Below is a tutorial for how to use Reflap as written by user Fortine_oo from the now defunct website, nrtracks.com. I found that it was the best written tutorial and, since the site is now gone, it was time to bring it back to life for future racers.

A tool that can come in handy in the process is:

Replay to LP converter v1.2 – Nigel Pattinson
This small program will allow you to run laps in a testing session, save the replay, and then turn any of the saved laps within that replay into an LP file. It’s GREAT for creating an LP file, but it can cause a splicing issue, which is actually represented in the photo at the top of the screen. An LP file will start & end at the start/finish line when using this program. If you do not pass exactly across the stripe where you started, you’ll see a small disconnect in the race line, which will cause the AI to stutter/slow down as they try to correct to the line. This can be resolved by either splicing or smoothing. All of which should be covered decently by Fortine_oo below.

Reflap Hotkey Quick Reference Guide – Dr. Noise Paints
This is just a text file that includes all the hotkeys necessary for use within reflap. It is something I created for myself to print out and keep beside me when editing a track’s LP files.

Reflap is an integral part of NR2003, it’s not a separate program.

It will open in either Testing Session or Single Race mode and you will be able to turn on the various lp’s so they become visible (as colored triangles).

You can only create lp’s in Testing mode. View the lp’s in Race mode so you can see how the ai are affected by the lp’s.

***This is a tutorial on how to use the Reflap tool.***

***These are the directions for making a workable lp, it’s not an explanation on how to make lp’s that affect ai perfomance.***

Start Reflap:
You need to execute four keystrokes simultaneously, [ Ctrl + Alt + Shift + ~ ]. If the game recognized the keystroke(s) entry, red text (see below) will appear in the top left corner of the screen.

(Once you’ve selected a track, you may start Reflap at any time (and turn on the lp’s), however the “red text” will only be visible from a live in-car view.)

If a track already has lp files, they will become visible when you start reflap and then use the following keystrokes to turn on each individual lp:

Each lp made visible will stay visible until you hit the same keystrokes again.

• minrace.lp: [ctrl+1] – DarkGreen – Right of the race.lp
• maxrace.lp: [ctrl+2] – DarkGreen – Left of the race.lp
• pit0.lp: [ctrl+3] – Red – Normally between the minpit0.lp & maxpit0.lp
• minpit0.lp: [ctrl+4] – Dark Red – Normally right of the pit0.lp
• maxpit0.lp: [ctrl+5] – Dark Red – Normally left of the pit0.lp
• pit1.lp: [ctrl+6] – Blue – Normally between the minpit1.lp & maxpit1.lp
• minpit1.lp: [ctrl+7] – Dark Blue – Normally right of the pit1.lp
• maxpit1.lp: [ctrl+8] – Dark Blue – Normally left of the pit1.lp
• race.lp: [ctrl+0] – Green – Normally between the minrace.lp & maxrace.lp  
• {The race.lp will jump around (the ai are constanly evaluating the best racing-line path) when viewing from an ai’s camera view. It’s easier to view the race.lp by copying the race.lp and re-naming it to raceline.lp.}
• raceline.lp: [r] – This is not an lp for the ai, it is a visual reference for the Player, not a part of reflap.   
• minpanic/maxpanic.lp: [crtl+9] – Fuschia – Visible only as a pair. (Proper orientation (left/right) can only be determined by re-naming each to a single viewable lp.)
• limp.lp: – [Not able to select it via keystrokes, it can only be seen by re-naming it to a single viewable lp (and using that lp’s keystrokes).]

Creating an LP

1.) Start NR2003, select Testing Session.
2.) Go to track, select Drive.
3.) Start Reflap, [ Ctrl + Alt + Shift + ~ ].
4.) Start the recording process, “stashing”, with the combination keystroke(s) [ Alt + r ].

   {If you want to see the yellow (stashing) triangles being laid down, use the combination keystroke(s) [ Ctrl + ~ ]. I usually do this when I’m creating all the lp’s except the race.lp. Since a race.lp usually takes multiple laps to get one worth saving, having the yellow triangles visible becomes distracting when you begin another lap. I have  [ Ctrl + ~ ] mapped to a button on my wheel, so I only turn on the “stashing” triangles right before I’m ready to copy/save the lap because you need to be on the previous lap’s line when your ready to save. If you’re not “on the line” (or very close – reflap will smooth the transition point) the lp will stop at the save point and jump to the point of the previos lap. The ai will not be able to interpret their direction and slow dramatically before resuming to the continuing lp location.} 

As long as you’ve made at least one full lap, and you can drive on the yellow triangles of the previous lap, it doesn’t matter where on the course you actually save the lap. The saved lap will be interpreted as beginning at the S/F line and terminating at the S/F line.  

   [It helps car control if you get some heat in the tires, even if you’re going to be driving somewhat slowly.]

   [Smooth time is 3.0 seconds by default. I’ve never found it necessary to change this, although it is possible to increase or decrease the smoothing time. You can adjust smoothing time in increments of 0.5 seconds, from 0.5s to 5.0s, by pressing the [ ctrl + – ] [ and ctrl + = ] keys.]

5.) Save the lap (reflap directions call it “copy” the lap) with the keystroke [ / ], the yellow triangles will turn to orange. At this point you’re only saving the lap temporarily. You can continue driving so you can review the location of the lap on the course.

{The race.lp is the only lp that’s speed sensitive while recording. When it comes time to save a lap as a race.lp, maintain your throttle position while making the keystroke. The ai will mirror any throttle change, in fact they will more than likely magnify the change, usually slowing or losing momentum dramatically. A long, full throttle straight is easiest place to save a race.lp lap.}

[You can turn “stashing” off to stop recording a lap [ Alt + r ], then you “copy” the lap [ / ]. This is an unnecessary extra step.]

6.) Save the lap with the combination keystroke(s) [ Ctrl + / ]. It will appear in the track folder as reflap0.lp. Subsequent lp’s made during the same session will be saved as reflap1.lp, reflap2.lp, etc.

DO NOT FORGET to do this step or your work will be in vain.

7.) After exiting the session, rename reflap0.lp to the lp’s useable name (e.g. minrace.lp), and do likewise for any other lp’s created.

{Any reflapX.lp that is not renamed will be overwritten by any new reflapX.lp created in future sessions.}

The text in the upper left hand corner, when Reflap is turned on;

1) When you turn on Reflap:
    Reflap info stashing turned off smooth 3.0s, line -1:none 0:00.00s

2) When you turn on “stashing”: Reflap stashing turned on
    smooth 3.0s, line -1:none 0:00.00s

3) When you “copy” a lap: Copy from temp to work reflap
    
Reflap info stashed for (a number)_which is the current reflap index_not important smooth 3.0s, line -1:none 2:30.11s (the time spent creating the lap – useful information when creating a race.lp)

4) When you “save” a lap to the track folder: Saving working reflap ‘reflap0.lp’ (or ‘reflap1.lp’, ‘reflap2.lp’, etc)

Reflap info stashed for (a number)_which is the current reflap index_not important smooth 3.0s, line -1:none 2:30.11s (the time spent creating the lap – useful information when creating a race.lp)

A quick word about “splicing”, i.e. changing a portion of an existing lp.
It’s an option, but I find it just as easy to make a completely new lp, even on a long track. I suppose if you’re working on Nurburgring or Isle Of Mann, splicing may be the way to go…

Splicing a race.lp would be beneficial because it’s difficult to create a completely perfect at speed lap, but because the race.lp is speed sensitive, splicing it while maintaining the proper speed and direction is next to impossible.