I often see questions about glides (getting through a 32-unit wide gap), and there is random information all over the place which makes it difficult to get the basics for speedrunning purposes. I'd like to have some place to refer to when this question pops up, so here's a summary of the stuff I know about 32 unit glides. This is all non-TAS methods.
There are several different types of glides in doom:
Guideless glides in west, south, north and east direction.
Guided glides with the wall on your left in same directions as above.
Guided glides with the wall on your right in same directions as above.
as well as special type of glides like:
Torch glide on map 19 of Doom 2 (not 32 units)
glide between the bars in map 22 of doom 2
glide between the middle opening on map 21 of doom 2 (not 32 units)
Void glide on E2M6 of doom 1 (no gap)
All those glides should be possible with -longtics, which is the default turning resolution if you are not recording any demos. Since glides are primarily used for speedrunning the command -record is used, which enables -shorttics by default.
For -shorttics there are much fewer possible angles and which you can face (lower turning resolution). If you don't understand what I mean above then trying -record or -shorttics should make the difference obvious. This is an advantage when dealing with most types of glides, while possibly a disadvantage for some. I first learned how to glide without using -shorttics, which is very difficult to do, but possible.
So, before attempting to do glides, use -record or -shorttics command as launch parameter. Once you understand how the glides work you can try to do it without -shorttics if you intend to use it outside of demo recording.
Second thing you will need is vertical mouse movement, this is not always required, but even when it is not it may have an advantage. Also different sensitivities can have an effect, too high and you can't do a west directed glide, too low and you need to use more vertical mousemovement to move forward which makes it more likely that you end up turning left\right instead.
The two first things you need to do is to find the correct angle and the correct position for the glide to work.
The correct angle is when you are facing the gap and walking\running against the wall, but only moving slowly towards the left.
The correct position is when you are not moving any further to the left. For a guided glide with the wall to your left you will have the wall to stop you.
For a guideless glide there are 2 directions in which you will stop, west and south. So when you are close to the gap in the west direction you walk (not run) into the gap until you stop moving forward. In the case of a south directed glide you need to take a step back and walk forward again. If you don't do that then there is a chance you will just continue further to the left and go past the gap.
Once you have stopped moving forward you need to use vertical mouse movement. The reason for this is because you will be able to do much slower forward movement than normal (like walk with W or up arrow) that is necessary (in some rare cases you go straight through before you stop) for the glide to work. For west directed glides the slowest possible speed (MF1) should be necessary, for south directed glides you need a slightly higher speed (MF2). The lowest possible speed for strafe on + mouse turn is SL2\SR2 which means vertical mouse movement is not necessary for south direction. I am not sure what speed is needed for east and north directed glides, but using the smallest possible speed and then increasing it should be the best method (I think it's MF2).
All the glides listed above are possible, there are different methods that if performed correctly will get you through the gap. So there is no randomness involved, but how fast you are able to get through depends on how quickly you can get the right angle, correct position and apply the correct amount of vertical mouse movement.
We here look at the correct angle, position and vertical mouse movement speed for most types of glides using -shorttics.
Direction: for example west directed means going east to west (right to left) direction as from looking on the minimap while facing the 32-unit gap, and wall to your left\right is when you are facing the 32-unit gap.
Guided glides with the wall to the left:
These are easy to do with the method described above. Some examples are Map 16 (east) and 21 (west) of doom 2 and map 21 (west) and 23 (north) of plutonia. Since map 16 is east directed it is slightly more difficult to do than map 21 which is west, but with practice they should take almost no time besides finding the correct angle.
The easiest type of glide is a guided west directed glide with the wall on your left while facing the gap. This type can be found on map 21 of doom 2. I would recommend if you haven't done a glide before to do map 21 of doom 2, which is through the closest teleporter and 45 degrees turn to the left.
Alternative method for East and North directions:
I recently discovered another way to do these glides during 30nm attempts. You need to be facing 45 or so degrees to the right compared to the usual angle if you are doing an east directed glide, then you SR50 along the wall (wallrun) into the gap. You should then be wobbling back and forth a lot, by using vertical mouse movement very slowly backwards (MB1) you will then go straight through after a short while (you will wobble less just when you are about to get it, if you don't wobble at all you used MB2 or higher, see 30nm2721 for example).
Guided glides with the wall to the right:
These types of glides are useless for all the IWADs, since there exists guided with the wall to the left instead for all of them afaik.
Either way, west and South directed glides are also somewhat easy to do with the above method. For an east directed glide you need to use a different technique, lv14-014 (map 14 of doom 2 uv-speed) shows this trick (no glide, different trick). You have to aim 1 tic to the left of being parallel with the wall and use continuous vertical mouse movement while you turn 1 tic to the right. This will get you close to the wall (by strafing against the wall you will notice that your gun wobbles a lot if you did it correctly) which will allow you do go through east directed guided glides with the wall to the right. North directed glides with the wall to your right are not possible afaik, unless you use melee attack (see below). You can find this glide on map 16 of doom 2, but it's useless since there's an east directed guided glide with the wall to your left. (I never do these types of glides and so I might be wrong here, I just quickly checked it at some point)
Guideless glides (all 4 of these types can be found in the same place on map 19 of plutonia):
From running plutonia I have discovered consistent method for how to do south directed and north directed glides. It also turns out east directed glides can be done consistent as well, but are really precise and therefore hard to do.
West directed glide is the easiest of these, and the method for it is described above, just apply the 3 steps: Position, angle and vert. mouse movement. Map 2 of doom 2 and map 8 of plutonia has this type of glide.
South directed glide can be difficult to do, also described above. Map 9,13 of plutonia has this type of glide.
North directed glides might be very difficult to learn. Once you notice a very thin line kind of move out of place on the left side you apply a very small amount of vertical mouse movement and the glide should work every time. However, it can be very difficult to not move past the gap when you try to get in the right spot. I think MF2 tics are needed to get through, but MF1 tics doesn't move you out of the gap, so by using a small amount of vertical mouse movement you eventually go from doing MF1 to MF2 which then gets you through.
You need to apply some vertical mouse movement before you start moving forward into the correct position. If you don't do that then you will move slightly to the right when you try to do the final step, but then you can just move forward to the line moves again so it's not a big deal. So you very carefully tap move forward until you see the change, and then you start to use vertical mouse movement. If done correctly, it works 100% of the time, after some practice this type of glide is not much more difficult than a south directed glide. Map 13 of plutonia and E4M4 has this type of glide.
East directed glide, same as above, except here you move forward until you see a line segment move out of place on the right side. Once that happens you need to take a step back and move forward and use vertical mouse movement.
East directed glides are difficult to describe any further, but since it's useless for IWADs I won't even bother, the setup for it is slow so for short IL's where it could be useful it would be best to just randomly try to get the right position and use vertical mouse movement. Perdgate 7 and 15 has this type of glide.
Special type of glides:
Map 22 of Doom 2 (bars glide): There is 1 specific angle that will get you through easily, make sure to take a step back and use run forward + strafe left. I also have an alternative method here, but it's hard to describe so I won't. See 30uv1959 for example, credits to Looper for the method.
Map 19 of Doom 2 (torch glide): Face the gap, take a step back and run forward + strafe left, there are several angles which will get you through.
Map 21 of Doom 2 (SR50 glide): Using a specific angle you can SR50 through the gap, not very useful. Some IL probably uses this trick.
Doom 1 E2M6 (Void glide): There are several angles which this glide works, some are better than others. Then running back and forwards will get you through eventually.
Alternative to vertical mouse movement:
Another possibility is to take a step back and go forward, repeat until you get through. This should work for west and south directed glides, though I am not 100% sure because I don't use it as this method is completely random and thus slower. Speed does not matter (as far as I noticed) so to get through as quick as possible you just have to minimize the time between each bump.
And that's as much as I can be bothered to describe glides, some questions like what is the correct angle to use for void glide could be answered by watching demos. If anything is incorrect feel free to correct me or if you have anything to add then please do.
One last thing, using melee(fist,chainsaw) on a monster will make a change so that when you move against the wall at any angle you will not be moving slowly towards the left. You can also return to the initial "angle" by furter attacking with melee, or you can even move slowly towards the right so that east\north glides are easy instead of west\south, either way just try to punch\chainsaw monsters and attempt to glide to see what I mean.
Last edited by ZeroMaster010 on Aug 28 2015 at 14:57