned an entire Egyptian themed map because a central area just wouldn't line up texture-wise no matter how much I tried to tweak it (hieroglyphics themed textures pointing to areas that you needed to go to next) and it just really messed up the entire feel of it. The WC 1.6 .map format just can't handle that fine level of detail. It wasn't written with that in mind. 

Best practice would be avoiding rotations or flips while using texture lock, and not modifying the world/face projection. (As these are the two spots that cause issues.)

It could be a nice feature to have for those who want to use the editor for a variety of older games though. (Like myself! Currently I use http://www.ogier-editor.com/mapconv/ to build levels in Hammer) 

I agree, however sometimes even that doesn't work out so well with the pre-220 .map format.

As long as you stick to the grid and keep it somewhat limited in angles, 99% of the time you won't have any issues at all. It's when you start adding things like arches, curved walls and so on that the older texture methods used pre-220 start to get misaligned. You can of course tweak them in most cases (or hide them by using flatter textures or textures where, by their organic nature, allows for mismatched faces) but I can't tell you how many times I've had to stretch, skew, rotate or otherwise tweak an angled surfaces texture to get it to match the one next to it and look right.

I suppose I was just too anal about that stuff to let what the player would probably never notice anyway to slide. 

For the reasons explained above.
The conversion from 220 to pre-220 formats is not straightforward and in certain cases lossy, resulting in texture alignment bugs. This will also ruin one of the most brilliant Hammer features named "seamless texturing" (Alt+click).
"Brush primitives" used in some Q3 editors are also quite limited.
But, it is extremely easy to add 220-format support to any pre-220 compiler! Jackhammer comes along with 220-capable Q1 and Q2 compilers. Their source modifications will certainly be available. 

Here's why:
Say you cut up the floor into tris and then select 3 of these wedge brushes that share a vertex in the middle. Enter vertex mode--time to make a hill. In Hammer or Worldcraft you have to drag a selection box around that point to select all 3 verts from all 3 brushes. (okay 6 verts unless they're tetrahedrons(recommended!)) NOT SO IN JACKHAMMER!! :D Just click the vertex that's shared and TADA! all are selected. This is a huge time saver when working with tri-soup (trisoup? tri soup?) or anything really that requires multiple brushes in vertex edit.

Eat your heart out Valve. Jackhammer is already better and more stable than your precious Hammer with it's downdates and downgrades and hacktches. (see what I did there, I hate it when an update breaks something)

Puhshaw! Who needs displacements (or a displacement to brushes converter)? 

Is it possible to save your map as a .MAP file in jackhammer? 

only in map 220 format.
No way to save a generic map, because specific texture axis handling in Jackhammer. 

Is Jackhammer still in active development? If so, could you share any new features or changes planned in the next version? 

I'd be interested in this too. 

Ditto. 

>>Is Jackhammer still in active development?
Yes. In the next version there will be Quake3 support. With patches, realtime shader script rendition, wysiwyg shader editor, and so on.
And some other additions, e.g. fully functional Path Tool. 

If you understand Russian, you can monitor some progress here:
http://hlfx.ru/forum/forumdisplay.php?s=&forumid=35
And even download pre-release Linux-only versions. 

I'm only interested in the Quake 1 aspect of Jackhammer, but that's good to hear Jackhammer is still being worked on. You guys are doing terrific work with it. 

So cool, always wanted an editor for Quake 2/Quake 3 engine games with hammer-like interface.
But please, add the Alt-E (vertex scale) tool from hammer, it's a VERY useful feature.
Waiting for Q3 support! 

Is there a way to hide all entities? When i push the button "hide entities" it doesn't hide all entities
The monsters/lights still remain

And one more time, how to navigate through the level via built in camera, is there a way to place more than only ONE camera?! 

>>add the Alt-E (vertex scale) tool from hammer
It is already there, in 1.1.320. :)
>>When i push the button "hide entities"
Where is this button?
>>is there a way to place more than only ONE camera?!
Nope, sorry. 

but jackhammer menu is the same
http://www.imagebam.com/image/14e1d2346550899

multicam from hammer
http://www.imagebam.com/image/6f0f3a346551136

Nope, sorry.
it is very handy and useful feature 

>>but jackhammer menu is the same
Items means items, weapons, etc. :)
Well, you can hide all entities using Entity Report tool, by selecting all the list and hit "mark", and then "Hide selection".
At least, in JH.
>>it is very handy and useful feature
Yeah, I know. But not essential as many other features. Maybe, some day... 

That would have saved me about 45 minutes of extra mapping time...

Autosave. 

Autosave is already present. Version 1.1.320. 

And my apologies, but is version 1.1.320 not released yet? On the website the only available version to download is 1.0.155.

Do you plan on releasing this new version soon? 

http://hlfx.ru/forum/showthread.php?s=&threadid=4449
The reason it is not published on the website is that this is a Linux build only. There are still some minor bugs. 

I do look forward to the Windows version when it is ready. You guys are doing excellent work :) 

Is there a way to have spacebar move you around the 3D view and also allow you to pan around in the 2D views as in Hammer? I don't know if that's been added since. Also have some issues with it not registering spacebar is held down when attempting to move in 3D window and it clicking/selecting brushes instead which is a pain! 

I didn't try this when it got released and I now regret that. After watching Daz map on twitch yesterday I decided to try it out.

This editor is good. REALLY good.

I have a few things I'd like to see changed or improved but what there is already is outstanding.